[gentoo-user] lvm2/external partitions question

[gentoo-user] lvm2/external partitions question

[Mark Knecht]

Hi,
   My new A8N-E/AMD64 hardware came up the first time. SATA/DVD/CDRW
all seen. LiveCD boots fine. memtest86 has been running for the last
hour and looks good so far. All looks good so I'll start a Gentoo
install pretty soon.

   I'm looking at LVN2 for this install. The main drive is 250GB. I'm
wondering a couple of things:

1) Should use all of the drive, other than the boot and swap
partitions, for the main LVN partition and then let LVN subdivide it
as needs come up as per the Gentoo-wiki on LVN2? This would meen, as I
understand it, that there would never been more than real partitions
on the drive.

2) Possibly make the main install partition something like 50GB and
use the balance of the hard drive outside of LVM2? If I do this and
later add a new partition within LVM does that somehow change device
numbering (/dev/sdaX) on the external partitions?

   I don't know why I would do the latter, other than should LVM
become inoperable it seems that I could still get at the 200GB that
isn't within LVM's control. Since the hardware is new I don't know
anything about it's reliability yet and hate to go down a path where
data gets trapped in a few weeks if something dies.

QUESTION: Are there any performance differences between using LVM and
a standard partition?

QUESTION 2: does anythign about LVM2 beg for a 2005.1 LiveCD? Mine is 2005.0.

   Probably I'll do #1 and just live with it but if there's a better
way to do it I'd like to hear what and why.

Thanks,
Mark

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Re: [gentoo-user] lvm2/external partitions question

[W.Kenworthy]

My scheme is:
 100 M /boot on ext3 (I was going to store some other info there, but
its mostly "space" att)

 2G swap

 4G reiserfs with a complete, basic gentoo rescue install - if all goes
pear shaped, I have a backup including a functioning /boot on this
partition.  Particularly useful with things like a gateway: you can come
up on the rescue partition and provide near normal service/network
access while fixing the main problem in a chroot etc.  Maintenance of
this partition is done offline in a chroot so other than an occasional
test, its rarely run in its own right.

 4G / on reiserfs with /etc, /root etc

 remainder (200G is below, and on my main desktop system similarly
arranged I have 200G + an extra 60G drive) is all LVM
containing /home, /var, /tmp and /usr.

This system is mainly a LAMP server/gateway for a home network. it also
contains mostly file storage and backups in /home

moriah ~ # df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/hda5             3.8G  2.2G  1.6G  59% /
udev                  252M  2.6M  249M   2% /dev
cachedir              3.8G  2.2G  1.6G  59% /lib/splash/cache
/dev/vg1/usr           32G  5.9G   27G  19% /usr
/dev/vg1/var           48G  2.3G   46G   5% /var
/dev/vg1/tmp           16G   33M   16G   1% /tmp
/dev/vg1/opt          4.0G  169M  3.9G   5% /opt
/dev/vg1/home          77G   26G   52G  34% /home
none                  252M     0  252M   0% /dev/shm
/dev/hda1              92M   18M   69M  21% /boot
/dev/hda3             3.8G  1.7G  2.1G  46% /mnt/hda3
moriah ~ #

There are probably performance issues, but they  are not noticeable in
practise.  hdparm actually shows a slight speed advantage for the LVM
partitions, but there are also error messages so I dont really trust it!

BillK


On Mon, 2005-08-29 at 17:50 -0700, Mark Knecht wrote:
> Hi,
>    My new A8N-E/AMD64 hardware came up the first time. SATA/DVD/CDRW
> all seen. LiveCD boots fine. memtest86 has been running for the last
> hour and looks good so far. All looks good so I'll start a Gentoo
> install pretty soon.
> 
>    I'm looking at LVN2 for this install. The main drive is 250GB. I'm
> wondering a couple of things:
> 
> 1) Should use all of the drive, other than the boot and swap
> partitions, for the main LVN partition and then let LVN subdivide it
> as needs come up as per the Gentoo-wiki on LVN2? This would meen, as I
> understand it, that there would never been more than real partitions
> on the drive.
> 
> 2) Possibly make the main install partition something like 50GB and
> use the balance of the hard drive outside of LVM2? If I do this and
> later add a new partition within LVM does that somehow change device
> numbering (/dev/sdaX) on the external partitions?
> 
>    I don't know why I would do the latter, other than should LVM
> become inoperable it seems that I could still get at the 200GB that
> isn't within LVM's control. Since the hardware is new I don't know
> anything about it's reliability yet and hate to go down a path where
> data gets trapped in a few weeks if something dies.
> 
> QUESTION: Are there any performance differences between using LVM and
> a standard partition?
> 
> QUESTION 2: does anythign about LVM2 beg for a 2005.1 LiveCD? Mine is 2005.0.
> 
>    Probably I'll do #1 and just live with it but if there's a better
> way to do it I'd like to hear what and why.
> 
> Thanks,
> Mark
> 
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Re: [gentoo-user] lvm2/external partitions question

