[gentoo-user] Advice about setting up split home directory

[gentoo-user] Advice about setting up split home directory

[Alan E. Davis]

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Thanks to advice on this list I have a reasonably stable system now, and
it's time to get hands dirty.   I have more GB of collected files than I can
fit into my ~/ home directory, so I am planning to link several partitions
to ~/ in an effort to organize this mass.

1.  How could one reasonably link a subdir of a partition as a subdir or
folder of one's ~/, for example, /dev/sdd3/VIDEO (partition on that
partition called VIDEO) as a subdirectory, ~/VIDEO?  I want ~/VIDEO to
behave identically as it would if it were on the same partition as ~/ .  At
least to the greatest extent possible.  I have seen some arcane arrangement
somewhere, but to what extent is that necessary to do?  I would rather avoid
having to mount the entire parition as a subdir, and then have to access,
for example, ~/ARCHIVE/VIDEO.

2.  As an aside, Nautllus (~/amd64 Gnome overlay, version 2.23.5.1) behavior
differs from that in Ubuntu. I have resisted the use of a GUI file manager
for a long time, except for a few tasks, and especially I have avoided
nautilus as a tool for moving files around the system.  The availability of
bookmarks in the sidepane is highly useful, however, and I've gotten used
to it.  Can I remove the display of ~/media/* from the sidepanel?  This has
enabled me to organize my system much more effectively.  Thunar is more to
my taste in this way, but nautilus has other useful features, including it
is integrated with gnome.

Thank you for any advice.  Also thanks to the list for past helpful advice.


Alan

-- 
Alan Davis

"It's never a matter of liking or disliking ..."
---Santa Ynez Chumash Medicine Man

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Re: [gentoo-user] Advice about setting up split home directory

[b.n.]

Alan E. Davis ha scritto:
> Thanks to advice on this list I have a reasonably stable system now, and 
> it's time to get hands dirty.   I have more GB of collected files than I 
> can fit into my ~/ home directory, so I am planning to link several 
> partitions to ~/ in an effort to organize this mass.
> 
> 1.  How could one reasonably link a subdir of a partition as a subdir or 
> folder of one's ~/, for example, /dev/sdd3/VIDEO (partition on that 
> partition called VIDEO) as a subdirectory, ~/VIDEO?  I want ~/VIDEO to 
> behave identically as it would if it were on the same partition as ~/ .  
> At least to the greatest extent possible.  I have seen some arcane 
> arrangement somewhere, but to what extent is that necessary to do?  I 
> would rather avoid having to mount the entire parition as a subdir, and 
> then have to access, for example, ~/ARCHIVE/VIDEO.

What's wrong with using symbolic links?

m.

Re: [gentoo-user] Advice about setting up split home directory

[Volker Armin Hemmann]

On Sonntag, 3. August 2008, Alan E. Davis wrote:
> Thanks to advice on this list I have a reasonably stable system now, and
> it's time to get hands dirty.   I have more GB of collected files than I
> can fit into my ~/ home directory, so I am planning to link several
> partitions to ~/ in an effort to organize this mass.
>
> 1.  How could one reasonably link a subdir of a partition as a subdir or
> folder of one's ~/, for example, /dev/sdd3/VIDEO (partition on that
> partition called VIDEO) as a subdirectory, ~/VIDEO?  I want ~/VIDEO to
> behave identically as it would if it were on the same partition as ~/ .  At
> least to the greatest extent possible.  I have seen some arcane arrangement
> somewhere, but to what extent is that necessary to do?  I would rather
> avoid having to mount the entire parition as a subdir, and then have to
> access, for example, ~/ARCHIVE/VIDEO.

man mount, also google for 'bind' mounting. 

>
> 2.  As an aside, Nautllus (~/amd64 Gnome overlay, version 2.23.5.1)
> behavior differs from that in Ubuntu. 

because ubuntu patches A LOT. Ubuntu-gnome is not gnome.

Re: [gentoo-user] Advice about setting up split home directory

[Alan E. Davis]

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On Sun, Aug 3, 2008 at 11:17 PM, Volker Armin Hemmann <
volker.armin.hemmann@tu-clausthal.de> wrote:

>
>
> man mount, also google for 'bind' mounting.
>

Thank you.  That was it.  IN answer to another query, as to why not symlink,
I cannot point to a particular behavior, but I have found that symlinks do
not behave in all situations like real hardlinks.  What I want it something
like a hardlink to a directory.

I think this may be possible with bind mounting.

One major problem with nautilus or any other GUI file manager---in fact
many, many GUI programs that rely on mouse input primarily---has been the
loss of subtler capabilities like hard link.  I've been looking at using
hardlinks to organize my literature collection.  A single paper may belong
equally in several categories.  Or for photos, to go beyond, say, catalogs
in gthumbs: catalogs are possibly lost in an upgrade or minor accident.

