My message :
>Hi managers,
>
>I planing to buy two alpha DS20e and two DS10 all in the same cluster.
>
>New, with TruCluster 5.1a is the choice between the memory chanel and >ethernet at 100mb.
>
>The memory chanel is an expansive solution, I ask the vendor for the >ethernet solution and he told me that this is not a good choice for >performance .
>
>The question :
>
>Can you comfirm me the impact of this choice on the performance of my >system. Is it (Memory Chanel) a vendor choice for making more money??
>
>Thank's
>Jeff
Thank's to all.
Lot of responses but there is no concensus, in the fact it depend of the application, In my case I have the money , I will take no chance .I join the message of "Dr. Thomas.Blinn" .
He wrote :
I'm sure you realize that no one on the tru64-unix-managers mailing list
is going to be able to give you an informed answer to your question.
You are correct, Memory Channel hardware is quite expensive. Since your
DS10 systems come with 100Mbit Ethernet on the motherboard, and there
are relatively inexpensive dual- and quad- channel 100Mbit Ethernet
cards available for the DS20E, you would have a much more cost effective
solution using Ethernet as the cluster interconnect (CI).
Since I know NOTHING about your workload, I can't tell you what impact
that choice would have on performance. The Memory Channel hardware is
capable of doing certain kinds of operations with very low overhead; it
has higher data transfer throughput than 100Mbit Ethernet and better
supports distributed disk and tape I/O. I don't personally know if it
would actually work in your configuration on all the system, and you'd
need to figure that out. But if you need the maximum performance for a
four node cluster, it is probably the way to go.
Of course, you've said NOTHING about the I/O connectivity that you plan
to have, that is, what systems connect directly to what disks. If you
plan to use local storage on ALL of the systems (it is possible to do
it that way), then ALL of the "off node" disk traffic is going to go
through the 100Mbit Ethernet, and the cluster file system protocols are
more reliable than NFS but not much different in terms of throughput
for the data. Plus, there is other traffic that will share the wire,
and some of that traffic is cluster bookkeeping operations that use
less system resources when done with Memory Channel hardware.
To summarize, without knowing A LOT MORE about your real workload and
how you propose to configure the systems, it's impossible to tell you
whether the Memory Channel hardware is worth the cost. If it were me,
I'd probably go with the 100Mbit Ethernet but budget for moving to the
Memory Channel hardware if I felt the performance wasn't meeting the
needs. I'd also take into account that TruCluster Server is already
being tested with gigabit Ethernet, and that newer less expensive GB
Ethernet adapters are not real far away from release, and that once
GB Ethernet is verified as working correctly, I might be able to move
to GB Ethernet to address bandwidth concerns. I'd also consider using
shared storage, either parallel SCSI or a FC SAN approach, to get the
I/O bandwidth bottlenecks removed, if I could get storage adapters to
implement the shared storage farm that would work in both system types,
the DS20E and the DS10.
Tom
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Direction de l'informatique
Service de la Technologie.
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Received on Mon Sep 17 2001 - 13:09:02 NZST