[Mark Knecht]

On 8/29/05, W.Kenworthy <billk@iinet.net.au> wrote:
> My scheme is:
>  100 M /boot on ext3 (I was going to store some other info there, but
> its mostly "space" att)
> 
>  2G swap
> 
>  4G reiserfs with a complete, basic gentoo rescue install - if all goes
> pear shaped, I have a backup including a functioning /boot on this
> partition.  Particularly useful with things like a gateway: you can come
> up on the rescue partition and provide near normal service/network
> access while fixing the main problem in a chroot etc.  Maintenance of
> this partition is done offline in a chroot so other than an occasional
> test, its rarely run in its own right.
> 
>  4G / on reiserfs with /etc, /root etc
> 
>  remainder (200G is below, and on my main desktop system similarly
> arranged I have 200G + an extra 60G drive) is all LVM
> containing /home, /var, /tmp and /usr.
> 
> This system is mainly a LAMP server/gateway for a home network. it also
> contains mostly file storage and backups in /home
> 
> moriah ~ # df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/hda5             3.8G  2.2G  1.6G  59% /
> udev                  252M  2.6M  249M   2% /dev
> cachedir              3.8G  2.2G  1.6G  59% /lib/splash/cache
> /dev/vg1/usr           32G  5.9G   27G  19% /usr
> /dev/vg1/var           48G  2.3G   46G   5% /var
> /dev/vg1/tmp           16G   33M   16G   1% /tmp
> /dev/vg1/opt          4.0G  169M  3.9G   5% /opt
> /dev/vg1/home          77G   26G   52G  34% /home
> none                  252M     0  252M   0% /dev/shm
> /dev/hda1              92M   18M   69M  21% /boot
> /dev/hda3             3.8G  1.7G  2.1G  46% /mnt/hda3
> moriah ~ #
> 
> There are probably performance issues, but they  are not noticeable in
> practise.  hdparm actually shows a slight speed advantage for the LVM
> partitions, but there are also error messages so I dont really trust it!
> 
> BillK
> 

Thanks Bill,
   That's very helpful. To test my understanding

/dev/hda1 - boot - 100M
/dev/hda2 - swap - 2G
/dev/hda3 - NOT CLEAR - the backup/rescue install?
/dev/hda4 - LVM - 200G
/dev/hda5 - root - 4G

So you've placed pretty much the bulk of the machine in LVM and it's
working well for you. That's cool.

   Could you possibly share a bit from your grub.conf file as well as
your fstab file? I think with that info I'd be pretty confident when I
do the build tomorrow morning.

Thanks,
Mark

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Re: [gentoo-user] lvm2/external partitions question

[W.Kenworthy]

/dev/hda3 is the backup/rescue.  What I did last time I built a system,
is used this to build a working system.  Put it into service,
adjust/configure until I am happy.  Create the LVM in prep for the main
install.  Copy the rescue system to the LVM and setup grub.  reboot into
the main and go from there.  The original is then available as a backup.
Unless a severe security vul exists, I dont fiddle with it until a major
kernel update occurs.

Grub is:
____________________________________
default 0
fallback 2
timeout 5

splashimage=(hd0,0)/grub/splash.xpm.gz
configfile=(hd0,0)/grub/grub.conf

title=Gentoo Sources (2.6.13-r7) resume
root (hd0,0)
kernel (hd0,0)/linux-2.6.13-rc7 root=/dev/hda5 splash=verbose vga=0x317
elevator=cfq gentoo=nodevfs resume2=swap:/dev/hda2

title=Gentoo Sources (2.6.13-r7) NOresume
root (hd0,0)
kernel (hd0,0)/linux-2.6.13-rc7 root=/dev/hda5 splash=verbose vga=0x317
elevator=cfq gentoo=nodevfs resume2=swap:/dev/hda2 noresume

...

title=Gentoo Sources (2.6.11-r9) RESCUE
root (hd0,0)
kernel (hd0,0)/linux-2.6.11-gentoo-r9 root=/dev/hda3 splash=verbose
elevator=cfq gentoo=nodevfs resume2=swap:/dev/hda2 noresume

__________________________________

I am using a patched for suspend2 kernel (vanilla here, but gentoo
sources when its available.  I do not use genkernel: it has caused me
too many problems in the past.

