Todd,

I am testing a Dell 2900 server hosting Windows Server 2003 Enterprise Edition (x86 32-bit) SP2, with a PERC-6i and 10 x 146 GB SAS 15 KRPM drives configured as 4 RAID-0 virtual disks (1 x 1, 2 x 2, 1 x 5). An application was tested on this configuration, and was found to perform worse than expected (given understandings and assumptions of RAID-0 performance).

IOMeter was then run on the same server for each disk size. The findings from these tests were:

- Sequential and random read throughput rates were about as expected for all disk sizes

- Sequential and random write throughput rates were significantly lower than expected for 2- and 5-disk RAID-0 virtual disks (yet were as expected for the 1-disk virtual disk)

- Write performance for 2- and 5-disk RAID-0 virtual disks were worse than for a 1-disk virtual disk

- Write performance for a 5-disk RAID-0 virtual disk was worse than a 5-disk RAID-5 virtual disk: up to 3 times worse for random writes and up to 11 times worse for sequential writes.

- No significant changes in the RAID-0 write performance resulted from the use of 64 KB NTFS allocation unit size or from 1 MB volume alignment

These findings lead me to suspect a possible defect in the PERC-6i firmware for RAID-0 support.

Has anyone else experiences these issues?


(to be continuted in next post - due to posting size limits).


Scott R.

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