Re: Cheap RAID system recommendation?

In article <i9nvlu0o21r7eo9fdrmqqojlks4sml7eqv_at_4ax.com>, Rick Denoire <100.17706_at_germanynet.de> writes:
> Hello *.admin
>
> We are using a Sun's StorEdge A1000 in a Sun E3500 which happens to be
> extremely stow. Before we realized that it was so slow, we planned to
> buy a second one, but now we are looking for a different Raid system.
> The problem is that due to administrative reasons, we are not allowed
> to spend more money than it was once planned. So we are looking for an
> alternative that won't be more expensive that about 30 000 US$.
>
> This is what we need:
>
> - sustained transfer rate > 70 MB/s (not on paper, but *measurable*)
> - fastest SCSI flavor available (fiber channel would be way to
> expensive)
> - disks with 15000 RPM for small latency
> - 400 GB capacity total, equivalent to 200 GB in a Raid 10 conf.
> - no special features except a battery buffered cache
> - greater number of spindles are preferred over bigger disks
>
> This is a quite modest system I think. Be aware that a very fast
> system could even be inappropriate for this old fashioned machine (4
> SPARC 2 CPUs at 400 MHz), but of course, latency can never be small
> enough for scattered I/O operations.
>
> Would you recommend any specific modell for the mentioned machine?
> Dell? IBM? HP?
>
> Comments about your experience with different models are also welcome.
>
> Thanks
>
> Rick
>
> PS: By the way, nowadays some disks are so fast, that they can almost
> reach a sustained transfer rate of 70 MB/s in single mode!
>

The cheapest solution is to have disk striping between your two A1000, e.g. with DiskSuite. Each A1000 hooked on a separate SCSI bus, big stripe size (e.g. 512k). You wont get more than 50MB/sec with this config.
For > 50MB/sec on a Sun machine you _must_ have fibre channel. Because Sun's SCSI implementation is not good for high sustained transfer.

-- 

Michael Tosch / Master IS/IT Support
Ericsson Eurolab Deutschland GmbH
Tel: +49 2407 575 313