BillK





On Mon, 2005-08-29 at 21:28 -0700, Mark Knecht wrote:
> On 8/29/05, W.Kenworthy <billk@iinet.net.au> wrote:
> > My scheme is:
...
> 
> Thanks Bill,
>    That's very helpful. To test my understanding
> 
> /dev/hda1 - boot - 100M
> /dev/hda2 - swap - 2G
> /dev/hda3 - NOT CLEAR - the backup/rescue install?
> /dev/hda4 - LVM - 200G
> /dev/hda5 - root - 4G
> 
> So you've placed pretty much the bulk of the machine in LVM and it's
> working well for you. That's cool.
> 
>    Could you possibly share a bit from your grub.conf file as well as
> your fstab file? I think with that info I'd be pretty confident when I
> do the build tomorrow morning.
> 
> Thanks,
> Mark
> 
-- 
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Re: [gentoo-user] lvm2/external partitions question

[Dirk Heinrichs]

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Am Dienstag, 30. August 2005 06:28 schrieb ext Mark Knecht:
>    That's very helpful. To test my understanding
>
> /dev/hda1 - boot - 100M

Way too much.

> /dev/hda2 - swap - 2G

Can be on a logical volume, too.

> /dev/hda3 - NOT CLEAR - the backup/rescue install?

Why? Use the LiveCD.

> /dev/hda4 - LVM - 200G

> /dev/hda5 - root - 4G

Can also be on a logical volume, but needs an initrd/initramfs. 4G is too 
large, IMHO. Mine is 256M.

> So you've placed pretty much the bulk of the machine in LVM and it's
> working well for you. That's cool.

I've even placed _all_ of my machines on logical volumes (using EVMS), and 
it also works well.

>    Could you possibly share a bit from your grub.conf file as well as
> your fstab file? I think with that info I'd be pretty confident when I
> do the build tomorrow morning.

Partition table:
# fdisk -l /dev/hda

Disk /dev/hda: 10.0 GB, 10005037056 bytes
240 heads, 63 sectors/track, 1292 cylinders
Units = cylinders of 15120 * 512 = 7741440 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1           8       60448+  83  Linux
/dev/hda2               9        1292     9707040   83  Linux


Everything below resides on hda2.

/etc/fstab:

/dev/evms/root          /                       reiserfs        defaults,acl    
0 1
/dev/evms/usr           /usr                    reiserfs        defaults,acl    
0 2
/dev/evms/var           /var                    reiserfs        defaults,acl    
0 2
/dev/evms/opt           /opt                    reiserfs        defaults,acl    
0 2
/dev/evms/build         /gentoo/build           reiserfs        defaults,acl    
0 2
/dev/evms/distfiles     /gentoo/distfiles       reiserfs        defaults,acl    
0 2
/dev/evms/swap          none                    swap            sw              
0 0

Sizes:
# df -h|grep evms
/dev/evms/root        256M  132M  125M  52% /
/dev/evms/usr         3.0G  2.6G  452M  86% /usr
/dev/evms/var         384M  210M  174M  55% /var
/dev/evms/opt         512M  497M   16M  97% /opt
/dev/evms/build       2.7G  1.5G  1.2G  57% /gentoo/build
/dev/evms/distfiles   1.5G  1.4G  127M  92% /gentoo/distfiles

Note that this machine gets $HOME from NFS, so I don't list it here. I would 
usually create a separate volume for each users home dir, so that I don't 
have to care about quota (if needed).

grub.conf:
title Gentoo Linux 2.6
        kernel /vmlinuz-2.6.12.3 root=/dev/ram0 realroot=/dev/evms/root 
vga=794
        initrd=/initrd-2.6.12.3.gz

Note that I use a self-made initrd, which activates the EVMS volumes (needed 
because / is an EVMS volume, too), does a pivot_root from root to realroot 
and then starts up the real thing.

Bye...

	Dirk
-- 
Dirk Heinrichs          | Tel:  +49 (0)162 234 3408
Configuration Manager   | Fax:  +49 (0)211 47068 111
Capgemini Deutschland   | Mail: dirk.heinrichs@capgemini.com
Hambornerstraße 55      | Web:  http://www.capgemini.com
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Re: [gentoo-user] lvm2/external partitions question

[W.Kenworthy]

Comments inline:

moriah ~ # df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/hda5             3.8G  2.2G  1.6G  59% /
udev                  252M  2.6M  249M   2% /dev
cachedir              3.8G  2.2G  1.6G  59% /lib/splash/cache
/dev/vg1/usr           32G  5.9G   27G  19% /usr
/dev/vg1/var           48G  2.3G   46G   5% /var
/dev/vg1/tmp           16G   33M   16G   1% /tmp
/dev/vg1/opt          4.0G  169M  3.9G   5% /opt
/dev/vg1/home          77G   26G   52G  34% /home
none                  252M     0  252M   0% /dev/shm
/dev/hda1              92M   18M   69M  21% /boot
/dev/hda3             3.8G  1.7G  2.1G  46% /mnt/hda3

On Tue, 2005-08-30 at 07:49 +0200, Dirk Heinrichs wrote:
> Am Dienstag, 30. August 2005 06:28 schrieb ext Mark Knecht:
> >    That's very helpful. To test my understanding
> >
> > /dev/hda1 - boot - 100M
> 
> Way too much.
only if you are using for nothing else but kernels - as mentioned in my
prev. I intended using it for storage as well as booting.

