Am Thu, 23 Mar 2017 15:38:05 +0300 Slawa Olhovchenkov <s...@zxy.spb.ru> schrieb:
> On Wed, Mar 22, 2017 at 10:25:24PM +0100, O. Hartmann wrote: > > > Am Wed, 22 Mar 2017 21:10:51 +0100 > > Michael Gmelin <free...@grem.de> schrieb: > > > > > > On 22 Mar 2017, at 21:02, O. Hartmann <ohartm...@walstatt.org> wrote: > > > > > > > > CURRENT (FreeBSD 12.0-CURRENT #82 r315720: Wed Mar 22 18:49:28 CET 2017 > > > > amd64) is > > > > annoyingly slow! While scrubbing is working on my 12 GB ZFS volume, > > > > updating /usr/ports takes >25 min(!). That is an absolute record now. > > > > > > > > I do an almost daily update of world and ports tree and have periodic > > > > scrubbing > > > > ZFS volumes every 35 days, as it is defined in /etc/defaults. Prts tree > > > > hasn't > > > > grown much, the content of the ZFS volume hasn't changed much (~ 100 > > > > GB, its fill > > > > is about 4 TB now) and this is now for ~ 2 years constant. > > > > > > > > I've experienced before that while scrubbing the ZFS volume, some > > > > operations, > > > > even the update of /usr/ports which resides on that ZFS RAIDZ volume, > > > > takes a bit > > > > longer than usual - but never that long like now! > > > > > > > > Another box is quite unusable while it is scrubbing and it has been > > > > usable times > > > > before. The change is dramatic ... > > > > > > > > > > What do "zpool list", "gstat" and "zpool status" show? > > > > > > > > > > > zpool list: > > > > NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH > > ALTROOT > > TANK00 10.9T 5.45T 5.42T - 7% 50% 1.58x ONLINE - > > > > Deduplication is off right now, I had one ZFS filesystem with dedup enabled > > > > gstat: not shown here, but the drives comprise the volume (4x 3 TB) show > > 100% busy > > each, but one drive is always a bit off (by 10% lower) and this drive is > > walking > > through all four drives ada2, ada3, ada4 and ada5. Nothing unusual in that > > situation. > > But the throughput is incredible low, for example ada4: > > > > L(q) ops/s r/s kBps ms/r w/s kBps ms/w %busy Name > > 2 174 174 1307 11.4 0 0 0.0 99.4| ada4 > > > > kBps (kilo Bits per second I presume) are peaking at ~ 4800 - 5000. On > > another bos, > > this is ~ 20x higher! Most time, kBps r and w stay at ~ 500 -600. > > kilo Bytes. > 174 rps is normal for general 7200 RPM disk. Transfer too low by every > request is about 1307/174 = ~8 KB. Don't know root cause of this. I am > see raid-z of 4 disk, 8*3 = ~24KB per record. May be compession enable > and zfs use 128KB record size? For this case this is expected > performance. Use 1MB and higher record size. > I've shutdown the box over night and rebooted this morning. After checking from remote the output of "zpool status", the throughput was at ~229 MBytes/s - a value I'd expected, peaking again at ~ 300 MBytes/s. I assume my crap home hardware is not providing more, but at this point, everything is as expected. The load, as observed via top, showed ~75 - 85% idle (top -S). But anyway, on the other home box with ZFS scrubbing active, the drives showed a throughput of ~ 110 MBystes/s and 129 MBytes/s - also value I'd expected. But the system was really jumpy and the load showed ~ 80% idle (two cores, 4 threads, 8 GB RAM, the first box mentioned with the larger array has 4 cores/8 threads and 16 GB). -- O. Hartmann Ich widerspreche der Nutzung oder Übermittlung meiner Daten für Werbezwecke oder für die Markt- oder Meinungsforschung (§ 28 Abs. 4 BDSG).
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