[gentoo-user] Advice/best practices for a new Gentoo installation

[gentoo-user] Advice/best practices for a new Gentoo installation

[Paul Hartman]

Hi, I'm building a new personal computer. I respect the opinion and
experience of the people on this list and am interested in anyone's
advice on the best way to set up my new Gentoo installation. Things
that you say "I wish I set mine up this way the first time..." or have
learned from experience how to do it right the first time already. :)

Some topics I'm thinking about (comments welcome):
- be aware of cylinder boundaries when partitioning (thanks to the
recent thread)
- utilizing device labels and/or volume labels instead of hoping
/dev/sda stays /dev/sda always
- initrd - I've never used one, but maybe it's needed if root is on
software RAID?
- grub/kernel parameter tips and tricks... i'm already using uvesafb,
and don't dual-boot with MSWin or anything, just Gentoo
- better partitioning scheme than my current root, boot, home (need
portage on its own, maybe /var as well?)
- some kind of small linux emergency/recovery partition? equivalent to
a liveCD maybe.
- best filesystem for portage? something compressed or with small
cluster size maybe.
- SSD vs 10000rpm vs big-and-cheap hard drive for rootfs/system files.
I lean toward the latter since RAM caches it anyway.
- omit/reduce number of reserved-for-root blocks on partitions where
it's not necessary.
- I have never used LVM and don't really know about it. Should I use
it? will it make life easier someday? or more difficult?
- Is RAID5 still a good balance for disk cost vs usable space vs data
safety? I can't/don't want to pay for full mirroring of all disks.

Or any other tips that apply to things which are difficult to change
once the system is in use.

It will be ~amd64 Gentoo using Intel Core i7 920 with 12GiB RAM. No
disks have been purchased yet.

Thanks

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Kyle Bader]

> - be aware of cylinder boundaries when partitioning (thanks to the
> recent thread)

+1

> - utilizing device labels and/or volume labels instead of hoping
> /dev/sda stays /dev/sda always

+1

> - initrd - I've never used one, but maybe it's needed if root is on
> software RAID?

It's not technically needed and boot times are faster without them.
I'm a fan of statically compiled kernels too but that's more to
prevent malicious LKMs.

> - grub/kernel parameter tips and tricks... i'm already using uvesafb,
> and don't dual-boot with MSWin or anything, just Gentoo
> - better partitioning scheme than my current root, boot, home (need
> portage on its own, maybe /var as well?)

putting portage on it's on partition is a good idea imo, I usually use
reiserfs because it handles large amounts of small files well.

> - some kind of small linux emergency/recovery partition? equivalent to
> a liveCD maybe.

I usually keep a bootable usb in my bag for recovery, which also works
if there is a problem with the disk/raid.

> - best filesystem for portage? something compressed or with small
> cluster size maybe.

reiserfs

> - SSD vs 10000rpm vs big-and-cheap hard drive for rootfs/system files.
> I lean toward the latter since RAM caches it anyway.

SSDs can make things snappier for boot times.  Having lots of ram for
disk cache eliminates the benefit after booted since ram is even
faster than a SSD.

> - omit/reduce number of reserved-for-root blocks on partitions where
> it's not necessary.

I never get close to filling my disks so never have bothered with this

> - I have never used LVM and don't really know about it. Should I use
> it? will it make life easier someday? or more difficult?

I'm not a fan, if you don't plan on changing your partition sizes I
don't see a lot of utility in adding the extra layer of complexity.

> - Is RAID5 still a good balance for disk cost vs usable space vs data
> safety? I can't/don't want to pay for full mirroring of all disks.

It's better than no raid but as you probably know it will only allow
for a single disk failure.  Getting drives from different lots (but
same geometry) is recommended.
-- 

Kyle

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Paul Hartman]

On Fri, Feb 26, 2010 at 12:24 PM, Kyle Bader <kyle.bader@gmail.com> wrote:
>> - SSD vs 10000rpm vs big-and-cheap hard drive for rootfs/system files.
>> I lean toward the latter since RAM caches it anyway.
>
> SSDs can make things snappier for boot times.  Having lots of ram for
> disk cache eliminates the benefit after booted since ram is even
> faster than a SSD.

I decided on a hard drive for the primary disk rather than SSD. For a
combination of size (1TB), performance (according to benchmarks) and
price (according to my pockets) I chose a Samsung HD103SJ (7200rpm,
1TB, 32MB cache, 2x500gb platters) drive which appears to have great
overall performance and low operating temperatures.

I haven't received the disks yet so for now I'm just playing with an
old spare drive and installed Windows 7 (trial) for
configuring/testing the overclock settings since all of the
motherboard tools are in Windows only. Once I have it running fast &
cool, it's Gentoo time!

I also tried the Gentoo LiveDVD 10.1, written to a USB flash drive
(with unetbootin), and it worked great. I had the PC hooked up to my
TV with HDMI and it used proper 16:9 resolution, got DHCP address
automatically and everything seemed to simply work properly. It will
be great to use Konsole and Firefox during install, compared to having
a 80x25 terminal like I did many years ago in my last install. Good
job to the LiveDVD team!

