suggestions for SATA RAID cards

[Mark Kirkwood]

Steven Hartland wrote:
> Mark Kirkwood wrote:
>>
>> If you are using RAID0|5, then something is slowing you down (possible
>> clash between disk firmware and the Areca, or unfortunate choice of
>> strip chunk size).
> 
> Dont know which test I was remembering but just did a quicky:
> OS: FreeBSD 6.1
> RAID: 5 on 5 * 400GB Seagate
> Controller: HighPoint 1820a
> CPU: Dual Opteron 244
> RAM: 2Gb
> /usr/bin/time -h dd if=/dev/da0 of=/dev/null bs=1048576 count=10000
> 10000+0 records in
> 10000+0 records out
> 10485760000 bytes transferred in 44.887239 secs (233602250 bytes/sec)
>        44.88s real             0.03s user              2.40s sys
> 
> In comparison:
> OS: FreeBSD 5.4
> RAID: 5 on 6 * 300GB Seagate
> Controller: Areca 1120
> CPU: Dual Opteron 248
> RAM: 4Gb
> /usr/bin/time -h dd if=/dev/da0 of=/dev/null bs=1048576 count=10000
> 10000+0 records in
> 10000+0 records out
> 10485760000 bytes transferred in 81.598938 secs (128503633 bytes/sec)
>        1m21.60s real           0.00s user              2.69s sys
> 

Hmmm - I've found that FreeBSD 6.1 is a considerably better performer 
than 5.4, so that is not helping the comparison above.

Another thing to check is that both systems have the same vfs.read_max 
    sysctl tunable, as that makes quite a difference on RAID systems!

If you have the time to keep playing with these machines, it might be 
interesting to try block sizes other than 1M - could expose different 
behavior too!

Cheers

Mark