slow RAID-5 on FreeBSD 5.4

[Ted Mittelstaedt]

Try regenerating the array and put it in striped mode, rather than raid-5
redundant mode, and see what happens.  You might also try setting it
up as a mirror raid-0/1 and test.  I'm sure everyone here would be
interested
in the results, I know I would.

Ted

>-----Original Message-----
>From: owner-freebsd-questions at freebsd.org
>[mailto:owner-freebsd-questions at freebsd.org]On Behalf Of Tamouh H.
>Sent: Saturday, January 21, 2006 4:15 PM
>To: freebsd-questions at freebsd.org
>Subject: RE: slow RAID-5 on FreeBSD 5.4
>
>
>
>On another note, I've ran diskinfo test and these are the
>results, much better but still the RAID-5 slower than a single drive:
>
>impala# diskinfo -t aacd1
>aacd1
>        512             # sectorsize
>        146781044736    # mediasize in bytes (137G)
>        286681728       # mediasize in sectors
>        17845           # Cylinders according to firmware.
>        255             # Heads according to firmware.
>        63              # Sectors according to firmware.
>
>Seek times:
>        Full stroke:      250 iter in   3.291258 sec =   13.165 msec
>        Half stroke:      250 iter in   2.362839 sec =    9.451 msec
>        Quarter stroke:   500 iter in   3.908358 sec =    7.817 msec
>        Short forward:    400 iter in   2.478195 sec =    6.195 msec
>        Short backward:   400 iter in   2.459182 sec =    6.148 msec
>        Seq outer:       2048 iter in   0.661217 sec =    0.323 msec
>        Seq inner:       2048 iter in   0.637923 sec =    0.311 msec
>Transfer rates:
>        outside:       102400 kbytes in   1.659174 sec =
>61717 kbytes/sec
>        middle:        102400 kbytes in   1.763043 sec =
>58081 kbytes/sec
>        inside:        102400 kbytes in   2.867523 sec =
>35710 kbytes/sec
>
>impala# diskinfo -t aacd0
>aacd0
>        512             # sectorsize
>        293561434112    # mediasize in bytes (273G)
>        573362176       # mediasize in sectors
>        35690           # Cylinders according to firmware.
>        255             # Heads according to firmware.
>        63              # Sectors according to firmware.
>
>Seek times:
>        Full stroke:      250 iter in   2.966840 sec =   11.867 msec
>        Half stroke:      250 iter in   2.270758 sec =    9.083 msec
>        Quarter stroke:   500 iter in   4.493850 sec =    8.988 msec
>        Short forward:    400 iter in   2.681128 sec =    6.703 msec
>        Short backward:   400 iter in   1.520458 sec =    3.801 msec
>        Seq outer:       2048 iter in   0.631963 sec =    0.309 msec
>        Seq inner:       2048 iter in   0.625584 sec =    0.305 msec
>Transfer rates:
>        outside:       102400 kbytes in   2.139737 sec =
>47856 kbytes/sec
>        middle:        102400 kbytes in   3.080063 sec =
>33246 kbytes/sec
>        inside:        102400 kbytes in   4.358889 sec =
>23492 kbytes/sec
>
>>
>> Hello,
>>
>> I've just ran Bonnie on a FreeBSD 5.4 machine with Adaptec
>> 2230SLP RAID-5 SCSI Card and Seagate 146GB 10K RPM U320 drives.
>>
>> The results were very surprising. The RAID-5 is EXTREMELY
>> slow, and I can't figure out why!
>>
>> The RAID controller has two volumes: RAID-5 and a lone drive.
>>
>> This is Bonnie results from the lone drive on the Adaptec card:
>>
>> impala# ./Bonnie -d /tmp
>> File '/tmp/Bonnie.30883', size: 104857600 Writing with
>> putc()...done Rewriting...done Writing intelligently...done
>> Reading with getc()...done Reading intelligently...done
>> Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done...
>>               -------Sequential Output-------- ---Sequential
>> Input-- --Random--
>>               -Per Char- --Block--- -Rewrite-- -Per Char-
>> --Block--- --Seeks---
>> Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
>> K/sec %CPU  /sec %CPU
>>           100 27168 28.2 31668 13.9 36530 10.8 83540 92.1
>> 495217 98.5 26086.8 182.8
>>
>> Here are the results doing the same test on the RAID-5:
>>
>> impala# ./Bonnie -d /usr
>> File '/usr/Bonnie.30972', size: 104857600 Writing with
>> putc()...done Rewriting...done Writing intelligently...done
>> Reading with getc()...done Reading intelligently...done
>> Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done...
>>               -------Sequential Output-------- ---Sequential
>> Input-- --Random--
>>               -Per Char- --Block--- -Rewrite-- -Per Char-
>> --Block--- --Seeks---
>> Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
>> K/sec %CPU  /sec %CPU
>>           100  7478  7.7 10727  4.3  7250  3.2 101910 99.6
>> 1464070 99.2 24067.2 180.6
>
>
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