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Willie Wong]

On Fri, Feb 26, 2010 at 11:54:13AM -0600, Paul Hartman wrote:
> - better partitioning scheme than my current root, boot, home (need
> portage on its own, maybe /var as well?)

/var if you are worried about log files piling up. I don't put portage
on its own, but I use reiserfs for / 

> - some kind of small linux emergency/recovery partition? equivalent to
> a liveCD maybe.

Isn't that what busybox is for?

> - best filesystem for portage? something compressed or with small
> cluster size maybe.

Reiserfs. That's more because of the tail-packing then anything else. 

> - omit/reduce number of reserved-for-root blocks on partitions where
> it's not necessary.

Yep. On a 200G drive, 10% is 20G: that's 4 movies!

> Or any other tips that apply to things which are difficult to change
> once the system is in use.

Pay attention to your make.conf? Make sure you get CHOST right. 
If you are dealing with unfamiliar options in the kernel, always start
at the bare minimum and make sure you keep a working copy around. 

W
-- 
Willie W. Wong                                     wwong@math.princeton.edu
Data aequatione quotcunque fluentes quantitae involvente fluxiones invenire 
         et vice versa   ~~~  I. Newton

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[BRM]

----- Original Message ----

> From: Paul Hartman <paul.hartman+gentoo@gmail.com>
> To: gentoo-user@lists.gentoo.org
> Some topics I'm thinking about (comments welcome):
> - be aware of cylinder boundaries when partitioning (thanks to the
> recent thread)
> - utilizing device labels and/or volume labels instead of hoping
> /dev/sda stays /dev/sda always

I've never had an issue with /dev/sda changing, but I don't change out hard drives a lot either.
If you're doing hot-pluggable systems may be. But it typically does the right thing.

I haven't gotten around to do doing it yet, but one thing I did think about was setting up udev to recognize certain external hard drives for use - e.g. always mapping a backup hard drive to a certain location for backups instead of the normal prompting.

> - initrd - I've never used one, but maybe it's needed if root is on
> software RAID?

You only need initrd if you can't build a kernel with everything needed to boot up - namely, when you need to load specialized firmware to access the hard drive or if you are doing net-booting.

> - grub/kernel parameter tips and tricks... i'm already using uvesafb,
> and don't dual-boot with MSWin or anything, just Gentoo

I typically make sure to alias or map a "default" that should always work. It's my standard boot up unless I"m testing out a new kernel build.
When I do an update, I add the update to the list without modifying the default until I've verified that the updated kernel is working.
Works better under LILO than grub if I recall.

> - better partitioning scheme than my current root, boot, home (need
> portage on its own, maybe /var as well?)

I have taken to putting portage on its own partition to keep from filling up the root partition, which I've done on a few systems more than once.
So yes, definately +5.

> - best filesystem for portage? something compressed or with small
> cluster size maybe.

1. Stay away from reiserfs. Yeah, I know there's a big fan base for it; but it's not so big in the recovery distro area.
2. Ext2/3 are now more than sufficient and supported out-of-the-box by nearly all recovery distros. I haven't tried Ext4 yet, but it seems very able as well.

From various things I've seen, XFS or JFS is about the only real FS to offer benefits where it kind of makes sense.
But for the most part, Ext2/3/4 will probably more than suffice for most everyone's need; and when it doesn't - you're typically doing something where you need to find the right one out of numerous for a specialized area of use, in which case, general recommendations don't cut it.

(Why care about recovery disks: B/c you never know when you're going to need to access that partition.)

> - SSD vs 10000rpm vs big-and-cheap hard drive for rootfs/system files.
> I lean toward the latter since RAM caches it anyway.

I lean towards just going the standard 10k hard drives with lots of cache; though I typically only buy the middle-line Western Digitals (upper-line being the server hard drives).

> - omit/reduce number of reserved-for-root blocks on partitions where
> it's not necessary.
> - I have never used LVM and don't really know about it. Should I use
> it? will it make life easier someday? or more difficult?

I tried out LVM (LVM2) thinking it would kind of make sense. I still have one system using it; but I ended up abandoning it.
Why? Recovery is a pita when something goes wrong. Not to say it isn't flexible, but for most people LVM is unnecessary, kind of like RAID.

> - Is RAID5 still a good balance for disk cost vs usable space vs data
> safety? I can't/don't want to pay for full mirroring of all disks.

RAID is not really necessary for most people. Save it for sections on doing backups - e.g. setting up a drive to backup to that gets mirrored off - or server support, where RAID is necessary.
But most users don't need RAID.
 
> Or any other tips that apply to things which are difficult to change
> once the system is in use.

KISS.
 
Ben

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[roundyz]

Paul Hartman wrote:

>> - some kind of small linux emergency/recovery partition? equivalent to
>> a liveCD maybe.
Tiny core linux on the boot folder/part. Its all in a single small file.


>> Or any other tips that apply to things which are difficult to change
>> once the system is in use.

I moved distfiles onto my home partition (bacause its huge), my root fs
is 5GB ext3, it never really changes much.

