RAID Cluster Size

Blast from the past: originally published in 2003. Testing RAID cards is a long and arduous process. The most difficult part was deciding on a standard cluster size for all cards. While the Promise cards can have from 8k to 2048k, Adaptec’s limit is 128k, and 3ware’s is 64k. All cards default to 64k cluster size, so who am I to argue? Just for comparison sake, I ran the Promise FastTrak100 with three cluster sizes to see the difference.

Blast from the past: originally published in 2003.

Testing RAID cards is a long and arduous process. The most difficult part was deciding on a standard cluster size for all cards. While the Promise cards can have from 8k to 2048k, Adaptec’s limit is 128k, and 3ware’s is 64k. All cards default to 64k cluster size, so who am I to argue? Just for comparison sake, I ran the [intlink id=”115″ type=”post”]Promise FastTrak100[/intlink] with three cluster sizes to see the difference.

Adapter WinBench 99 IO Meter HD Tach
High File Work- Data- Read Read Write CPU
Drive Configuration Cluster Business End Server Station Base Burst Average Average %
RAID 0 Two Disk 8 5220 6120 99.29 89.12 77.13 75.3 57273.8 2426.2 5.1
64 6270 10400 103.99 121.79 113.91 69.5 35164.6 28952.1 11.4
512 6250 17400 104.21 121.14 109.99 74.7 24572.1 28384.8 9.3
RAID 0 Four Disk 8 3960 3970 84.95 93.32 95.58 63.6 51357.3 1429.4 4.4
64 6000 9300 103.25 120.88 117.25 68.6 21714.6 30492.9 8.8
512 7040 19200 108.23 126.71 123.94 74.5 21338.7 29240.3 8.3
RAID 0+1 Four Disk 8 3960 3970 74.11 68.71 61.91 63.6 51357.3 1429.4 4.4
64 4680 3960 87.84 105.63 95.76 67.9 31950.1 1238.8 2.9
512 4770 3630 94.75 113.85 101.67 65.7 23630.1 1245.0 2.8

I’ve indicated best scores in a range with Bold face. I can’t account for the poor write scores with HDTach, although they were quoted in the December issue of Maximum PC as indicating their benchmark is not designed for RAID systems. All tests were run using the Test Platform.

On the two disk system 64k appears to be the clear winner. With four disks, 512k kills with RAID 0 and does well again with RAID 0+1.