zpool - low speed write

[Alex V. Petrov]

В сообщении от 5 августа 2010 14:19:59 вы написали:

> 
> Can you please remove use of the zpool entirely (e.g. zpool destroy
> tank) and do a write test to each disk itself?  E.g.:
> 
> dd if=/dev/zero of=/dev/ad8 bs=64k count=1000000
> dd if=/dev/zero of=/dev/ad10 bs=64k count=1000000
> dd if=/dev/zero of=/dev/ad12 bs=64k count=1000000
> 
> I don't recommend using large block sizes (e.g. bs=1M, bs=3M).

dd if=/dev/zero of=/dev/ad8 bs=64k count=1000000
1000000+0 records in
1000000+0 records out
65536000000 bytes transferred in 604.849406 secs (108350937 bytes/sec)

dd if=/dev/zero of=/dev/ad10 bs=64k count=1000000
1000000+0 records in                                                  
1000000+0 records out
65536000000 bytes transferred in 757.755459 secs (86487005 bytes/sec)

dd if=/dev/zero of=/dev/ad12 bs=64k count=1000000
1000000+0 records in
1000000+0 records out
65536000000 bytes transferred in 604.857282 secs (108349526 bytes/sec)
 
> If all of the above dds show good/decent throughput, then there's
> something strange going on with ZFS.  If this is the case, I would
> recommend filing a PR and posting to freebsd-fs about the problem,
> pointing folks to this thread.
> 
> If all of the dds show bad throughput, then could you please do the
> following:
> 
> - Provide vmstat -i output
> - Install ports/sysutils/smartmontools and run smartctl -a /dev/ad8,
>   smartctl -a /dev/ad10, and smartctl -a /dev/ad12
> 
> If only one of the dds shows bad throughput, then please:
> 
> - Install ports/sysutils/smartmontools and run smartctl -a /dev/XXX,
>   where XXX is the disk which has bad throughput
> - Try making a ZFS pool with all 3 disks, but then do "zpool offline
>   tank XXX" and then re-attempt the following dd:
>   dd if=/dev/zero of=/tank/test.zero bs=64k count=1000000
>   And see what throughput looks like.
> 
> Thanks.

-----
Alex V. Petrov