topic Re: Multi-site SAN with only 10MB connection in StoreVirtual Storage

Multi-site SAN with only 10MB connection

AB_1234 — Mon, 26 Dec 2011 09:28:50 GMT

Hi Guys,

I need a little help,

I have 2 P4500 with total 4 nodes, 2 nodes at main site and 2 at DR site, I need to make a replication between main and DR site, and the connection is only one link with 10MB between the sites

so what is the best option here:

Multisite SAN configuration with Raid-10 (synchronous): will it be ok to use 10MB network link between the 2 sites? - more preferred

or make a remote copy (asynchronous), can we make the remote copy every 10min, i tried but it did not work, any idea how can make it work - if it is possible?

regards,

Re: Multi-site SAN with only 10MB connection

Dirk Trilsbeek — Mon, 26 Dec 2011 13:08:37 GMT

a multisite-san with only 10 MBit bandwith would be incredibly slow on writes and during resync, not to mention the response time, which would probably be too high for a multisite-san. I'd go for the replication.

Re: Multi-site SAN with only 10MB connection

Bart_Heungens — Mon, 26 Dec 2011 19:47:29 GMT

Hi,

This will not work (well)... You shoud count for 50 MBps per 2 nodes... In your case I should go for a 2Gbps connection...

So I would go for the asynchronous solution...

Kr,

Bart

Re: Multi-site SAN with only 10MB connection

AB_1234 — Thu, 29 Dec 2011 06:43:37 GMT

Thank you Guys,

i manage to do the async already, but 10min will not work with P4000, you need to use 30min as a minimum for each snapshot taken.

Thank you Bart :) ..

Re: Multi-site SAN with only 10MB connection

bryan_hadzik — Tue, 03 Jan 2012 21:01:01 GMT

The other guys are right about why not to do it, but I thought I would explain in detail a little more. When setup in multi-site, if you use network raid 10, we have to write the block to both sides. We don't tell the server the block is completed writing until both sides have it. You could write it to the local side very quickly, but if the latency to the other site is over 2ms, it would start to slow everything down, even on the local side. Latency is sometimes more of a barrier than bandwidth.