Hi: When using 'dmesg' command, it shows that da0 at ciss0 bus 0 target 0 lun 0 da0: <COMPAQ RAID 0 VOLUME OK> Fixed Direct Access SCSI-0 device da0: 135.168MB/s transfers da0: 419946MB (860051248 512 byte sectors: 255H 32S/T 65535C)
Oh, my goodness. My SAS HD is only the SCSI-0 device. I think this is the major reason. Why? Can you give me a hand? Problem of configuration on the RAID Card? I am sorry, I am really new to the RAID system. Thanks 2007/4/11, Ivan Voras <[EMAIL PROTECTED]>:
Tzu-Hua Wang wrote: > Generally, the performace of SAS in FreeBSD is far worse than SCSI in > FreeBSD. > Is it normal? How can I do to improve the performance of SAS HD in FreeBSD? There's a huge number of possible reasons - unless you're testing the same controller (I think there exist SAS+SCSI controllers, I might be wrong), you can't conclude that the SAS interface is less supported. For what it's worth, I've got approximately the same numbers on DL380 G5, but I've attributed them to 2.5" small form factor drives. 2x 2.5" 10k RPM, CISS hw RAID1 2x 3.5", 7.5k RPM, soft RAID1 Full stroke 3.863 ms 5.942 ms Half stroke 3.929 ms 6.186 ms Quarter stroke 3.998 ms 5.700 ms Short forward 3.889 ms 4.060 ms Short backward 4.715 ms 4.748 ms Seqential outer 1.011 ms 0.167 ms Sequential inner 1.013 ms 0.177 ms Read transfer, outside 43.6 MB/s 61.2 MB/s Read transfer, middle 38.8 MB/s 54.8 MB/s Read transfer, inside 32.8 MB/s 34.9 MB/s The 3.5" drives were SATA in a different machine (Dell's). It might be that the CISS driver is unreasonably slow, which is kind of possible given the suspicious lower bound of about 1 ms in seeks. Maybe something is throttling the I/O rate?
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