I've got an Adaptec Serial ATA RAID 21610SA Controller card with 6 pairs of
RAID1 disks attached.  The card is rated at 1.5Gbps.  Writing to one pair, I
get about 30MB/s.  Writing to 2 pairs at the same time, I get a total of
40MB/s.  I get 40MB/s when I right to 3,4,5, or 6 pairs at the same time.
It seems 40MB/s is the hard limit for this card.  I was hoping to get
something close to 6*30MB/s = 180MB/s for the system.  Any ideas?

[ Post a follow-up to this message ]

In article <6MIke.1$l1.0@dfw-service2.ext.ray.com>,
"nospam" <nospam@nospam.com> wrote:

> I've got an Adaptec Serial ATA RAID 21610SA Controller card with 6 pairs o
f
> RAID1 disks attached.  The card is rated at 1.5Gbps.  Writing to one pair,
 I
> get about 30MB/s.  Writing to 2 pairs at the same time, I get a total of
> 40MB/s.  I get 40MB/s when I right to 3,4,5, or 6 pairs at the same time.
> It seems 40MB/s is the hard limit for this card.  I was hoping to get
> something close to 6*30MB/s = 180MB/s for the system.  Any ideas?

Is the card PCI-X? Is it in a PCI-X slot? Does the card provide
individual channels for each drive? How fast is reading? Presumably,
RAID-1 will be slower writing than reading. How fast is the computer? If
you put this in a system with 256 MB of RAM, that will certainly impact
performance. Finally, how did you make these speed calculations?

[ Post a follow-up to this message ]

What OS are you using? Have you explored filesystem block size? Depending on
the type of I/O and/or application its possible you are generating a lot of
I/O with too small a block size.


"nospam" <nospam@nospam.com> wrote in message
news:6MIke.1$l1.0@dfw-service2.ext.ray.com...
> I've got an Adaptec Serial ATA RAID 21610SA Controller card with 6 pairs
> of
> RAID1 disks attached.  The card is rated at 1.5Gbps.  Writing to one pair,
> I
> get about 30MB/s.  Writing to 2 pairs at the same time, I get a total of
> 40MB/s.  I get 40MB/s when I right to 3,4,5, or 6 pairs at the same time.
> It seems 40MB/s is the hard limit for this card.  I was hoping to get
> something close to 6*30MB/s = 180MB/s for the system.  Any ideas?
>
>

[ Post a follow-up to this message ]