Need help with buying our first SAN (never done this before)

[wasc]

Hi all, Hoping to get some pointers on where to look with getting our first San.

Basically we need two servers initially connected to a SAN, however the number of servers could potentially grow to 4 in the future. Can anyone give me any pointers on where to look. I've already left a message with our Dell account manager to give me a call back about the MD3000i which I believe supports iscsi but there may be cheaper or better options out there.

Thanks in advance.

 

[iaind]

What is it going to be used for?

 

[wasc]

What is it going to be used for?

Lol - I should have mentioned that shouldn't I.

It's going to be used for VMware ESXi. Effectively the 2 to 4 servers we'll have will be running VMWare images, which will be stored on the San. The vmware instances themselves will be performing various roles (some will be DC's, others will be MS TS servers, one will be running a lightly used SQL db. We're also considering testing Exchange 2007 on there as well)

 

[iaind]

For 2~4 servers an iSCSI solution will be the best bet, FC would be a waste of money.

There are DAS (direct attached) options but most will work with up to 3 servers only.

The HP kit, while good, has problems with VMWare so I'd stay clear of their MSA arrays. The Dell stuff is meant to be pretty good.

Make sure whatever you get has dual PSUs and controllers. For light use, you will probably get away with SATA disks but if you want to start scaling out to stuff like Exchange, it might be worth getting 15k SAS drives.

You want 2 good gigabit switches, the HP ones are very good value for money and these are what I use (2510G-24), I wouldnt scrimp and get anything cheaper like netgear..

Each controller should have 2 interfaces and you should connect each controller to both switches, this means you can have any cable/controller fail and it will still keep running. The servers should have a connection to each switch too, preferably on different physical NICs (I used one onboard and one port on an addin card)

The SAN I just purchased was a Sun 2510, which is actually made by Storagetek (owned by Sun). Populated with 12x146gb 15k SAS and dual controllers cost just over £5k which was a very good price and the switches cost about 500 each.

In terms of configuration, I went for a 4 disk RAID 10 for the system volumes/transaction log volumes, a 7 disk RAID 5 for data and a single global hot spare. The RAID10 will give best performance although is expensive in terms of £/gb - if you can afford to do 2 RAID 10 arrays for your size requirements then do.

I'd really reccomend looking at the Storagetek arrays, very good performance and value for money

 

[wasc]

Thanks for the long and informative reply. Appreciate you taking the time to help. I'll definately research those Soragetek arrays.

 

[CGrieves]

Late reply I know, but for Virtualisation I would really recommend a hardware-based SAN. My advice is always overspec, simply because once you realise the administration, recovery and management benefits of virtualisation, you'll probably feel inclined to move more production infrastructure to the virtual platform.

Also bear in mind with ESXi you'll miss out on some of the real benefits of VMWare on a SAN- you won't be able to use VMotion (moving live VMs between hosts) or Storage VMotion (moving physical data for VMs between storage) unless you buy appropriate licences.

 

[Baz]

For 2~4 servers an iSCSI solution will be the best bet, FC would be a waste of money.

There are DAS (direct attached) options but most will work with up to 3 servers only.

The HP kit, while good, has problems with VMWare so I'd stay clear of their MSA arrays. The Dell stuff is meant to be pretty good.

What kind of problems, we are looking at the MSA 2000 series SAN at the moment....

 

[iaind]

Have a look around the vmware forums, I was warned off them when I asked for advice there myself. General performance and reliability issues it seems