-- 
Regards,
Roundyz

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Frank Steinmetzger]

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Am Freitag 26 Februar 2010 schrieb Paul Hartman:

> Hi, I'm building a new personal computer. I respect the opinion and
> experience of the people on this list and am interested in anyone's
> advice on the best way to set up my new Gentoo installation. Things
> that you say "I wish I set mine up this way the first time..." or have
> learned from experience how to do it right the first time already. :)
> 
> Some topics I'm thinking about (comments welcome):
> - be aware of cylinder boundaries when partitioning (thanks to the
> recent thread)

Indeed. ;-)
I just applied that knowledge again yesterday on a friend’s new laptop.

> - better partitioning scheme than my current root, boot, home (need
> portage on its own, maybe /var as well?)

I use the root/boot/home scheme as well (500GB laptop drive). Though I used 
ReiserFS in an image file on / file system for a while, but dropped it later. 
Using an image file saves from fiddling with partitions and FS resizing in the 
process.

> - some kind of small linux emergency/recovery partition? equivalent to
> a liveCD maybe.

I always wanted to make my own Gentoo-based livecd that fits onto my old 128M 
stick. :o)

> - SSD vs 10000rpm vs big-and-cheap hard drive for rootfs/system files.
> I lean toward the latter since RAM caches it anyway.

I’m still caucios about SSDs because of their limited lifetime. I would only 
use it for /home or my media archive. But for the latter, it would become 
over-expensive fast, for they are more pricey by the GB than all other things. 
If it shall be a quiet system, I’d look into 2,5" drives, they also use less 
power than 3,5", on the other hand they are of course more expensive. :)

> - omit/reduce number of reserved-for-root blocks on partitions where
> it's not necessary.

I’ve set it to 0 on my home partition. I also reduced the inode count on my 
media, home and X-Plane partition. None of those have more than 60000 in use 
at the moment, whereas mkfs had given them about 3 to 4 million by default. 
I’m not sure though if that gives me any more available space.
-- 
Gruß | Greetings | Qapla'
This sentence no verb.

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Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Alex Schuster]

Paul Hartman writes:

> - utilizing device labels and/or volume labels instead of hoping
> /dev/sda stays /dev/sda always

Good idea. Or use LVM.

> - better partitioning scheme than my current root, boot, home (need
> portage on its own, maybe /var as well?)

I like to have many partitions. When my /usr/portage/distfiles or /tmp 
gets full, I do not want this to affect my system.

> - some kind of small linux emergency/recovery partition? equivalent to
> a liveCD maybe.

Maybe, but a liveCD is also fine and can be used elsewhere, too.

> - best filesystem for portage? something compressed or with small
> cluster size maybe.

I think reiserfs with the notail option is recommended.

> - omit/reduce number of reserved-for-root blocks on partitions where
> it's not necessary.

I reduce it for large partitions, but do not set it to 0 in order to 
prevent fragmentation.

> - I have never used LVM and don't really know about it. Should I use
> it? will it make life easier someday? or more difficult?

A little more difficult in the first place, until you get used to it. But 
if you need to change things later, it makes this much easier. /var is too 
small? Well, enter lvresize -L +1G /dev/myvg/var && resize2fs 
/dev/myvg/var and you have 1G more of space after half a minute. No need 
to take the system down, boot a rescue system and use parted.

Short how-to:
- create some partitions you will use for LVM (/dev/sda[56789])
- make them physical volumes: pvcreate /dev/sda[56789]
- make them a volume group:   vgcreate myvg /dev/sda[56789]
- create logical volumes:     lvcreate -L 5G -n usr myvg (/usr partition)
- create file system:         mke2fs -j -L usr /dev/myvg/usr

> - Is RAID5 still a good balance for disk cost vs usable space vs data
> safety? I can't/don't want to pay for full mirroring of all disks.

Probably, if you need RAID. But I'd say RAID is not a real backup, so you 
would need even more disks space for that. I prefer to use a 2nd disk for 
backups I make frequently with rdiff-backup. They have the same structure 
as the original, only that each partition has an additional 'rdiff-backup-
data' directory that stores the data of older snapshots.
Some months ago my main drive started having errors, so I took it out, 
booted with a CD, renamed the volume group of the backup disk to that of 
the original one ("vgrename backup system"), and that was all. Using RAID 
would have been even easier, but does not help when I accidentally remove 
a file, or want a file as it was a whiel ago.
Keeping the older snapshots needs some extra space, but this is 
compensated by not having to backup everything including 
/usr/portage/distfiles, /var/tmp/portage etc.

	Wonko

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Neil Bothwick]

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On Tue, 2 Mar 2010 10:35:42 +0100, Alex Schuster wrote:

> > - best filesystem for portage? something compressed or with small
> > cluster size maybe.  
> 
> I think reiserfs with the notail option is recommended.

The data I've seen indicates that ext2 is fastest, that's what I use.
There's no need for journalling on the portage tree, it's small enough to
fsck quickly and if it does get broken, reformat and resync.


-- 
Neil Bothwick

New Intel opcode #007 PUKE: Put unmeaningful keywords everywhere

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Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Mick]

On 2 March 2010 10:10, Neil Bothwick <neil@digimed.co.uk> wrote:
> On Tue, 2 Mar 2010 10:35:42 +0100, Alex Schuster wrote:
>
>> > - best filesystem for portage? something compressed or with small
>> > cluster size maybe.
>>
>> I think reiserfs with the notail option is recommended.
>
> The data I've seen indicates that ext2 is fastest, that's what I use.
> There's no need for journalling on the portage tree, it's small enough to
> fsck quickly and if it does get broken, reformat and resync.

