Marc SCHAEFER <[EMAIL PROTECTED]> wrote:
> Now, RAID5 on the same 7 disk set:
> -------Sequential Output-------- ---Sequential Input--
> -Per Char- --Block--- -Rewrite-- -Per Char- --Block---
> Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
> 2000 16241 79.7 43569 42.0 19304 46.6 24004 92.0 68733 82.8
Now, that's interesting. It's not THAT bad (43.5 MByte/s writing,
68.7 MByte/s reading). However, what puzzles me is that my CPU is mostly
idle when I would expect it to generate the parity.
For 43 MByte/s of DMA out from RAM, we have the processor reading
at 43 MByte/s from the RAM, and writing at 6 MByte/s. From the RAID0
result, I would have expected 85 MByte-s - 1/7, which is around
70 MByte/s.