 I'd be interested in seeing particular examples of the use of bind mounts
for the purposes I propose.  Reiterating:

   - mounting a directory from another tree with a full status in all
respects as a directory on the current tree.
   - mounting a directory in several places.   (A subdirectory of
microscopical images and another subdirectory of notes can be linked
together in the same directory under the specific project or organism under
study).

Perhaps a more skilled approach to the use of symlinks would serve the same
purpose more directly?

Thank you again for the input.

Alan



-- 
Alan Davis

"It's never a matter of liking or disliking ..."
---Santa Ynez Chumash Medicine Man

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Re: [gentoo-user] Advice about setting up split home directory

[Josh Cepek]

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Alan E. Davis wrote:
> Thanks to advice on this list I have a reasonably stable system now, and 
> it's time to get hands dirty.   I have more GB of collected files than I 
> can fit into my ~/ home directory, so I am planning to link several 
> partitions to ~/ in an effort to organize this mass.

Personally I'd suggest using LVM for this, although migrating to LVM 
would require you to back up your current filesystems (such as creating 
a stage 4 as described on the gentoo-wiki), reformatting your 
filesystems to LVM, and then un-tarring back to the LVM system.  I'm not 
sure if that's more work than you bargained for, but LVM has some 
fantastic features that prevent these sort of "out of space" issues:

1) You can leave some hard disk space in the Volume Group (VG) initially 
unallocated to Logical Volumes (LV's) and then add the unallocated space 
later to an LV (and its underlying filesystem) when it starts to become 
full.  This ability to "grow" an LV and the underlying filesystem can 
happen while the filesystem is online and in-use.

2) You can shrink LV's as well, although they need to be unmounted first.

3) You can easily migrate between hard drives while the system is online 
by moving LV's from one Physical Volume (PV) (eg: a hard disk) to another.

4) You can add multiple hard drives to an LVM Volume Group (VG - 
essentially a collection of PV's) and use the storage space from both 
drives to allocate space to an LV.

LVM is worth a look, at least to understand some of its benefits.  I 
typically set my root partition at about 512 MB and then create LVM 
partitions for /home, /usr, /opt, and /var. (You could do the same for 
/tmp, but I use tmpfs for that.)  It's possible to do LVM on the / 
partition, but that requires an initrd to work properly.


-- 
Josh


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Re: [gentoo-user] Advice about setting up split home directory

[Norberto Bensa]

Quoting Josh Cepek <josh.cepek@usa.net>:

> Personally I'd suggest using LVM for this

++

> 1)

++

> 2)

++

> 3) You can easily migrate between hard drives while the system is
> online by moving LV's from one Physical Volume (PV) (eg: a hard disk)
> to another.

--!!

Have you ever tried that? I've almost killed both hard drives doing an  
on-line migration to a bigger HD. I wouldn't recommend it.


>
> 4)

++

> LVM is worth a look,

++!!!


> /tmp, but I use tmpfs for that.)  It's possible to do LVM on the /
> partition, but that requires an initrd to work properly.
>
> Josh

You can use genkernel for that. Just configure your kernel as always,  
adding initrd features and then:

genkernel --lvm [your-options]

Easy.


Regards,
Norberto

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Re: [gentoo-user] Advice about setting up split home directory

[Alan E. Davis]

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Norberto and  Josh:

Thank you for the suggestion.  It's on the back burner.  I have the space to
experiment with it now.  I have balked for the time being on basis of,
partly, my need to be able to swap drives in and out, and have it clear in
mind which partitions belong to what.  Also my main drive is a 10000 RPM
faster drive, and I'd like to keep the partitions or directories that are
mainly for storage separated.  I really do notice a difference in the
performance of the drive.  this is somewhat of a conundrum: how to keep the
current projects focused on the faster drive.

Interestingly (to me) while I carefully planned for swap on the faster
drive, since I moved to 2GB of RAM, I think I've only touched swap two or
three times, and then only passingly!

I definitely wouldn't want to put / into LVM.

If I do LVM it will be the easy way, the most clearcut way.

Alan



On Mon, Aug 4, 2008 at 1:59 PM, Norberto Bensa <nbensa@gmail.com> wrote:

> Quoting Josh Cepek <josh.cepek@usa.net>:
>
>  Personally I'd suggest using LVM for this
>>
>
>
-- 
Alan Davis

"It's never a matter of liking or disliking ..."
---Santa Ynez Chumash Medicine Man

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Re: [gentoo-user] Advice about setting up split home directory

[Walter Dnes]

On Mon, Aug 04, 2008 at 03:10:37PM +1000, Alan E. Davis wrote
> Norberto and  Josh:
> 
> Thank you for the suggestion.  It's on the back burner.  I have the space to
> experiment with it now.  I have balked for the time being on basis of,
> partly, my need to be able to swap drives in and out, and have it clear in
> mind which partitions belong to what.  Also my main drive is a 10000 RPM
> faster drive, and I'd like to keep the partitions or directories that are
> mainly for storage separated.  I really do notice a difference in the
> performance of the drive.  this is somewhat of a conundrum: how to keep the
> current projects focused on the faster drive.