> > /dev/hda2 - swap - 2G
> 
> Can be on a logical volume, too.
> 
I have seen warnings against doing this due to poor performance

> > /dev/hda3 - NOT CLEAR - the backup/rescue install?
> 
> Why? Use the LiveCD.
> 
Some machines dont have a CD.  A liveCD also doesnt run squid with my
setup, a mailfiltering gateway or my particular firewall configuration
and so on so its either useless, or means extensive downtime to
reconfigure.  For pure rescue, or a limited desktop a liveCD is fine
(and generally knoppix is superior anyway for a desktop)
only if you are using for nothing else but kernels - as mentioned in my
prev. I intended using it for storage as well as booting.

> > /dev/hda4 - LVM - 200G
> 
> > /dev/hda5 - root - 4G
> 
> Can also be on a logical volume, but needs an initrd/initramfs. 4G is too 
> large, IMHO. Mine is 256M.
> 
As you can see, I already use 2.2G of the root (and 2.9G on another
system), and sometimes much more - so 256M isnt going to get me far!
Set it to your own particular requirements.  I dont use initrd's - too
flakey, extra work thats not needed in most cases.  I decided in my
early experiments to limit LVM for data on the partitions that cause me
grief with space so most of the root partitions including /etc and /lib
are on a base filesystem (/)  This can simplify working on the system.
It is possible to use LVM for nearly everything, but there's extra
complexity, and warnings about some configurations.

Small roots used to be the way in the old days, but the number of
machines that crashed due to running out of root space were legion!

> > So you've placed pretty much the bulk of the machine in LVM and it's
> > working well for you. That's cool.
> 
> I've even placed _all_ of my machines on logical volumes (using EVMS), and 
> it also works well.
> 
> >    Could you possibly share a bit from your grub.conf file as well as
> > your fstab file? I think with that info I'd be pretty confident when I
> > do the build tomorrow morning.
> 
> Partition table:
> # fdisk -l /dev/hda
> 
> Disk /dev/hda: 10.0 GB, 10005037056 bytes
> 240 heads, 63 sectors/track, 1292 cylinders
> Units = cylinders of 15120 * 512 = 7741440 bytes
> 
>    Device Boot      Start         End      Blocks   Id  System
> /dev/hda1   *           1           8       60448+  83  Linux
> /dev/hda2               9        1292     9707040   83  Linux
> 
> 
> Everything below resides on hda2.
> 
> /etc/fstab:
> 
> /dev/evms/root          /                       reiserfs        defaults,acl    
> 0 1
> /dev/evms/usr           /usr                    reiserfs        defaults,acl    
> 0 2
> /dev/evms/var           /var                    reiserfs        defaults,acl    
> 0 2
> /dev/evms/opt           /opt                    reiserfs        defaults,acl    
> 0 2
> /dev/evms/build         /gentoo/build           reiserfs        defaults,acl    
> 0 2
> /dev/evms/distfiles     /gentoo/distfiles       reiserfs        defaults,acl    
> 0 2
> /dev/evms/swap          none                    swap            sw              
> 0 0
> 
> Sizes:
> # df -h|grep evms
> /dev/evms/root        256M  132M  125M  52% /
> /dev/evms/usr         3.0G  2.6G  452M  86% /usr
> /dev/evms/var         384M  210M  174M  55% /var
> /dev/evms/opt         512M  497M   16M  97% /opt
> /dev/evms/build       2.7G  1.5G  1.2G  57% /gentoo/build
> /dev/evms/distfiles   1.5G  1.4G  127M  92% /gentoo/distfiles
> 
> Note that this machine gets $HOME from NFS, so I don't list it here. I would 
> usually create a separate volume for each users home dir, so that I don't 
> have to care about quota (if needed).
> 
> grub.conf:
> title Gentoo Linux 2.6
>         kernel /vmlinuz-2.6.12.3 root=/dev/ram0 realroot=/dev/evms/root 
> vga=794
>         initrd=/initrd-2.6.12.3.gz
> 
> Note that I use a self-made initrd, which activates the EVMS volumes (needed 
> because / is an EVMS volume, too), does a pivot_root from root to realroot 
> and then starts up the real thing.
> 
> Bye...
> 
> 	Dirk
-- 
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Re: [gentoo-user] lvm2/external partitions question

[Dirk Heinrichs]

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Am Dienstag, 30. August 2005 08:49 schrieb ext W.Kenworthy:
> Comments inline:
>
> moriah ~ # df -h
> Filesystem            Size  Used Avail Use% Mounted on
> udev                  252M  2.6M  249M   2% /dev

Hmm, mine takes 116k, how comes your /dev uses 2.6M?

