[Gluster-users] Switch recommendations

[Dan Bretherton]

Thanks for the advice Peter,
> You could get a cisco switch that supports cut through instead of
> store-and-forward, for lower latency.
Interesting option, but those cost ~£10K and are out of our price range 
unfortunately.  The "cut through" switching technology is also available 
in Dell's new Force 10 range I believe.

> Other than that, compare the port to port forwarding times and see if
> there is a difference between the switches you are looking at (probably
> not) and make your decision based on that.
You're right, there isn't much of a difference between the forwarding 
rate of the 5548 and the 6248, both are about 100Mpps.  They also have a 
similar bandwidth of about 180Gbps.  However the 7048 does better on 
both measures, with forwarding rate of 160Mpps and a bandwidth of 
224Gbps.  Unfortunately the 7048 costs five times as much as the 5548, 
and I don't know if the users would notice any difference at all.  I 
expect some would and some wouldn't.

-Dan.

On 01/27/2012 01:48 PM, gluster-users-request at gluster.org wrote:
> Date: Fri, 27 Jan 2012 14:16:36 +0100
> From: Peter Linder<peter.linder at fiberdirekt.se>
> Subject: Re: [Gluster-users] Switch recommendations
> To:gluster-users at gluster.org
> Message-ID:<4F22A3B4.8000008 at fiberdirekt.se>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> You could get a cisco switch that supports cut through instead of
> store-and-forward, for lower latency.
>
> Other than that, compare the port to port forwarding times and see if
> there is a difference between the switches you are looking at (probably
> not) and make your decision based on that. Consider connecting
> everything to two switches, for failover in case a switch breaks?
>
> On 1/27/2012 2:04 PM, Dan Bretherton wrote:
>> >  Dear All,
>> >  I need to buy a bigger GigE switch for my GlusterFS cluster and I am
>> >  trying to decide whether or not a much more expensive one would be
>> >  justified.  I have limited experience with networking so I don't know
>> >  if it would be appropriate to spend ?500, ?1500 or ?3500 for a 48-port
>> >  switch.  Those rough costs are based on a comparison of 3 Dell
>> >  Powerconnect switches: the 5548 (bigger version of what we have now),
>> >  the 6248 and the 7048.  The servers in the cluster are nothing special
>> >  - mostly Supermicro with SATA drives and 1GigE network adapters.  I
>> >  can only justify spending more than ~?500 if I can be sure that users
>> >  would notice the difference.  Some of the users' applications do lots
>> >  of small reads and writes, and they do run much more slowly if all the
>> >  servers are not connected to the same switch, as is the case now while
>> >  I don't have a big enough switch.  Any advice or comments would be
>> >  much appreciated.
>> >
>> >  Regards
>> >  Dan.