Re: 3Ware 7506-8, anyone have any luck? I don't...

[Ming Zhang <mingz@ele.uri.edu>]

Can you explain a bit that with what kind of configuration you can get
that 770MiB/s performance? Thanks.

ming

On Fri, 2004-10-15 at 14:44, KELEMEN Peter wrote:
> [ Please do not address answers directly to me; I read the list. ]
> 
> * Scott T. Smith (scott@gelatinous.com) [20041015 11:21]:
> 
> > You know what, I think I was wrong -- we have the 8506.  Sorry,
> > my bad.  And ours is SATA, not PATA (is that the difference
> > between the 7xxx and 8xxx?)
> 
> Yes.
> 
> > There are other reasons the Highpoint is better than the 3ware,
> > including the fact that it instantly recognizes when you yank a
> > disk, unlike the 3ware which sits there for a while, and then
> > hard resets the entire controller (thus halting all disk io to
> > that controller for a couple of seconds).  3ware wrote me back
> > and told me it's supposed to do that!
> 
> Cannot comment on this one, never was a problem for us.
> 
> > Is the 9500 a PCI-X card?
> 
> No, it's 64-bit 66 MHz PCI.
> http://www.3ware.com/products/pdf/9000DS_041904.pdf
> 
> > [...] and we get the same crappy performance from that one too.
> 
> Define `crappy': I get 770 MiB/s read with 3x 3ware 9500S-8MI.
> (RAID00 hw-sw)
> 
> > Worse yet, the 9xxx series wants to hijack your disks unless you
> > go out of your way to enable 'export JBOD' mode.  You can't take
> > a disk from a 9xxx controller and put it in a box with an 8506
> > -- the controller won't recognize it!
> 
> Have you tried zapping the first and the last megabyte of the
> disk?
> 
> > BTW I'm not talking about RAID or filesystem performance, I'm
> > talking about direct disk access, JBOD mode, using rather large
> > blocks.
> 
> Direct disk access gives me nominal disk throughput on 3ware.
> 
> > So really all I want is multiple controllers on a single card.
> > To that end, the 1820a works great.  I figure we'd all be
> > running software RAID anyways ;-)
> 
> As I said, attractive pricing.  Cannot get stellar hardware RAID
> performance with crappy chipsets. :-)  There's a turnover point
> where you are killed by PCI bandwith limit when using a lot of
> disks.
> 
> Peter