>>>>> "David" == David Wetzel <dave@turbocat.de> writes:

>> I'd recommend
>> an external RAID controller.  It's a device with at least two SCSI
>> buses, typically.  It makes a bunch of hard drives on one side of
>> it look like one big hard drive on the other side.  The good ones
>> have battery-backed cache memory, which can do some wonderful
>> things for performance, especially with NFS.

David> Is such an device really faster than a Raidframe disk array
David> with the same disks on some Adaptecs?

In theory, yes.  That's only because of the cache, though; when you
send a write request to the "disk," it returns almost immediately
telling you that it succeeded.  This should do amazing things for NFS
(v2), because the client is required to keep a copy of the written
data until it gets a message from the server saying the data was
written to non-volatile storage.

Also, a good RAID controller will optimize the order of the writes
that are sitting in its cache.  That may or may not speed things up
significantly.

I've actually never done any good benchmarks, so all I know is the
theory.

Chris

-- 
-----------------------------------------------------cjones@math.montana.edu
Chris Jones                                          cjones@honors.montana.edu
           Mad scientist at large                    cjones@nervana.montana.edu
"Is this going to be a stand-up programming session, sir, or another bug hunt?"