Hi, On Thu, Mar 20, 2003 at 01:27:19AM -0500, Theodore Ts'o wrote: > On Thu, Mar 20, 2003 at 02:38:38PM +0900, Miles Bader wrote: > > Really only /etc needs to be available on the root filesystem; /run > > (or /var/my-persistant-cache, or whatever it's called) doesn't -- it > > can be mounted very early if necessary for special situations. > > /etc/blkid.tab may be necessary to find the /var partition. (i.e., if > /etc/fstab has LABEL=var, and you don't want to search all of the 2000 > block devices in the system, then you want to use /etc/blkid.tab to be > able to quickly find the var partition.) > > Similarly, /etc/ld.so.cache is necessary to run the mount command (and > any other dynamically linked executable). So saying that they can > live on another partition is simply not correct, and seems to indicate > that the person making the argument doesn't understand the issues > involved. > > If "/run can be mounted very early", then there's no point to have a > separate /run directory to clutter up the root partition. /var can > simply be mounted early. The whole point of /run is because it needs > to be on the root. The question then is that if /run must be on the > root, and /etc must be on the root, why bother separating the two? > > The reason why it's in /etc/blkid.tab and not /var/run/blkid.tab is > *precisely* because it must be on the root partition. /var might not > be on the root partition. The thing with these caches is that if you live on a fairly static system, they may still be on fs that's always R/O except for maintenance tasks such as installing software or changing disks. I think /etc is not a problem for /etc/ld.so.cache or /etc/blkid.tab, but it /is/ a problem for information that changes during the boot process (for which /run would be a better candidate) or at run time (/var/run if not persistent, /var/lib if it is). So as long as you don't also use /etc/blkid.tab to keep state such as mount counters or timestamps, but separate that so it can be put in /var/run or /var/lib and the tools can work with a missing statefile before /var is mounted, it seems fine to use /etc. Cheers, Emile. -- E-Advies - Emile van Bergen emile@e-advies.nl tel. +31 (0)70 3906153 http://www.e-advies.nl
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