Robin Humble wrote:
Under what conditions should we be worried about XFS with a kernel
compiled with 4k stacks?
As we are lazy, we would prefer to run a stock fc3 kernel on dual Xeon
32bit with 3ware hardware SATA RAID - mostly accessed via NFS. No LVM,
no ACLs, no software RAID, so nothing too fancy.
Is this still asking for trouble?
There are still a few large stack users in xfs even when it's used by
itself - one that comes to mind is code that runs when you use xfs_fsr
(hm, I really must check in my fix for that....) And figuring out
callchain depth is tricky, so hard to say how these things will all add up.
I guess I would suggest that you just test it out on one non-critical
box, with a "normal" workload for you, and see how it fares. It's
tight, but in many cases it might be just fine.
If so, then it's not hard to recompile the fc3 kernel (or a stock
kernel) for 8k stacks, just we're not too sure how risky the default
fc3 setup is.
You'll know after you figure out how often you hit problems. :)
We're also thinking of running RHEL AS4 instead of fc3 (they are very
similar), but that definitely needs a recompile as XFS isn't included in
the default AS4 kernel :-/
Yep... that's something I've been meaning to look into as well -
although the 4k stack issue remains.