[SLUG] Re: Partitions

[john at johnallsopp.co.uk]

> On Thu, 2006-03-23 at 17:10 +0000, Stephen O'Neill wrote:
>
>> FWIW I only have /home on a separate partition to /.
>>
>> Steve O
>
> Yeah, that makes sense. Especially if you switch distro's at some
> point,
> or want to share it between a few. I usually do that too but I went
> for
> the default Ubuntu settings this time and it gave me one big /.
>
> I'm not too worried about it. I might be when it all fsck's up though
> and I loose my user settings ;)

The reasoning goes like this:

Any corruption stays in the partition, fsck takes less time to check
and repair it and it's easier to isolate.

You can vary the block sizes of each partition depending on usage, so
increasing the efficiency of disc space use.

You can limit data growth. Linix will crash if it runs out of disc
space, so if the data is separate from the OS it won't crash. Things
that might overrun your disc are: runaway processes, user behaviours
and anywhere you allow people to download stuff.

It makes backups easier.


Whereas I'd say some of those things are 'old' in that disc space is
now cheap, the LPI advice is that you should cut down/amalgamate
partitions where disc space is limited. In other words, use more
partitions if you have plenty of disc space.


The LPI thing also discusses the idea of collecting files together by
how often they are updated. For instance, /bin, /sbin, /usr/bin, etc
have a long lifetime. By collecting them together you don't have to
back them up so often.

/var is relatively short lived. Maybe that needs daily backup.

/var/spool/lpd files live for a few minutes only.


Ideally, what's recommended is:

A small root filesystem. Small so it's less likely to be corrupted. On
a small disc it would include quite a lot so 850MB, but on a large
disc lots is out in other partitions so 100MB. FC4 required 250MB at
least. I ended up with 500MB.

/var, this contains spool directories for mail and printing and error
logs. If a server develops a chronic error you don't want the error
logs overrunning the system. Maybe 500MB or 1GB. I read "make it big
enough to handle logs and their rotation schemes (but not so large as
to waste space)", but I don't understand what that means. I ended up
with 1GB.

/usr, contains most executable binaries, the kernel source tree, much
documentation. If you make this a separate partition you can share it,
read-only, among other systems via NFS so reducing updating headaches.
It recommends making it big enough to accommodate kernel building, so
1GB if system is large. I ended up with 5GB.

/tmp contains temporary files for some programs which are usually
small but it depends on the app. Should be large enough to accommodate
all usage from all users. 100MB? 500MB? I ended up with 500MB.

/home. This will be heavily used. If you don't impose quotas, this
ought to be in its own partition or the users will fill the disc. Be
generous tho. Maybe 100GB if plenty of disc space. I ended up with
8.5GB so I could back it up to DVD.

/boot, contains kernel images, make it small 50MB (FC4 wants 75MB),
and placed below cylinder 1024. I ended up with 100MB.


There y'go. Just reporting what I've been taught, since I keep seeing
blank faces on this subject.

Some of the stuff, in retrospect, applies to multiuser systems so
perhaps I shouldn't have taken them so fully to heart but there you
go.

Cheers
J