> cachedir              3.8G  2.2G  1.6G  59% /lib/splash/cache

This looks to be the same as /, what is it good for, could you explain this?

> /dev/vg1/usr           32G  5.9G   27G  19% /usr
> /dev/vg1/var           48G  2.3G   46G   5% /var

I doubt you'll ever get them filled.

> /dev/vg1/tmp           16G   33M   16G   1% /tmp

I use tmpfs for this, but that really depends.

> /dev/vg1/home          77G   26G   52G  34% /home

As said before I prefer per-user volumes (and use the automounter to mount 
them on demand).

> On Tue, 2005-08-30 at 07:49 +0200, Dirk Heinrichs wrote:
> > Am Dienstag, 30. August 2005 06:28 schrieb ext Mark Knecht:
> > >    That's very helpful. To test my understanding
> > >
> > > /dev/hda1 - boot - 100M
> >
> > Way too much.
>
> only if you are using for nothing else but kernels - as mentioned in my
> prev. I intended using it for storage as well as booting.
>
> > > /dev/hda2 - swap - 2G
> >
> > Can be on a logical volume, too.
>
> I have seen warnings against doing this due to poor performance

Do you have any real numbers?

> > > /dev/hda3 - NOT CLEAR - the backup/rescue install?
> >
> > Why? Use the LiveCD.
>
> Some machines dont have a CD.  A liveCD also doesnt run squid with my
> setup, a mailfiltering gateway or my particular firewall configuration
> and so on so its either useless, or means extensive downtime to
> reconfigure.  For pure rescue, or a limited desktop a liveCD is fine
> (and generally knoppix is superior anyway for a desktop)
> only if you are using for nothing else but kernels - as mentioned in my
> prev. I intended using it for storage as well as booting.

OK, depending on the use of the machine, it may be useful, but Mark didn't 
tell. So I wanted to show another way.

> > > /dev/hda5 - root - 4G
> >
> > Can also be on a logical volume, but needs an initrd/initramfs. 4G is
> > too large, IMHO. Mine is 256M.
>
> As you can see, I already use 2.2G of the root (and 2.9G on another
> system), and sometimes much more - so 256M isnt going to get me far!

I wonder what else to put on / that couldn't be on a separate volume? / has 
everything to get things set up, nothing more nothing less. If I'd need a 
rescue system, I would rsync my current / to a separate volume/partition 
and change one line in /etc/fstab on the clone and add an entry for it to 
grub conf.

> Set it to your own particular requirements.  I dont use initrd's - too
> flakey, extra work thats not needed in most cases.  I decided in my
> early experiments to limit LVM for data on the partitions that cause me
> grief with space so most of the root partitions including /etc and /lib
> are on a base filesystem (/)  This can simplify working on the system.
> It is possible to use LVM for nearly everything, but there's extra
> complexity, and warnings about some configurations.
>
> Small roots used to be the way in the old days, but the number of
> machines that crashed due to running out of root space were legion!

As you can see below, even my 256M are too much, only 52% are used and it 
didn't change much for years. Even if I would run out of space on /, I 
could simply grow it (and since it's a lv, with reiserfs on it, it can be 
done online).

> > Sizes:
> > # df -h|grep evms
> > /dev/evms/root        256M  132M  125M  52% /

Bye...

	Dirk
-- 
Dirk Heinrichs          | Tel:  +49 (0)162 234 3408
Configuration Manager   | Fax:  +49 (0)211 47068 111
Capgemini Deutschland   | Mail: dirk.heinrichs@capgemini.com
Hambornerstraße 55      | Web:  http://www.capgemini.com
D-40472 Düsseldorf      | ICQ#: 110037733
GPG Public Key C2E467BB | Keyserver: www.keyserver.net

[-- Attachment #2: Type: application/pgp-signature, Size: 190 bytes --]

Re: [gentoo-user] lvm2/external partitions question

[W.Kenworthy]

