> On Fri, 13 Nov 2009, inouk wrote:
> Your system has every little RAM (512MB). It is less
> than is
> recommended for Solaris 10 or for zfs and if it was a
> PC, it would be
> barely enough to run Windows XP. Since zfs likes to
> use RAM and
> expects and sufficient RAM will be available, it
> seems likely that
> this system is both paging badly, and is also not
> succeeding to cache
> enough data to operate efficiently. Zfs is
> re-reading from disk where
> normally the data would be cached.
>
> The simple solution is to install a lot more RAM.
> 2GB is a good
> tarting point.
>
I don't agree, especially if you compare with Windows XP. It has windowing
system and any other fancy stuffs. The server I'm talking about has nothing on
it except system background processes (sendmail, kernel threads, and all).
Finally, swap isn't used at all. So, I could say almost 90% of ram is
available for zfs operations.
Anyway, I discovered something interesting: while investigating, I "offlined"
the second disk in mirror pool:
============================================================
pool: rpool
state: DEGRADED
status: One or more devices has been taken offline by the administrator.
Sufficient replicas exist for the pool to continue functioning in a
degraded state.
action: Online the device using 'zpool online' or replace the device with
'zpool replace'.
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
rpool DEGRADED 0 0 0
mirror DEGRADED 0 0 0
c0t0d0s0 ONLINE 0 0 0
c0t2d0s0 OFFLINE 0 0 0
errors: No known data errors
============================================================
It went from 650KB to 1200KB (1.2MB) according to pfilestat:
============================================================
STATE FDNUM Time Filename
running 0 5%
waitcpu 0 12%
read 0 16% /opt/export/flash_recovery/OVO_2008-02-20.fl
sleep-r 0 65%
STATE FDNUM KB/s Filename
read 0 1200 /opt/export/flash_recovery/OVO_2008-02-20.fl
Total event time (ms): 4999 Total Mbytes/sec: 1
============================================================
Also, in read transferts, sevice time reduced to between 80ms and 100ms:
============================================================
device r/s w/s kr/s kw/s wait actv svc_t %w %b
dad0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
dad1 168.8 0.0 21608.9 0.0 13.5 1.7 89.9 78 88
============================================================
Sounds like a bus bottleneck, as if two HD's can't use the same bus for data
transfert. I don't know the hardware specifications of Netra X1, though...
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