RE: Hitachi 9000 (was RE: 2GB or not 2GB )

  • From: "Keith Moore" <kmoore@xxxxxxxxxxxx>
  • To: kevinc@xxxxxxxxxxxxx
  • Date: Mon, 11 Sep 2006 17:10:28 -0500 (CDT)

I check my data and found it is actually 102 GB in 66 minutes for a rate
of 26 MB/sec for a full table scan. "Sequential reads" are much slower,
around 8-10 MB/sec.

Here is what I know about the architecture:
  Two Hitachi SANs
  2 SANs are shared by 4 Sun 15K servers
  Disks are 146 GB each
  Each disk split into 35 GB Logical Volumes
  8 disks in a logical disk group (Raid 5 w/ 128K stripe)
  2 HBA per SAN. I think 1Gb, but not sure
  Veritas file system
  56 GB read/write cache

I know Raid10 would be better, but Raid5 is the corporate direction. The
other problems seem to be that the disks are shared by multiple databases
and possibly the stripe size.

Any comments would be appreciated.


> That is 113MB/s.  You wouldn't happen to have 1Gb HBAs would you?
> Is this data striped across, say, 10 spindles?


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