Over the years I've had /usr/portage on reiserfs (with tails and all)
and xfs on laptops.  New machine has reiser4.  Seems blindingly fast,
but that's no comparison because the machine is more modern.
-- 
Regards,
Mick

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Alex Schuster]

Neil Bothwick writes:

> On Tue, 2 Mar 2010 10:35:42 +0100, Alex Schuster wrote:
> > > - best filesystem for portage? something compressed or with small
> > > cluster size maybe.
> > 
> > I think reiserfs with the notail option is recommended.
> 
> The data I've seen indicates that ext2 is fastest, that's what I use.

I thought the small files of the portage tree especially profit from the 
notail option in reiserfs? Did you change the block size?

> There's no need for journalling on the portage tree, it's small enough
> to fsck quickly and if it does get broken, reformat and resync.

Would the journaling overhead be noticeable? 
I also had used ext2 for my portage tree first, then I read somewhere that 
reiserfs would be the best. BTW, I have distfiles and pkgdir somewhere 
else, if not the fsck would not be so fast.

Just for fun, I just copied my $PORTDIR into my tmpfs, emerge -DpN @system 
@world takes between 81 and 53 seconds. With reiserfs, I get 130 seconds 
first ($PORTDIR was unmounted first and mounted again to clear the 
caches), and 57 seconds in the second attempt.

I had expected that tmpfs would be even faster. I think I just keep it the 
way it is now.

	Wonko

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Willie Wong]

On Wed, Mar 03, 2010 at 12:52:55PM +0100, Alex Schuster wrote:
> Neil Bothwick writes:
> 
> > On Tue, 2 Mar 2010 10:35:42 +0100, Alex Schuster wrote:
> > > > - best filesystem for portage? something compressed or with small
> > > > cluster size maybe.
> > > 
> > > I think reiserfs with the notail option is recommended.
> > 
> > The data I've seen indicates that ext2 is fastest, that's what I use.
> 
> I thought the small files of the portage tree especially profit from the 
> notail option in reiserfs? Did you change the block size?

You mean the other way around, right? reiser defaults to tail-packing,
which can cause problems with GRUB and LILO, which is why notail is an
option which turns off tail-packing for those crazy enough to use
reiser on /boot. 

If you use notail on the portage tree, you get rid of that advantage,
then Neil is absolutely correct: there's not too much point in
journaling the portage tree, and if you actively make reiser
not-competitive on the storage-space direction, the only metric left
to compare is speed, and ext2 is faster. 

Incidentally, if you are willing to sacrifice speed for space, then a
sparsefile for /usr/portage may also be an option. 

W
-- 
Willie W. Wong                                     wwong@math.princeton.edu
Data aequatione quotcunque fluentes quantitae involvente fluxiones invenire 
         et vice versa   ~~~  I. Newton

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Alex Schuster]

Willie Wong writes:

> On Wed, Mar 03, 2010 at 12:52:55PM +0100, Alex Schuster wrote:

> > I thought the small files of the portage tree especially profit from
> > the notail option in reiserfs? Did you change the block size?
> 
> You mean the other way around, right?

Oh dear. Yes. Thanks.

> reiser defaults to tail-packing,
> which can cause problems with GRUB and LILO, which is why notail is an
> option which turns off tail-packing for those crazy enough to use
> reiser on /boot.
> 
> If you use notail on the portage tree, you get rid of that advantage,
> then Neil is absolutely correct: there's not too much point in
> journaling the portage tree, and if you actively make reiser
> not-competitive on the storage-space direction, the only metric left
> to compare is speed, and ext2 is faster.
> 
> Incidentally, if you are willing to sacrifice speed for space, then a
> sparsefile for /usr/portage may also be an option.

I had this once on a smaller machine, but now I'd prefer it the other way 
around, there's plenty of space available. I have 15G for distfiles and 
pkgdir, so I don't worry about some 100MB for the portage tree.

	Wonko

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Walter Dnes]

On Wed, Mar 03, 2010 at 05:34:34PM +0100, Alex Schuster wrote

> I had this once on a smaller machine, but now I'd prefer it the other way 
> around, there's plenty of space available. I have 15G for distfiles and 
> pkgdir, so I don't worry about some 100MB for the portage tree.


  I managed to pull off a cute stunt that...
a) minimizes wasted disk space
b) retains the ability to wipe and re-install the OS, without wiping
   user data

  The example below uses /dev/sda and a 500 megabyte / partition.  I
think I could get away with 300.  Substitute as appropriate for your
system (hda or wharever)

Step 1) Partition a blank hard drive.

- partition the entire hard drive (500 gigabytes in my case) as one
  gigantic extended partition (partition 1)

- create a 500 megabyte logical linux (type 83) partition of at the
  beginning of the extended partition (partition 5).  This will be the
  / partition

- next, create a logical linux swap (type 82) partition approx twice
  the size of your ram (partition 6).