On Tue, 2005-08-30 at 09:38 +0200, Dirk Heinrichs wrote:
> Am Dienstag, 30. August 2005 08:49 schrieb ext W.Kenworthy:
> > Comments inline:
> >
> > moriah ~ # df -h
> > Filesystem            Size  Used Avail Use% Mounted on
> > udev                  252M  2.6M  249M   2% /dev
> 
> Hmm, mine takes 116k, how comes your /dev uses 2.6M?
> 
everything thats not on a LVM volume sits here.  the biggest
is /root/.ccache (<800M, easily moved elsewhere) and /lib/modules

> > cachedir              3.8G  2.2G  1.6G  59% /lib/splash/cache
> 
> This looks to be the same as /, what is it good for, could you explain this?
> 
Its used by fbsplash - never looked at why

> > /dev/vg1/usr           32G  5.9G   27G  19% /usr
> > /dev/vg1/var           48G  2.3G   46G   5% /var
> 
> I doubt you'll ever get them filled.
> 
I have filled them in the past: my desktop is currently sitting at 74%
for both, but I recently went mad archiving to make room.

> > /dev/vg1/tmp           16G   33M   16G   1% /tmp
> 
> I use tmpfs for this, but that really depends.
> 
I have done that in the past - but I found sometimes I just had to have
the room (zipping 2G plus archives for instance)

> > /dev/vg1/home          77G   26G   52G  34% /home
> 
> As said before I prefer per-user volumes (and use the automounter to mount 
> them on demand).
> 
extra complexity - I dont need remote mounts, and I am the main user.
If you use an automount on the same machine Ive gotta ask "why bother".
In my experience automount is just another thing that can and sometimes
does go wrong so it has to be justified.

Experience shows me that a single partition is almost maintenance free.
If you fill a disk, it does come to a halt but its easily fixed.  Ive
found inadequate a swap more serious problem.

Ive found that maintenance usually occurs far more often on
multi-partition systems simply because space that could be used is not
accessible.  Multi-partitions on the other hand always waste space
necessitating solutions like LVM.  For me LVM gives the advantage in
that I can add space (extra disks) whenever I like and fill it without
having to go through major pain.  In the light of experience, I am not
sure I will go for multi-partitions on my next server as laptops/small
desktop systems I run/have run seem better without it, but I will
definitely be going LVM.  I am sure that if I had a number of regular
users, a separate /home partition wold be useful but I think that the
old idea of partitioning everything is actually more wasteful/nearly
useless on modern systems.

BillK

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Re: [gentoo-user] lvm2/external partitions question

[Dirk Heinrichs]

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Am Dienstag, 30. August 2005 10:25 schrieb ext W.Kenworthy:
> On Tue, 2005-08-30 at 09:38 +0200, Dirk Heinrichs wrote:
> > Am Dienstag, 30. August 2005 08:49 schrieb ext W.Kenworthy:
> > > Comments inline:
> > >
> > > moriah ~ # df -h
> > > Filesystem            Size  Used Avail Use% Mounted on
> > > udev                  252M  2.6M  249M   2% /dev
> >
> > Hmm, mine takes 116k, how comes your /dev uses 2.6M?
>
> everything thats not on a LVM volume sits here.  the biggest
> is /root/.ccache (<800M, easily moved elsewhere) and /lib/modules

I was refering to the "udev" line (116K vs. 2.6M in /dev).

> > > /dev/vg1/tmp           16G   33M   16G   1% /tmp
> >
> > I use tmpfs for this, but that really depends.
>
> I have done that in the past - but I found sometimes I just had to have
> the room (zipping 2G plus archives for instance)

As I said, that depends.

> > > /dev/vg1/home          77G   26G   52G  34% /home
> >
> > As said before I prefer per-user volumes (and use the automounter to
> > mount them on demand).
>
> extra complexity - I dont need remote mounts, and I am the main user.
> If you use an automount on the same machine Ive gotta ask "why bother".

Because a filesystem that isn't mounted when not needed can't be corrupted 
or its contents accidentally deleted. I tend to only mount things when they 
are really needed. I also use the automounter for removeable media and the 
Gentoo specific stuff like distfiles and building 
(/gentoo/distfiles, /gentoo/build).

Bye...

	Dirk
-- 
Dirk Heinrichs          | Tel:  +49 (0)162 234 3408
Configuration Manager   | Fax:  +49 (0)211 47068 111
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Re: [gentoo-user] lvm2/external partitions question

[Chris Cox]

On Monday 29 August 2005 07:50 pm, Mark Knecht wrote:
> Hi,
>    My new A8N-E/AMD64 hardware came up the first time. SATA/DVD/CDRW
> all seen. LiveCD boots fine. memtest86 has been running for the last
> hour and looks good so far. All looks good so I'll start a Gentoo
> install pretty soon.
>
>    I'm looking at LVN2 for this install. The main drive is 250GB. I'm
> wondering a couple of things:
>
> 1) Should use all of the drive, other than the boot and swap
> partitions, for the main LVN partition and then let LVN subdivide it
> as needs come up as per the Gentoo-wiki on LVN2? This would meen, as I
> understand it, that there would never been more than real partitions
> on the drive.

