Michael S. Zick wrote:
>
> The true advantage of a hardware card, is you only read/write
> the storage data once over the PCIe link.
>
I agree in theory, but I have been desperately disappointed with a two
3Ware cards of various generations. They struggled to get read or write
performance to match a half that of a single drive in a 4 drive raid5
config. Some of the limitations looked very much like those of the PCI
bus and indeed 3wares benchmarks suggested that you needed faster than
PCI to get >20-40MB/sec out of their cards (ugg). To me this looked
very much like the data was being transferred too many times versus
theory (also I discovered later that nearly all these hardware cards
can't do xor fast enough to keep up with a sensible modern disk, hence
software raid5 can often be faster because you aren't lagging on the xor
engine...)
I think the safe benchmark is all in software and be very cautious of
these hardware SATA cards. That said, the various scsi cards I have
tried absolutely scream. Why there are only cr*p sata hardware cards I
just don't understand?
Oh well
Ed W