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I'm looking at getting 3 hosts and a SAN set up with iSCSI for a VMware envoroment and have had several companies come to us with suggestions (small team and will need help with implementation). They have suggested an IBM setup using 2x 4 port 1GBE iSCSI cards on the SAN which is a DS3524 and then running a Cisco 2960S stack using 6 connections per host.

I went away and came back with a solution (for the same price) using 2x 2 port 10GBE iSCSI controller SAN which is a Dell 3620i using a Cisco 2960S stack with 2x 10GBE ports each and using 8 connections per host for improved performance. They can't match this in terms of price and have suggested the IOPS would be less in this configuration due to less channels on the SAN controllers (8x1GBE vs 4x10GBE). Are they talking rubbish to try and get a sale? Couldn't find much online but wanting to make the right decision.

I can post the full hardware specs of this solution if required.

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Interesting question. Well you know what, it's most likely there won't be a noticeable difference because the network is unlikely to be the bottleneck! So I'd probably go with the 2x2port 10GBE if the price is the same. You'll have greater headroom with 10GBE than with 1GBE. I doubt you'll regret buying the higher spec 10GBE. – Matt Jun 13 '11 at 0:07
I think the cisco 2960 is an oversubscribed switch with a total backplane speed of 32gb/sec. You really don't want to oversubscribe your storage network. There are plenty of switch vendors out there who will sell you something that is line-rate for all ports... – chris Jun 13 '11 at 0:20
It's been suggested I look at the 6224 switches opposed to the 2960, how does this compare? Do you have any other suggestions I could perhaps look at? – Daniel Jun 13 '11 at 0:25
It looks like the 6224 is a line-rate switch, so that's good. I've used Nortel, Extreme, and Enterays switches -- they often use exactly the same chipset but use their own software on the switch and there are huge differences in the quality of the software. Fortunately, if you're doing pure L2 you won't need to worry about that too much. If possible, get your vendors to each loan you the equipment they want to sell you and implement it with both and load-test both. Regardless, you want 10gig if you can get it. – chris Jun 13 '11 at 1:07
up vote 2 down vote accepted

Let's see 8 x 1Gb is 8Gb... 4 x 10GbE is 40Gb.... now... those controllers are probably active passive, which means its really 4Gb vs 20Gb. They're blowing smoke up your ass.

To same some additional money, check out the Dell 6224 switches, you can stack them AND add two 10Gb ports to each and will probably smack the Cisco around on price. That leaves you 24 ports one each switch for iSCSI for VMware hosts.

have you looked at the equallogic PS6010 for SAN? or is that out of your price range?

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Also, I really don't think you'll need 8 x 1Gb connections per host, 4 should do the trick, make sure jumbo frames and flow control are enabled on all ports that will carry iSCSI. – SpacemanSpiff Jun 12 '11 at 23:52
Thanks for your help :) I was actually planning on using a 6224 stack for LAN traffic and split the SAN traffic on to the Cisco stack. Is this overkill? I was going to use etherchannel hence looking at Cisco? Is this not needed at all? – Daniel Jun 12 '11 at 23:57
Also I have not looked at the PS6010 SAN however the 3620i is reaching the limit of my budget. What are the advantages of changing if you don't mind me asking? – Daniel Jun 12 '11 at 23:59
lol, Blowing smoke. I can't help but agree. – Matt Jun 13 '11 at 0:07
I'm not familiar with the MD, the equallogic has some nice vmware integrations, snapshotting, replication, no features are locked down. The Dell switches do LACP (link aggregation) just fine, but I wouldn't use LACP with iSCSI, round robin multipathing will utilize all the links nicely. Ideally iSCSI traffic is on an isolated switch stack, but if you're on a budget you'd have to gauge whether you think you can overwhelm the backplanes of the switches, the Dell stacking kit will provide a 24Gb interswitch link. It won't forward packets any better or worse than Cisco. – SpacemanSpiff Jun 13 '11 at 0:08

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