the performance of SAS is not better than SCSI in FreeBSD, WHY?

Ivan Voras ivoras at
Thu Apr 12 06:18:14 UTC 2007

Tzu-Hua Wang wrote:
>    Hi:
>    Thank you for your response.
>    Ther performance of your server is significantly better than mine.

Only in seek times, but this may be an artifact of RAID1. Do you use 
2.5" or 3.5" disks?

>    The SAS Chip of my HP ProLiant DL380 G5 is Smart HP Smart Array P400.

Mine was E200i.

>    It uses the FreeBSD driver ciss0

Same here.

>    I think that there is only one difference between your HP server and
>    mine.
>    I configure my SAS HD as RAID 0.
>    Will this affect the performance?

RAID should be much faster than RAID1 for the kind of tests diskinfo 

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