  There's another approach with bind mounts to reduce wasted space.  The
following example is not a joke (notwithstanding the opinions of some
posters here <g>).  I used a 500 megabyte / partition, playing it safe
because it was my first try, but I could've gotten away with 200 megs.
Here's what "fdisk -l" and "df" show...

[d530][root][~] fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xd0000000

   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

[d530][root][~] df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda5               482186     30376    426913   7% /
udev                     10240       152     10088   2% /dev
/dev/sda7            483959368 100296316 383663052  21% /home
shm                    1031872         0   1031872   0% /dev/shm


  I create empty /opt /tmp /usr and /var directories in the 500 meg main
partition (sda5).  Except for swap, the rest of the drive is allocated
to sda7, which is mounted as /home.  I create /home/bindmounts and then
/home/bindmounts/opt /home/bindmounts/tmp /home/bindmounts/usr and
/home/bindmounts/var.  Then I bindmount them to their equivalants on the
/ partition.  I have a script to set up the correct permissions.  The
result is that you can run with a 200 meg main partition, without using
LVM.  Under /home is /home/misc, where I put /home/misc/movies/
/home/misc/music and /home/misc/photos.

  This may not be ideal for a production server, but I like it at home,
because I don't have to screw around with multiple partitions.

-- 
Walter Dnes <waltdnes@waltdnes.org>

Re: [gentoo-user] LVM Migration Example (was: Advice about setting up split home directory)

[Josh Cepek]

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Norberto Bensa wrote:
> Quoting Josh Cepek <josh.cepek@usa.net>:
>> 3) You can easily migrate between hard drives while the system is
>> online by moving LV's from one Physical Volume (PV) (eg: a hard disk)
>> to another.
> 
> --!!
> 
> Have you ever tried that? I've almost killed both hard drives doing an 
> on-line migration to a bigger HD. I wouldn't recommend it.

Actually, yes, and with fairly decent results.  You are right that his 
process will take quite a while on large LV's, and doing other 
disk-intensive operations at the same time will bring the system to a 
crawl.  However, I used this technique to remove an old NTFS partition 
when I migrated to a VM for my Windows system.

To recover the space into a single larger PV (a single PV was important 
for me here) I attached an external USB 2.0 drive, created a PV, and 
added it to my pre-existing VG.  I then pvmove-ed the data over to the 
external drive, removed the old partitions, and re-created a single 
larger partition on the internal drive.  Once the LV's were migrated 
back I removed the PV on the external drive.

In my case I also moved my non-LVM root partition to the end of the 
drive after the migration to the external drive, but had I not needed to 
do this I could have performed the entire operation without needing to 
even reboot.

All in all I think this example demonstrates the utter flexibility you 
get with LVM.  I leave it up to each user to determine where flexibility 
ends and insanity takes over ;)


-- 
Josh


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Re: [gentoo-user] Advice about setting up split home directory

[Drew Tomlinson]

Alan E. Davis wrote:
> Norberto and  Josh:
>
> Thank you for the suggestion.  It's on the back burner.  I have the 
> space to experiment with it now.  I have balked for the time being on 
> basis of, partly, my need to be able to swap drives in and out, and 
> have it clear in mind which partitions belong to what.  Also my main 
> drive is a 10000 RPM faster drive, and I'd like to keep the partitions 
> or directories that are mainly for storage separated.  I really do 
> notice a difference in the performance of the drive.  this is somewhat 
> of a conundrum: how to keep the current projects focused on the faster 
> drive.  
>
> Interestingly (to me) while I carefully planned for swap on the faster 
> drive, since I moved to 2GB of RAM, I think I've only touched swap two 
> or three times, and then only passingly! 
>
> I definitely wouldn't want to put / into LVM. 
>
> If I do LVM it will be the easy way, the most clearcut way.

As one that's used LVM and other similar software in both Windows and 
the BSDs, be sure you understand the risk involved.  While the idea of 
"one big drive" sounds appealing (which is why I used it), lose one 
drive and you lose everything in the LV unless you are mirroring, using 
parity, or some combination of both.  I have been bit by this time and 
time again and have finally decided that LVM is not worth the hassle for 
me any longer, especially since a 1 TB drive can be found easily for 
less than $200 (US).

Anyway, I'm not knocking those who use LVM.  Just understand the risk.  :)

Cheers,

Drew

-- 
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