2GB memory limit running fsck on a +6TB device

[Andreas Dilger]

On Jun 09, 2008  18:37 -0400, Theodore Ts'o wrote:
> On Mon, Jun 09, 2008 at 03:50:32PM -0600, Andreas Dilger wrote:
> > I don't know offhand how important the dblist structure is, so I'm not
> > sure if there is a way to reduce the memory usage for it.  I believe
> > that in low-memory situations it is possible to use tdb in newer versions
> > of e2fsck for the dblist, but I don't know much of the details.
> 
> Yep, please see [scratch_files] section in e2fsck.conf.  It is
> described in the e2fsck.conf(5) man page.

Hmm, maybe if the ext2fs_init_dblist() function returns PR_1_ALLOCATE_DBCOUNT
this should be a user-fixable problem that asks if the user wants to use
an on-disk tdb file in /var/tmp, and if that is a "no" then point them at
the right section in /etc/e2fsck.conf?

I don't think it is reasonable to default to using /tmp, because it might
be a RAM-backed filesystem, and I suspect in most cases the root filesystem
will not run out of memory in this way...  Even if it fails because /var/tmp
is read-only, or too small, it is no worse off than it is today.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.