I posted a query about connecting large amounts of disk storage to multiple
Digital Unix machines at high speed.
Thanks to the following people who replied:
Khalid Paden <khalid_at_interaccess.com>
Bob Grosso <grosso_at_zk3.dec.com>
Raja Nagaraja <Raja.Nagaraja_at_actew.com.au>
alan_at_nabeth.cxo.dec.com
Guy Dallaire <dallaire_at_total.net>
Mike Sullivan <msulliva_at_emc.com>
Sid Fagan <fagan_at_large.fnal.gov>
Phil Rand <prand_at_paul.spu.edu>
Bryan Bahnmiller <bbahnmil_at_redwood.DN.HAC.COM>
norton_at_nrlmry.navy.mil
Alan Rollow <alan_at_nabeth.cxo.dec.com>
Bryan Bahnmiller summarised as follows:
: Get used to the poor way Unix does things. I was often horrified at
: the cavalier way Unix networks are put together.
Absolutely right. I'm amazed that Digital are trying to sell mainframe
class machines without anything better than SCSI. I can only hope that
they're going to upgrade their CI drivers for Unix, or turn the Memory
Channel into the new CI and release an HSZ controller which connects
directly to the Memory Channel hub (an option which would require the
Memory Channel limit of 8 nodes be raised to at least 32).
The answers pointed me in various directions, ranging from multiple SCSI
connections to dedicated NFS servers. There's certainly a number of ways
that lots of disk storage can be connected, but there's not many ways to
do so with reasonable performance. Even FDDI (supposedly targetted for
"high-performance cluster interconnects" <cough>) is only 11MB/sec which
means approximately 1MB/sec per machine in a 10 node cluster. Slow. The
GigaSwitch doesn't help either since the bottleneck is in the FDDI link
to the NFS server.
Possible solutions:
Buy 8400's to reduce the node count and use Memory Channel linked NFS
servers with multiple HSZs.
Use a GigaSwitch and buy at least 4 dedicated NFS servers to raise
the paltry 1MB/sec to about 4MB/sec. This isn't an easy solution as
the load has to be balanced between servers.
Plug 10 FDDI cards into the NFS server, 10 into the failover server,
and 2 into every machine.
Thanks to all for their suggestions.
--
steve_at_adam.com.au
Received on Fri Apr 04 1997 - 12:38:41 NZST