SATA or SCSI drives - Multiple Read/write speeds.
Lombard, David N
david.n.lombard at intel.com
Tue Dec 9 10:03:12 EST 2003
From: Mark Hahn; Sent: Monday, December 08, 2003 3:18 PM
> SCSI: pro: a nice bus-based architecture which makes it easy to put
> many disks in one enclosure. the bus is fast enough to
> support around 3-5 disks without compromising bandwidth
> (in fact, you'll probably saturate your PCI(x) bus(es) first
> if you're not careful!) 10 and 15K RPM SCSI disks are common,
> leading to serious advantages if your workload is
> (mostly of small, scattered, uncachable reads, and/or
> writes.) 5yr warrantees and 1.2 Mhour MTBF are very comforting.
Very big pro: You can get much higher *sustained* bandwidth levels,
regardless of CPU load. ATA/PATA requires CPU involvement, and
bandwidth tanks under moderate CPU load.
The highest SCSI bandwidth rates I've seen first hand are 290 MB/S for
IA32 and 380 MB/S for IPF. Both had two controllers on independent PCI-X
busses, 6 disks for IA32 and 12 for IPF in a s/w RAID-0 config.
Does SATA reduce the CPU requirement from ATA/PATA, or is it the same?
Unless it's substantially lower, you still have a system best suited for
low to moderate I/O needs.
BTW, http://www.iozone.org/ is a nice standard I/O benchmark. But, as
mentioned earlier in this thread, app-specific benchmarking is *always*
David N. Lombard
My comments represent my opinions, not those of Intel.
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