[Gluster-users] Switch recommendations

[Peter Linder]

Putting all machines on the same switch will at least save a switch-hop, 
cutting latency by 1/3 in the ideal case which is an improvement. If it 
will matter for your application, I do not know :)

On 1/30/2012 6:45 PM, Dan Bretherton wrote:
> 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.