- next, create a logical linux (type 83) partition using the remainder
  of the drive (partition 7).  This will be mounted as /home.  Here's
  what my drive looks like, according to "fdisk -l"

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1       60801   488384001    5  Extended
/dev/sda5               1          62      497952   83  Linux
/dev/sda6              63         549     3911796   82  Linux swap / Solaris
/dev/sda7             550       60801   483974158+  83  Linux

  Step 2) File system creation... *WARNING* the following script wipes
all data on partitions 5, 6, and 7.  Use this only when you want to wipe
everything, *INCLUDING ALL YOUR DATA*, and start fresh.  For mounting
the drive after a reboot during install (or booting off the install CD
for rescue work) use the script in step 3.

#!/bin/bash
mke2fs /dev/sda5
mkswap /dev/sda6
mkreiserfs /dev/sda7
swapon /dev/sda6
mount /dev/sda5 /mnt/gentoo -o noatime
mkdir /mnt/gentoo/home
mount /dev/sda7 /mnt/gentoo/home -o noatime,notail
mkdir /mnt/gentoo/opt
chmod 1777 /mnt/gentoo/opt
mkdir /mnt/gentoo/tmp
chmod 1777 /mnt/gentoo/tmp
mkdir /mnt/gentoo/usr
chmod 755 /mnt/gentoo/usr
mkdir /mnt/gentoo/var
chmod 755 /mnt/gentoo/var
mkdir /mnt/gentoo/home/bindmounts
mkdir /mnt/gentoo/home/bindmounts/opt
chmod 755 /mnt/gentoo/home/bindmounts/opt
mkdir /mnt/gentoo/home/bindmounts/tmp
chmod 1777 /mnt/gentoo/home/bindmounts/tmp
mkdir /mnt/gentoo/home/bindmounts/usr
chmod 755 /mnt/gentoo/home/bindmounts/usr
mkdir /mnt/gentoo/home/bindmounts/var
chmod 755 /mnt/gentoo/home/bindmounts/var
mount --bind /mnt/gentoo/home/bindmounts/opt /mnt/gentoo/opt
mount --bind /mnt/gentoo/home/bindmounts/tmp /mnt/gentoo/tmp
mount --bind /mnt/gentoo/home/bindmounts/usr /mnt/gentoo/usr
mount --bind /mnt/gentoo/home/bindmounts/var /mnt/gentoo/var

  Again, substitute as appropriate if your harddrive is not /dev/sda.
Let's examine the script in detail...

mke2fs /dev/sda5
mkswap /dev/sda6
mkreiserfs /dev/sda7
swapon /dev/sda6

  The first 4 commands format the partitions and activate the swapdrive.
Partition 5 really should be ext2fs for a few reasons...

  - Partition 5 will rarely be written to during normal operation; only
    when you are installing/updating programs/scripts that reside in
    /bin or /sbin so journalling isn't that important.

  - Journalling requires disk space, which we're trying to conserve.

  - Given the small size of the / partition, ext2fs is sufficient

  - ext2fs is the easiest filesystem to shrink/grow.  If you ever need
    to grow the / partition in future, you can take space from the swap
    partition.  Unless you're doing a suspend-to-swap, you can screw
    around with the swap partition with impunity.

  - partition 7 will require a (preferably journalling) filesystem that
    can handle a large partition.  I currently use reiserfs.  There are
    several competent filesystems.  The choice is yours.

mount /dev/sda5 /mnt/gentoo -o noatime
mkdir /mnt/gentoo/home
mount /dev/sda7 /mnt/gentoo/home -o noatime,notail

  The next 3 statements

  - mount partition 5 as /

  - create directory /home on partition 5

  - mount partition 7 as /home.  All physical partitions are now mounted.

mkdir /mnt/gentoo/opt
chmod 1777 /mnt/gentoo/opt
mkdir /mnt/gentoo/tmp
chmod 1777 /mnt/gentoo/tmp
mkdir /mnt/gentoo/usr
chmod 755 /mnt/gentoo/usr
mkdir /mnt/gentoo/var
chmod 755 /mnt/gentoo/var

  The next 6 statements create /opt, /tmp, /usr, and /var, and set permissions.

mkdir /mnt/gentoo/home/bindmounts
mkdir /mnt/gentoo/home/bindmounts/opt
chmod 755 /mnt/gentoo/home/bindmounts/opt
mkdir /mnt/gentoo/home/bindmounts/tmp
chmod 1777 /mnt/gentoo/home/bindmounts/tmp
mkdir /mnt/gentoo/home/bindmounts/usr
chmod 755 /mnt/gentoo/home/bindmounts/usr
mkdir /mnt/gentoo/home/bindmounts/var
chmod 755 /mnt/gentoo/home/bindmounts/var

  The next 9 statements create /home/bindmounts/ on partition 7, and
then create mirrors of /opt, /tmp, /usr, and /var in /home/bindmounts,
and set permissions.

mount --bind /mnt/gentoo/home/bindmounts/opt /mnt/gentoo/opt
mount --bind /mnt/gentoo/home/bindmounts/tmp /mnt/gentoo/tmp
mount --bind /mnt/gentoo/home/bindmounts/usr /mnt/gentoo/usr
mount --bind /mnt/gentoo/home/bindmounts/var /mnt/gentoo/var

  And now, the connection between the directories in /home/bindmounts and
their equivalents on /, which makes the whole thing work.  If you ever
need to re-install Gentoo, or another linux distro, you can wipe the
contents of (*DO NOT* rmdir)...
/opt
/tmp
/usr
/var

  And then wipe everything in / except the 4 directories...
/home
/opt
/tmp
/usr
/var

  Step 3)

  OK, so you've set up the partitions and subdirectories.  There are
re-boots during the linux install process.  Ditto for installing a new
distro, or for doing rescue work.  Use the following script to mount the
directories...

