Re: Consumer-grade vs enterprise-grade disk drives

On T, 2005-05-31 at 17:08 +1200, Mark Kirkwood wrote:
> Luke Lonergan wrote:
> > Tom,
> >
> > This is a story that is evolving. Anyone else use StorageReview? Great
> > comprehensive drive benchmarks:
> > http://www.storagereview.com/
> >
> > Check the comparisons between 15K RPM SCSI drives and the 2004 Western
> > Digital 10K RPM SATA (Raptor) drives. The Raptors are an interesting hybrid
> > of SCSI-related tech and desktop tech, and were some of the first drives
> > with SCSI-like command queuing TCQ/NCQ.
> >
> > I think the last remaining issue in moving to SATA for all enterprise use is
> > the lack of decent SATA controllers, though 3Ware (http://www.3ware.com) is
> > getting there:
> > http://www.3ware.com/link/pdf/Serial-ATA.pdf
> > http://www.3ware.com/products/benchmarks_sata.asp
> >
>
> Although the benchmark numbers are pretty good, they have only published
> (what looks like) results for sequential IO. It would be interesting to
> see the random ones, as this would tell us how effective the TCQ
> implementation is.
> RAID10

The following are from iozone results for 3Ware with 8 x WD 74G Raptors
on 1.6GHz Opteron and 2GB RAM

RAID10

"Throughput report Y-axis is type of test X-axis is number of processes"
"Record size = 8 Kbytes "
"Output is in ops/sec"
" Initial write " 1352.90
" Rewrite " 413.31
" Read " 369.01
" Re-read " 368.07
" Reverse Read " 355.94
" Stride read " 358.01
" Random read " 358.29
" Mixed workload " 360.55
" Random write " 359.80

RAID5

"Throughput report Y-axis is type of test X-axis is number of processes"
"Record size = 8 Kbytes "
"Output is in ops/sec"
" Initial write " 1178.55
" Rewrite " 145.91
" Read " 369.06
" Re-read " 364.37
" Reverse Read " 357.83
" Stride read " 357.79
" Random read " 358.04
" Mixed workload " 359.70
" Random write " 360.62

Seems to have either very low overhead for RAID5 or something else is
keeping RAID10 speed down.

--
Hannu Krosing <hannu(at)skype(dot)net>