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

[Dan McDonald]

> 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?

> 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?

Dan