[OmniOS-discuss] [discuss] crash dump speed painfully slow

[Schweiss, Chip]

On Wed, Nov 5, 2014 at 2:36 PM, Dan McDonald <danmcd at omniti.com> wrote:

>
> > On Nov 5, 2014, at 3:31 PM, Schweiss, Chip via illumos-discuss <
> discuss at lists.illumos.org> wrote:
> >
> > I had a system crash this morning when I/O on a pool was hung with
> failmode=panic.
>
> What version of OmniOS are you running?
>

r1510010


>
> > That was 7 1/2 hours ago and it's at 64%.    I'm going to let it
> complete so the failure can be analyzed more, but I really need to find a
> way to significantly speed up the crash dumps.
> >
> > This system has 256GB ram and a dedicated dump pool of two 320GB
> mirrored SATA disks.
> >
> > I'm aware of the multi-threaded dump issue so I have these to lines in
> /etc/system
> >
> > set dump_plat_mincpu=0
>
> That should be the default now.  I can't remember which rev of OmniOS it
> showed up in, but certainly it's in 010 or later.
>
> > It's not clear where the bottleneck is.  I don't think it's the disk.
> The disk activity lights are a light flicker, by no means being hit hard.
> Unless it's a serial latency issue.
> >
> > What would be my best approach to get good dumps from a system like this
> in minutes, not hours?   Assuming that is possible.
>
> You weren't dumping to the same pool or the same controller where you had
> the I/O hang, were you?
>

No, I setup a dedicated dump pool to a pair of mirrored SATA disks
connected to the motherboard AHCI controller.

-Chip

>
> Dan
>
>
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