#!/bin/bash
swapon /dev/sda6
mount /dev/sda5 /mnt/gentoo -o noatime
mount /dev/sda7 /mnt/gentoo/home -o noatime,notail
mount --bind /mnt/gentoo/home/bindmounts/opt /mnt/gentoo/opt
mount --bind /mnt/gentoo/home/bindmounts/tmp /mnt/gentoo/tmp
mount --bind /mnt/gentoo/home/bindmounts/usr /mnt/gentoo/usr
mount --bind /mnt/gentoo/home/bindmounts/var /mnt/gentoo/var



  The advantages of my setup...
  - a minimum of wasted disk space
  - you can create lots of files, and use almost the entire hard drive
    flexibly, because all the really variable stuff goes on the big
    partition
  - with a little care, you can wipe the OS files and keep your data,
    and re-install the same or another linux distro.

  Disadvantages...
  - "find" will show duplicate results if the target file physically
    exists in /home/bindmounts
  - in Gentoo, /etc/localtime is a physical file, not a symlink into
    /usr/share/zoneinfo.  If it is a symlink in your distro, scripts
    that execute early in the boot process might get confused about what
    time it is.


My /etc/fstab looks like so.

# <fs>			<mountpoint>	<type>		<opts>		<dump/pass>

/dev/hda1		/		ext3		noatime		0 1
/dev/hda5		none		swap		sw		0 0
/dev/hda6		/home		ext3		noatime		0 0
/home/bindmounts/opt	/opt		auto		bind,noatime	0 0
/home/bindmounts/var	/var		auto		bind,noatime	0 0
/home/bindmounts/usr	/usr		auto		bind,noatime	0 0
/home/bindmounts/tmp	/tmp		auto		bind,noatime	0 0
/dev/hdd		/mnt/cdrom	iso9660		noauto,ro	0 0
/dev/hdc		/mnt/dvd	auto		noauto,ro	0 0
/dev/fd0		/mnt/floppy	auto		noauto		0 0
/dev/SDReader    /mnt/sdcard      msdos noauto,user,noatime,async 0 0
/dev/mp3player_1 /mnt/mp3player1   vfat noauto,user,noatime,async 0 0
/dev/Cruzer1     /mnt/flashdrive1  vfat noauto,user,noatime,async 0 0
/dev/bigUSBdrive /mnt/bigdrive reiserfs noauto,user,noatime,async,notail  0 0
/dev/PocketDrive1 /mnt/pocket1 reiserfs noauto,user,noatime,async,notail 0 0
/dev/PocketDrive2 /mnt/pocket2 reiserfs noauto,user,noatime,async,notail 0 0


# NOTE: The next line is critical for boot!
proc			/proc		proc		defaults	0 0

# glibc 2.2 and above expects tmpfs to be mounted at /dev/shm for 
# POSIX shared memory (shm_open, shm_unlink).
# (tmpfs is a dynamically expandable/shrinkable ramdisk, and will
#  use almost no memory if not populated with files)
shm			/dev/shm	tmpfs	nodev,nosuid,noexec	0 0


Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/hda1              1208692    212956    946580  19% /
udev                     62464      2660     59804   5% /dev
/dev/hda6             37815936  24949736  11329424  69% /home
shm                      62464         0     62464   0% /dev/shm

-- 
Walter Dnes <waltdnes@waltdnes.org>

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Neil Bothwick]

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On Wed, 3 Mar 2010 12:52:55 +0100, Alex Schuster wrote:

> > The data I've seen indicates that ext2 is fastest, that's what I
> > use.  
> 
> I thought the small files of the portage tree especially profit from
> the notail option in reiserfs?

They benefit compared with using reiser with tail-packing.

> Did you change the block size?

I had to change both the block size and blocks per inode, otherwise I
would run out of inodes on a 1GB filesystem. You have to admire the
user-friendliness of ext!

> > There's no need for journalling on the portage tree, it's small enough
> > to fsck quickly and if it does get broken, reformat and resync.  
> 
> Would the journaling overhead be noticeable? 
> I also had used ext2 for my portage tree first, then I read somewhere
> that reiserfs would be the best. BTW, I have distfiles and pkgdir
> somewhere else, if not the fsck would not be so fast.

It's certainly noticeable compared with ext3. Many benchmarks do show
ext2 to be the fastest filesystem, probably because of the lack of
journalling overhead.

Like you, I have $DISTDIR and $PKGDIR elsewhere, those files really
should not be mixed in with the portage tree.

