Subject: Maximum partition size relative to system memory?
To: None <tech-userlevel@netbsd.org>
From: John Klos <john@sixgirls.org>
List: tech-userlevel
Date: 07/11/2003 22:21:57
Hi,

I have an Amiga 4000 server which has 128 megs of memory. Soon I will be
replacing one of the disks and plan to set up a singe 250 gig partition on
the new drive. My question / request for comment is this: is it possible
that 128 megs of memory is not enough for fsck to run against a 250 gig
partition?

Running fsck on a 65 gig partition gives me this:

  PID USERNAME PRI NICE   SIZE   RES STATE      TIME   WCPU    CPU COMMAND
25168 root      64    0    73M   39M RUN        2:15 16.70% 16.70% fsck_ffs

Note that I ran this while the system was multiuser, so plenty of swap was
available.

So - assuming that I might not have enough memory, what can be done? Is
anyone familiar enough with the fsck code to know whether it will run out
of memory and die, or use a less memory intensive algorithm, or what?

Personally, I'd like to see a mechanism whereby a partition can be marked
in fstab to be non-critical for going multiuser, so a system can boot
multiuser and start an fsck in the background with swap available. This is
basically what I plan to do (ie, have it set to noauto and run fsck in the
background via rc.local), but maybe it should be an option in the startup
scripts.

Thoughts?

John Klos
Sixgirls Computing Labs