Date: Mon, 22 Oct 2012 07:34:49 +0200 From: Henti Smith <henti@geekware.co.za> To: freebsd-questions@freebsd.org Subject: Strange I/O problem on Freenas 0.7.2 Message-ID: <CAC_HdUr%2Btz2fAnFZ8uBTLTQ8O3A5CRxxn-b_NbbS3-3jv_d0OQ@mail.gmail.com>
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Hi all.
I'm having a very weird problem with a friends Freenas set-up. I'm
trying to backup his data before migrating to nas4free or just plain
FreeBSD.
The setup is as follows:
HP Microserver N36.
2BG Mem (1713 MB Usable) (no swap)
4 x 2000GB (ST2000DL003-9VT166 Seagate) drives in a graid5 setup.
Initially he had no problems with the setup. Samba share was fine and
he populated the raid set with 3TB of data, but somewhere along the
line the disk I/O went VERY slow.
I initially thought this might be raid related and did some tests but
actually found the problem to be on the discs.
[root@freenas ~]# diskinfo -c /dev/ad4
/dev/ad4
512 # sectorsize
2000398934016 # mediasize in bytes (1.8T)
3907029168 # mediasize in sectors
3876021 # Cylinders according to firmware.
16 # Heads according to firmware.
63 # Sectors according to firmware.
ad:5YD2VEWQ # Disk ident.
I/O command overhead:
time to read 10MB block 0.250736 sec = 0.012 msec/sector
time to read 20480 sectors 79.653738 sec = 3.889 msec/sector
calculated command overhead = 3.877 msec/sector
[root@freenas ~]# diskinfo -t /dev/ad4
/dev/ad4
512 # sectorsize
2000398934016 # mediasize in bytes (1.8T)
3907029168 # mediasize in sectors
3876021 # Cylinders according to firmware.
16 # Heads according to firmware.
63 # Sectors according to firmware.
ad:5YD2VEWQ # Disk ident.
Seek times:
Full stroke: 250 iter in 124.649884 sec = 498.600 msec
Half stroke: 250 iter in 52.112172 sec = 208.449 msec
Quarter stroke: 500 iter in 167.991252 sec = 335.983 msec
Short forward: 400 iter in 72.027133 sec = 180.068 msec
Short backward: 400 iter in 150.708625 sec = 376.772 msec
Seq outer: 2048 iter in 5.748059 sec = 2.807 msec
Seq inner: 2048 iter in 119.395823 sec = 58.299 msec
Transfer rates:
outside: 102400 kbytes in 39.207296 sec = 2612 kbytes/sec
middle: 102400 kbytes in 113.757181 sec = 900 kbytes/sec
inside: 102400 kbytes in 153.438159 sec = 667 kbytes/sec
S.M.A.R.T. is not reporting any issues either and the speeds are
similar on all the drives. No errors in /var/log either.
Any help or suggestions would be appreciated.
Regards
Henti
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