[Gluster-users] Switch recommendations

[Harald Stürzebecher]

2012/1/27 Dan Bretherton <d.a.bretherton at reading.ac.uk>:
> 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.

Are there some network admins or someone with networking experience
you could talk to?
Do you use the management functions that your current switches support?

> 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.

How many server and clients do you have now?

Do you plan to increase the numbers in the near future?
In that case I'd suggest to get stackable switches for easier expansion.

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.

How are the servers and clients distributed to the switches now?

How are the switches connected to each other?

Can you tell where your bottleneck is?
Is it the connection between your switches or is it something else?

Could you plug all the servers and some of the clients into one switch
and the rest of the clients into the other switch(es) for a short
period of time? There should be a big difference in speed between the
two groups of clients. How does that compare to the speed you have
now?

Any advice or comments
> would be much appreciated.

What happens if one switch fails? Can the remaining equipment do some
useful work until a replacement arrives?
Depending on the answers it might be better to have two or more
smaller stackable switches instead of one big switch, even if the big
one might be cheaper.

I don't have much experience with network administration so I cannot
recommend a brand or type of switch.

I just looked at the Netgear website and googled for prices:
Two Netgear GS724TS stackable switches seem to cost nearly the same as
one GS748TS, both are supposed to have "a 20 Gbps, dual-ring, highly
redundant stacking bus".



Regards,

Harald