You can use it all or into chunks of 20GB each as the how-to suggests; either 
way is fine.  When you create your partitions like /usr, /opt, /home, etc. 
what I would suggest is give them 5GB or so each. Then when you need more 
space you can run /sbin/lvresize to give it more space and then adjust the 
file system with resize_reiserfs (if your using reiserfs), to resize them as 
needed.  I use reiserfs on everything and I've done it on live file systems 
like /usr, /var, /home without needed to unmount them.    I've been using 
LVM2 for a couple months now and so far I'm pretty pleased with it.

Anyway, just my 2 cents.. 

-- 
Chris
Linux 2.6.12-gentoo-r9 i686 AMD Athlon(tm) XP 
 00:10:21 up  5:29,  6 users,  load average: 1.68, 1.58, 1.42
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Re: [gentoo-user] lvm2/external partitions question

[Alvin A ONeal Jr]

[-- Attachment #1: Type: text/plain, Size: 563 bytes --]

> You can use it all or into chunks of 20GB each as the how-to suggests;

I agree. I think the biggest reason to use the whole drive as one 
logical partition would be if you had dual SATA and you were striping.

It's nice to have that extra space available as non-LVM2 just in case 
you need it. And since we are talking about LVM2, if you have a few 
partitions you can always manipulate them at will anyhow.


-- 
8^)
Laterz-
~Alvin
http://CoolAJ86.Havenite.net

---
Computers are like air conditioners - They can't do their job properly 
if you open windows.

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n:ONeal;Alvin
adr;dom:;;34 Fletcher Lane;Shelburne;VT;05482
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tel;home:1.802.985.5277
tel;cell:1.802.578.0599
note;quoted-printable:DoB: 19860616=0D=0A=
	
x-mozilla-html:FALSE
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Re: [gentoo-user] lvm2/external partitions question

[Neil Bothwick]

[-- Attachment #1: Type: text/plain, Size: 1865 bytes --]

On Mon, 29 Aug 2005 17:50:15 -0700, Mark Knecht wrote:

>    I'm looking at LVN2 for this install. The main drive is 250GB. I'm
> wondering a couple of things:

I've ben using LVM2 on my AMD64 box since I built it.

> 1) Should use all of the drive, other than the boot and swap
> partitions, for the main LVN partition and then let LVN subdivide it
> as needs come up as per the Gentoo-wiki on LVN2? This would meen, as I
> understand it, that there would never been more than real partitions
> on the drive.

I have /boot, swap and / on normal partitions, everything else on LVM. /
is only 300MB, as /usr is on an LVM2 partition, /var and /opt are bound
to directories in /usr. I kow I could put / on LVM, but that requires an
initrd, which adds unnecessary complication IMO.

> 2) Possibly make the main install partition something like 50GB and
> use the balance of the hard drive outside of LVM2? If I do this and
> later add a new partition within LVM does that somehow change device
> numbering (/dev/sdaX) on the external partitions?

LVM uses its own partition naming. As far as the /dev/sda is concerned,
there are only four partitions in my setup. As someone else has already
suggested, make your partitions within LVM no larger than you think
you'll need, because it is so easy to enlarge them later. Most
filesystems can be enlarged while still mounted, while shrinking a
filesystem either requires it to be unmounted or is impossible depending
on your filesystem.

> QUESTION: Are there any performance differences between using LVM and
> a standard partition?

Not that I've noticed.

> QUESTION 2: does anythign about LVM2 beg for a 2005.1 LiveCD? Mine is
> 2005.0.

I installed it with a 2004.x CD, so I'm sure 2005.0 should be fine.


-- 
Neil Bothwick

If you like this tagline, call 1-800-TAGS'R'US

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Re: [gentoo-user] lvm2/external partitions question

[Mark Knecht]

Thanks Neil

On 8/30/05, Neil Bothwick <neil@digimed.co.uk> wrote:
> On Mon, 29 Aug 2005 17:50:15 -0700, Mark Knecht wrote:
> 
> >    I'm looking at LVN2 for this install. The main drive is 250GB. I'm
> > wondering a couple of things:
> 
> I've ben using LVM2 on my AMD64 box since I built it.
> 
> > 1) Should use all of the drive, other than the boot and swap
> > partitions, for the main LVN partition and then let LVN subdivide it
> > as needs come up as per the Gentoo-wiki on LVN2? This would meen, as I
> > understand it, that there would never been more than real partitions
> > on the drive.
> 
> I have /boot, swap and / on normal partitions, everything else on LVM. /
> is only 300MB, as /usr is on an LVM2 partition, /var and /opt are bound
> to directories in /usr. I kow I could put / on LVM, but that requires an
> initrd, which adds unnecessary complication IMO.

