zpool - low speed write

[Jeremy Chadwick]

On Wed, Aug 04, 2010 at 08:08:24PM +0800, Alex V. Petrov wrote:
> ada2 at ahcich2 bus 0 scbus2 target 0 lun 0
> ada2: <WDC WD10EADS-00M2B0 01.00A01> ATA-8 SATA 2.x device
> ada2: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
> ada2: Command Queueing enabled
> ada2: 953869MB (1953525168 512 byte sectors: 16H 63S/T 16383C)
> ada3 at ahcich3 bus 0 scbus3 target 0 lun 0
> ada3: <WDC WD10EADS-00L5B1 01.01A01> ATA-8 SATA 2.x device
> ada3: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
> ada3: Command Queueing enabled
> ada3: 953869MB (1953525168 512 byte sectors: 16H 63S/T 16383C)
> ada4 at ahcich4 bus 0 scbus4 target 0 lun 0
> ada4: <WDC WD10EADS-00M2B0 01.00A01> ATA-8 SATA 2.x device
> ada4: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
> ada4: Command Queueing enabled

Your ada3 disk is different from the other two.  Can you please provide
the output from the following 3 commands?

camcontrol identify ada2
camcontrol identify ada3
camcontrol identify ada4

> vfs.zfs.cache_flush_disable=1
> vfs.zfs.zil_disable=1

I question both of these settings, especially the latter.  Please remove
them both and re-test your write performance.

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |