Hi All,
the separating of /var is something that comes from the Unix
tradition. Much of the Unix tradition of systems administration is
based on making sure systems with many users remain stable and so
administrators are prepared to work to make the system more reliable.
Common Windows, Linux and OS X practices are dominated by the concept
of a personal computer ie you only hurt yourself so ease is a priority
to them.
The original filesystem layout separated
/
/var
/tmp
/usr
onto separate filessytems. In the bad old days every time there is a
write there is risk that the filesystem may be made unstable so the
aim was to minimise writes to / as without / booting to a minimal
environment is a serious trial.
/tmp was used for data that is not required to persist over reboots.
/var was used for data that should persist over reboots
The other filesystems were used to store user files / non-minimal boot
programs etc
By separating the filesystems it is possible to make a far more
recoverable system in the event of:
- a user deciding to fill up all of one piece of temporary storage
(ramdisk /tmp was one of those optimisations that sun made that had
some serious negative consequences; many admins on large shared
systems make it back into a disk backed filesystem)
- high write rate to other filesystems reduces risk of boot affecting
writes from being made
So keeping /var and /tmp separate make life much easier. Some of us
have even been known to run with a read-only root filesystem.
Linux and windows users appear to value the flexibility of not having
to make system use decisions ie how big /var and /tmp should be at
installation and being able to use the disk as they see fit; however,
they are typically not managing systems for others and so they have
made a choice of convenience which can be seriously inconvenient in a
shared environment.
Maurice Castro
On 24/06/2008, at 10:45 AM, Richard Elling wrote:
>
> I think the ability to have different policies for file systems
> is pure goodness -- though you pay for it on the backup/
> restore side.
>
> A side question though, my friends who run Windows,
> Linux, or OSX don't seem to have this bias towards isolating
> /var. Is this a purely Solaris phenomenon? If so, how do we
> fix it?
> -- richard
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