Re: Linux SATA RAID FAQ

Alan Cox
2004-08-14T16:24:19Z

On Sad, 2004-08-14 at 01:31, J. Ryan Earl wrote:
> On the brightside, md raid5 is often faster than hardware raid5. At
> least on the 7000 and 8000 series of 3ware hardware; the 9000 series
> looks promising though. I haven't seen megaraid SATA numbers, and I
> don't know what happened to the SX8.

Be cautious what you measure. One of he problems until you reach PCI-X
is PCI bandwidth. Thus software md5 can look good but the moment its
combined with other PCI activity goes down the pan entirely.

> When the libata Marvell drivers come out, you'll have a cheap upgrade
> path for PCI-X boards if you want fast md raid:

Agreed. PCI-X will change a lot of this for boxes that are not very
cpu/memory limited.