On Thu, Apr 19, 2001 at 04:20:09PM +0200, wojtek@3miasto.net wrote:
> > Speaking of IDE, the 3ware RAID card is an intersting alternative using
> > IDE.
> 
> how many channels does it offer per card, does it support RAID-5, does it
> have onboard memory and how much does it cost?

different models: 2 channels (U$ 150), 4 channels (U$ 260),
or 8 channels (U$ 430).

all support raid 0 and raid 1.

the 4 and 8 drive versions support raid5, raid1+0 (mirrors, then
stripe the resulting mirrors), and a hot-swap drive.

raid5 sucked at writing. e.g, 20MB/s writing raw disk, 20-25MB/s
writing to raid0, raid1, raid1+0, 5MB/s writing to raid5. reading was
pretty good on all, and scaled up as the number of drives became
available. i was getting ~ 20MB/s off 1 raw disk, up to 45MB/s off 4
disks in raid1+0.

in my experience of 12 months with s/w scsi raid, 5 months running
s/w ide raid, then testing h/w scsi raid and h/w ide raid, there
is a NOTICABLE difference between software IDE raid and the escalade
hardware IDE raid. Yes, i had each drive on separate ata66/100
controllers with software raid (with no slaves). the hardware raid
felt less `sticky'/`sluggish' under transactional load, which is what
most unix access is (rather than raw throughput).

I'm sure Thor Simon has posted on the lists in the recent past
about why IDE, even ATA100 IDE, sucks with > 1 device.