On Mon, 14 Mar 2005, Eric Sandeen wrote:
> Robin Humble wrote:
>
> > Some ways forward:
> > - convince RedHat to put 8k stacks (or at least the option for it) and
> > XFS into AS4.
>
> FWIW, I try to steer the conversation away from "xfs is broken with 4k
> stacks" and towards "4k stacks don't work for some applications." :)
>
> XFS can chew through stack a bit faster than some of the filesystems, to
> be sure. But I've always meant to try to put together some diabolical
> "supported" config on RHEL4 and file a bug - say nfs over deeply nested
> volume managers, or something like that.
>
> > - try to make XFS play nicer with 4k stacks
> > - run fc3. fc3 and AS4 are very similar (~ 50% of userland rpms are
> > identical, the rest seem to be fairly minor variations), so if your
> > vendor supports AS4 then it'll almost certainly run fine on fc3
>
> but both fc3 and RHEL4 have 4k stacksm though...
>
> > - install AS4 but run a fc3 (recompiled for 8k stacks) kernel
>
> ...ah, yes.
>
> > - install AS4 but run a stock kernel.org (or XFS cvs) kernel
>
> Seems like with RHEL3, stock kernel.org kernels don't play nicely. I
> hope this isn't the case with RHEL4, but I have not tested it.
That's not the case across the board. I'm running a stock kernel.org 2.6
kernel on RHEL3 (for almost a year now) and haven't had any problems.
Perhaps i've not hit whatever issue you've experienced?
> > The first 2 of these are hard, the last 2 are pretty easy but may not
> > help you from a vendor support point of view. We'll probably choose the
> > last option.
> > The middle option (fc3) is what you are doing now, so you can get some
> > idea of XFS stability with 4k stacks for your particular workload.
> >
> > I wonder why RedHat was so keen to remove 8k as an option. Things would
> > be fairly simple if they hadn't done that.
>
> I think there are some applications (java?) that can benefit from
> smaller stacks in terms of overal thread count & memory usage... but I
> don't know why they went so far as to actually remove the option.
Could be. The RHEL3 boxes where i'm running a 2.6.x kernel are also
running JBoss.
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Lonni J Friedman netllama@xxxxxxxxxxxxx
LlamaLand http://netllama.linux-sxs.org
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