[wplug] RAID performance

[Michael Skowvron]

Patrick Wagstrom wrote:
> We've got a machine right now with 4x400GB Hitachi SATA I drives (model 
> HDS724040KLSA80S) connected to a 3ware Escalade 9500S 4 port SATA RAID 
> controller (128MB of ram on the controller).  These drives are 
> structured in RAID 5.

You don't mention anything about the system architecture.

The 9500S is a 66MHz, 64 bit card. That's good for about 400MB/sec max 
if you've got that kind of PCI bus. That's somewhat rare.

If you have it plugged into a "traditional" 33 MHz, 32 bit PCI bus, 
you'll never be able to get more than about 100MB/sec.

Mike S's PCI-X card is capable of 1 or 2 GB/sec depending on the model, 
so the bus will never be a limiting factor.

Michael