[OpenIndiana-discuss] ZFS pool slow as molasses

[Brett Dikeman]

On Tue, Oct 5, 2010 at 4:01 PM, Julian Wiesener <jw at vtoc.de> wrote:
> Hi,
>
> as far as i see (device names in iostat) you're using the PATA interface to
> the SATA drives. Please look if you have an "native AHCI" switch in the BIOS
> and turn it on, the SATA drivers are way better implementet.

Alright, fair enough- I rebooted the server and checked the BIOS.  IDE
controller #1 was set to "IDE", not AHCI.

Flipped it over to AHCI, and the machine wouldn't boot.  The progress
bar comes up and fills twice (blue and orange), then the screen goes
blank and I'm back at the POST screen.

I put it back to "IDE", and the machine booted OK.  I'm seeing pretty
good performance from our disk backup software, but if I stop it, the
scrub (which picked up where it left off) is still running at a crawl.

I'm happy to switch to AHCI, so suggestions on getting the system to
boot with that are welcome (does a device name need to be changed
somewhere?  I don't see anything obvious in /rpool/boot/grub/menu.lst,
for example.)  In the meantime, I'm regularly seeing iostat figures
bounce between 10 and 200MB on the data pool with our backup software
running, so....not sure why the scrub isn't capable of running at the
same rate.  If I shut down the backup software, I see figures like
this:

----------  -----  -----  -----  -----  -----  -----
data   5.55T  1.70T     69      0   163K      0
rpool       18.9G  10.6G      0      0      0      0
----------  -----  -----  -----  -----  -----  -----

Brett