> Just for fun, I just copied my $PORTDIR into my tmpfs, emerge -DpN
> @system @world takes between 81 and 53 seconds. With reiserfs, I get
> 130 seconds first ($PORTDIR was unmounted first and mounted again to
> clear the caches), and 57 seconds in the second attempt.
> 
> I had expected that tmpfs would be even faster. I think I just keep it
> the way it is now.

The exact same thought occurred to me. With a local tree to sync from,
tmpfs seemed a good choice (you could sync it from /etc/conf.d/local) but
it seems like it is not worth bothering with. I'll try a reiser3
filesystem without tail packing to see if it beats ext2.


-- 
Neil Bothwick

Those who live by the sword get shot by those who don't.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 198 bytes --]

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Alex Schuster]

Neil Bothwick writes:

> On Wed, 3 Mar 2010 12:52:55 +0100, Alex Schuster wrote:
> > > The data I've seen indicates that ext2 is fastest, that's what I
> > > use.
> > 
> > I thought the small files of the portage tree especially profit from
> > the notail option in reiserfs?
> 
> They benefit compared with using reiser with tail-packing.

Oh my. I have it the other way around, and never even thought much about 
what this does.

> > Did you change the block size?
> 
> I had to change both the block size and blocks per inode, otherwise I
> would run out of inodes on a 1GB filesystem. You have to admire the
> user-friendliness of ext!

I only wished I could add more inodes after all are out, because this 
happens quite frequently to me. But yes, it's nice I can specify this at 
all.


> > > There's no need for journalling on the portage tree, it's small
> > > enough to fsck quickly and if it does get broken, reformat and
> > > resync.
> > 
> > Would the journaling overhead be noticeable?
> > I also had used ext2 for my portage tree first, then I read somewhere
> > that reiserfs would be the best. BTW, I have distfiles and pkgdir
> > somewhere else, if not the fsck would not be so fast.
> 
> It's certainly noticeable compared with ext3. Many benchmarks do show
> ext2 to be the fastest filesystem, probably because of the lack of
> journalling overhead.

When I saw some, it was maybe 15% difference, and that probably due to 
writes I assume. The portage tree is written during sync only, and then I 
do not care about speed. But would accessing lots and lots of small files 
be slowed down by journaling?

> Like you, I have $DISTDIR and $PKGDIR elsewhere, those files really
> should not be mixed in with the portage tree.
> 
> > Just for fun, I just copied my $PORTDIR into my tmpfs, emerge -DpN
> > @system @world takes between 81 and 53 seconds. With reiserfs, I get
> > 130 seconds first ($PORTDIR was unmounted first and mounted again to
> > clear the caches), and 57 seconds in the second attempt.
> > 
> > I had expected that tmpfs would be even faster. I think I just keep
> > it the way it is now.
> 
> The exact same thought occurred to me. With a local tree to sync from,
> tmpfs seemed a good choice (you could sync it from /etc/conf.d/local)
> but it seems like it is not worth bothering with.

I would need more memory for that, I'm not at amd64 yet. But I probably 
should migrate anyway, and get another 4GB of memory.

> I'll try a reiser3
> filesystem without tail packing to see if it beats ext2.

I backed up my portage tree, re-created the reiserfs partition, and 
mounted without notail option. The same emerge command now takes about 
three minutes... no, on 2nd try it's five. Hmm... ah, clementine is 
indexing files. Why does it do this, I did not change files. Oh, and it 
has indexed all of my /data/mp3, while I only gave it four subfolders to 
index. Why does no audio player just accept my choices for what the 
collection is, and add other stuff?

The next test gives 93 seconds, that's nice.

	Wonko

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Alex Schuster]

Alex Schuster writes:
> Neil Bothwick writes:
> > On Wed, 3 Mar 2010 12:52:55 +0100, Alex Schuster wrote:
> > > > The data I've seen indicates that ext2 is fastest, that's what I
> > > > use.
> > > 
> > > I thought the small files of the portage tree especially profit
> > > from the notail option in reiserfs?
> > 
> > They benefit compared with using reiser with tail-packing.
> 
> Oh my. I have it the other way around, and never even thought much
> about what this does.
> 
> > > Did you change the block size?
> > 
> > I had to change both the block size and blocks per inode, otherwise I
> > would run out of inodes on a 1GB filesystem. You have to admire the
> > user-friendliness of ext!
> 
> I only wished I could add more inodes after all are out, because this
> happens quite frequently to me. But yes, it's nice I can specify this
> at all.
> 
> > > > There's no need for journalling on the portage tree, it's small
> > > > enough to fsck quickly and if it does get broken, reformat and
> > > > resync.
> > > 
> > > Would the journaling overhead be noticeable?
> > > I also had used ext2 for my portage tree first, then I read
> > > somewhere that reiserfs would be the best. BTW, I have distfiles
> > > and pkgdir somewhere else, if not the fsck would not be so fast.
> > 
> > It's certainly noticeable compared with ext3. Many benchmarks do show
> > ext2 to be the fastest filesystem, probably because of the lack of
> > journalling overhead.
> 
> When I saw some, it was maybe 15% difference, and that probably due to
> writes I assume. The portage tree is written during sync only, and then
> I do not care about speed. But would accessing lots and lots of small
> files be slowed down by journaling?
> 
> > Like you, I have $DISTDIR and $PKGDIR elsewhere, those files really
> > should not be mixed in with the portage tree.
> > 
> > > Just for fun, I just copied my $PORTDIR into my tmpfs, emerge -DpN
> > > @system @world takes between 81 and 53 seconds. With reiserfs, I
> > > get 130 seconds first ($PORTDIR was unmounted first and mounted
> > > again to clear the caches), and 57 seconds in the second attempt.
> > > 
> > > I had expected that tmpfs would be even faster. I think I just keep
> > > it the way it is now.
> > 
> > The exact same thought occurred to me. With a local tree to sync
> > from, tmpfs seemed a good choice (you could sync it from
> > /etc/conf.d/local) but it seems like it is not worth bothering with.
> 
> I would need more memory for that, I'm not at amd64 yet. But I probably
> should migrate anyway, and get another 4GB of memory.
> 
> > I'll try a reiser3
> > filesystem without tail packing to see if it beats ext2.
> 
> I backed up my portage tree, re-created the reiserfs partition, and
> mounted without notail option. The same emerge command now takes about
> three minutes... no, on 2nd try it's five. Hmm... ah, clementine is
> indexing files. Why does it do this, I did not change files. Oh, and it
> has indexed all of my /data/mp3, while I only gave it four subfolders
> to index. Why does no audio player just accept my choices for what the
> collection is, and add other stuff?
> 
> The next test gives 93 seconds, that's nice.
> 
> 	Wonko

