> I've been looking at the DPT SmartRAID/Cache V family but the only
> reports I've seen to date are of far from brilliant performance --
I tried the DPT PM15554U2 and the AMI Megaraid both connected to 3 18 GB
disks, 512 MB ram, Dual PIII @ 450 MHz.
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
With the DPT PM1554U2 (low end version, 4 MB ram):
1*1024 3699 55.7 4967 6.2 3547 8.1 6304 87.8 19943 19.8 270.8 7.6
1*1024 3881 50.2 4238 5.3 3538 7.9 5688 78.9 19873 19.4 344.4 9.6
1*1024 3833 49.1 4941 6.3 3590 8.0 6120 84.8 19831 19.3 294.9 9.1
1*1024 4702 72.2 4955 6.3 3058 6.8 6136 84.8 20286 19.2 288.4 7.4
With the AMI Megaraid (system was under some load):
1*1024 5426 83.6 13444 19.6 4958 15.0 4735 69.8 11212 16.7 121.8 4.9
1*1024 5437 83.9 12931 19.4 4345 13.7 5383 77.9 10867 15.2 121.7 5.3
1*1024 4955 76.2 13613 20.2 4371 13.5 4554 67.2 12902 18.9 178.7 6.0
1*1024 5726 87.3 13916 21.2 5097 15.6 5864 85.7 19635 28.2 158.0 6.4
Just as a comparison the DPT controller on a non raided disk (same
system):
1*1024 4787 77.6 9323 18.8 3608 11.6 5503 79.2 9899 13.3 124.6 4.8
1*1024 5455 90.9 11316 17.6 3626 11.7 5196 74.6 10308 13.9 128.9 4.2
1*1024 5426 90.4 11416 22.8 3627 12.0 5534 79.8 10265 13.3 125.4 4.8
1*1024 5454 91.2 9476 18.7 3581 11.6 5410 77.4 10300 13.9 135.1 4.9
Setup was easy just plug and play. But performance gain is not really
stunning.
I think the low cost versions don't do a good job performance wise. I
guess putting in some more memory on the controller might increase
performance a bit (DPT writing is extremely slow). But again for about
600$ you don't get a performance boost but more reliability. So either pay
more for the hardware solution or use software raid and pay the time you
spend to set it up.
Klaus
