MUCH faster

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MUCH faster

Postby haer22 » Tue May 20, 2014 10:49 pm

My scrub just completed. And it is so very much faster than before.

Code: Select all
  scan: scrub in progress since Tue May 20 21:45:59 2014
    6,03T scanned out of 6,12T at 164M/s, 0h9m to go
    0 repaired, 98,59% done
config:
   NAME         STATE     READ WRITE CKSUM
   zeus         ONLINE       0     0     0
     raidz2-0   ONLINE       0     0     0
       disk4s2  ONLINE       0     0     0
       disk5s2  ONLINE       0     0     0
       disk6s2  ONLINE       0     0     0
       disk7s2  ONLINE       0     0     0
   logs
     disk2s4    ONLINE       0     0     0
   cache
     disk2s5    ONLINE       0     0     0

Previously, the speed would have been 10-20MB/s and it would have taken 50-60hrs to complete. During that time the system would be sluggish.

In 3 days my other pool will start its bi-weekly scrubbing. I'll be back with some figures.
haer22
 
Posts: 123
Joined: Sun Mar 23, 2014 2:13 am

Re: MUCH faster

Postby haer22 » Wed May 21, 2014 4:57 am

As a happy camper I started the scrub on my other pool, a mirrored 2*4TB.

BUT, it was not only very slow it was almost hibernating :-) at 600-700kB/s (kiloByte!). My old trick of export/re-import did not make any difference. OK, maybe som buffers or whatever so I rebooted the box. Still slooooow. And it skipped scrubbing and started resilvering:
Code: Select all
  pool: hera
 state: ONLINE
status: One or more devices is currently being resilvered.  The pool will
   continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
  scan: resilver in progress since Wed May 21 14:28:14 2014
    1024M scanned out of 3,37T at 803K/s, (scan is slow, no estimated time)
    940M resilvered, 0,03% done
config:

   NAME         STATE     READ WRITE CKSUM
   hera         ONLINE       0     0     0
     mirror-0   ONLINE       0     0     0
       disk1s2  ONLINE       0     0     0
       disk4s2  ONLINE       0     0     1  (resilvering)
   logs
     disk3s2    ONLINE       0     0     0
   cache
     disk3s3    ONLINE       0     0     0

errors: No known data errors

1. Why so slow? The number of IOPS is around 70. So even if it was all 1 byte files, the IOPS should be way higher, yes? And even with the old version, the speed was never under 10MB/s.
2. If it found a checksum error, why resilver the whole disk?

Nothing suspicious in tail -10000f /var/system/log | grep -E '(zfs)|(disk)' what I can see.
haer22
 
Posts: 123
Joined: Sun Mar 23, 2014 2:13 am


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