OK, so if

sda1 == /boot
sda2 == swap
sda3 == /

are on 'normal' partitions, then is LVM2 your last of 4 partitions or
is it in an extended partition to allow for other things later on the
drive?

I was considering making the 4th partition extended, placing LVM2 on
sda5, if that will work, and having one more partition that was
possibly FAT32 for transfer to my windows boxes if the need arises.

> 
> > 2) Possibly make the main install partition something like 50GB and
> > use the balance of the hard drive outside of LVM2? If I do this and
> > later add a new partition within LVM does that somehow change device
> > numbering (/dev/sdaX) on the external partitions?
> 
> LVM uses its own partition naming. As far as the /dev/sda is concerned,
> there are only four partitions in my setup. As someone else has already
> suggested, make your partitions within LVM no larger than you think
> you'll need, because it is so easy to enlarge them later. Most
> filesystems can be enlarged while still mounted, while shrinking a
> filesystem either requires it to be unmounted or is impossible depending
> on your filesystem.

So I think this says LVM2 is on a normal, non-extended, partition at
sda4 but just checking.

Thanks for your insights,
Mark

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Re: [gentoo-user] lvm2/external partitions question

[Neil Bothwick]

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On Tue, 30 Aug 2005 15:03:49 -0700, Mark Knecht wrote:

> > I have /boot, swap and / on normal partitions, everything else on
> > LVM. / is only 300MB, as /usr is on an LVM2 partition, /var and /opt
> > are bound to directories in /usr. I kow I could put / on LVM, but
> > that requires an initrd, which adds unnecessary complication IMO.
> 
> OK, so if
> 
> sda1 == /boot
> sda2 == swap
> sda3 == /
> 
> are on 'normal' partitions, then is LVM2 your last of 4 partitions or
> is it in an extended partition to allow for other things later on the
> drive?

They're on RAID partitions now, but all of those are extended. Before I
added the second drive, they were directly on extended partitions. I never
use primary partitions on Linux-only boxes, I don't see the point is
adding another limitation.

It was

sda5 - /boot
sda6 - swap
sda7 - /
sda8 - LVM

If you're concerned that you may need non-LVM space later, leave a gap
between 7 and 8. That way you have the choice later of extending / or
adding another partition and adding it to LVM.


-- 
Neil Bothwick

Q. How many mice does it take to screw in a light bulb?
A. Only two - but it's difficult to get them in there.

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Re: [gentoo-user] lvm2/external partitions question

[Mark Knecht]

On 8/30/05, Neil Bothwick <neil@digimed.co.uk> wrote:
> On Tue, 30 Aug 2005 15:03:49 -0700, Mark Knecht wrote:
> 
> > > I have /boot, swap and / on normal partitions, everything else on
> > > LVM. / is only 300MB, as /usr is on an LVM2 partition, /var and /opt
> > > are bound to directories in /usr. I kow I could put / on LVM, but
> > > that requires an initrd, which adds unnecessary complication IMO.
> >
> > OK, so if
> >
> > sda1 == /boot
> > sda2 == swap
> > sda3 == /
> >
> > are on 'normal' partitions, then is LVM2 your last of 4 partitions or
> > is it in an extended partition to allow for other things later on the
> > drive?
> 
> They're on RAID partitions now, but all of those are extended. Before I
> added the second drive, they were directly on extended partitions. I never
> use primary partitions on Linux-only boxes, I don't see the point is
> adding another limitation.
> 
> It was
> 
> sda5 - /boot
> sda6 - swap
> sda7 - /
> sda8 - LVM
> 
> If you're concerned that you may need non-LVM space later, leave a gap
> between 7 and 8. That way you have the choice later of extending / or
> adding another partition and adding it to LVM.
> 

Thanks Neil. Very interesting.

I seem to be having too much trouble here getting LVM2 to set up. I'm
getting error messages and it wouldn't set up the user directory at
all. I don't know what's the matter yet.

As I'm somewhat anxious to get the machine running at all (I have some
PCI card issues I want to test) I'm going to do a quick install much
as BillK did where I'll just use 10GB for now and put everything
except boot in there. I'll bring the machine up and see how it goes.
After that I'll revisit the LVM2 stuff.

thanks for your help.

Cheers,
Mark

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