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Alex Schuster]

Alex Schuster writes:
> Neil Bothwick writes:
> > On Wed, 3 Mar 2010 12:52:55 +0100, Alex Schuster wrote:
> > > > The data I've seen indicates that ext2 is fastest, that's what I
> > > > use.
> > > 
> > > I thought the small files of the portage tree especially profit
> > > from the notail option in reiserfs?
> > 
> > They benefit compared with using reiser with tail-packing.
> 
> Oh my. I have it the other way around, and never even thought much
> about what this does.
> 
> > > Did you change the block size?
> > 
> > I had to change both the block size and blocks per inode, otherwise I
> > would run out of inodes on a 1GB filesystem. You have to admire the
> > user-friendliness of ext!
> 
> I only wished I could add more inodes after all are out, because this
> happens quite frequently to me. But yes, it's nice I can specify this
> at all.
> 
> > > > There's no need for journalling on the portage tree, it's small
> > > > enough to fsck quickly and if it does get broken, reformat and
> > > > resync.
> > > 
> > > Would the journaling overhead be noticeable?
> > > I also had used ext2 for my portage tree first, then I read
> > > somewhere that reiserfs would be the best. BTW, I have distfiles
> > > and pkgdir somewhere else, if not the fsck would not be so fast.
> > 
> > It's certainly noticeable compared with ext3. Many benchmarks do show
> > ext2 to be the fastest filesystem, probably because of the lack of
> > journalling overhead.
> 
> When I saw some, it was maybe 15% difference, and that probably due to
> writes I assume. The portage tree is written during sync only, and then
> I do not care about speed. But would accessing lots and lots of small
> files be slowed down by journaling?
> 
> > Like you, I have $DISTDIR and $PKGDIR elsewhere, those files really
> > should not be mixed in with the portage tree.
> > 
> > > Just for fun, I just copied my $PORTDIR into my tmpfs, emerge -DpN
> > > @system @world takes between 81 and 53 seconds. With reiserfs, I
> > > get 130 seconds first ($PORTDIR was unmounted first and mounted
> > > again to clear the caches), and 57 seconds in the second attempt.
> > > 
> > > I had expected that tmpfs would be even faster. I think I just keep
> > > it the way it is now.
> > 
> > The exact same thought occurred to me. With a local tree to sync
> > from, tmpfs seemed a good choice (you could sync it from
> > /etc/conf.d/local) but it seems like it is not worth bothering with.
> 
> I would need more memory for that, I'm not at amd64 yet. But I probably
> should migrate anyway, and get another 4GB of memory.
> 
> > I'll try a reiser3
> > filesystem without tail packing to see if it beats ext2.
> 
> I backed up my portage tree, re-created the reiserfs partition, and
> mounted without notail option. The same emerge command now takes about
> three minutes... no, on 2nd try it's five. Hmm... ah, clementine is
> indexing files. Why does it do this, I did not change files. Oh, and it
> has indexed all of my /data/mp3, while I only gave it four subfolders
> to index. Why does no audio player just accept my choices for what the
> collection is, and add other stuff?
> 
> The next test gives 93 seconds, that's nice.
> 
> 	Wonko
<

Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Alex Schuster]

Argh, sorry for the previous posts. I had some sort of Ctrl-lock, that is, 
the keyboard acted as if Ctrl was pressed all the time. Now I know that 
Ctrl+Enter is a shortcut to send an email. I accidentally closed some 
shells by pressing the D key.

I was able to get rid off it by switching to a text console with Alt-F1 
(the additional Ctrl key was also not needed) and back.


Alex Schuster writes:

> The next test gives 93 seconds, that's nice.

What is not so nice is that emerge -a --depclean took over half an hour of 
CPU time, needing half a gigabyte of memory. WOW.

	Wonko