Upgrade ESX 3.5 environment from local storage

[Twincam]

Hi

Today we run ESX 3.5 Foundation on three Dell PE2950 servers. 2xQuadCore CPU, 8GB RAM and we are using 4x146GB SAS 15k local storage in Raid 1+0 and Raid 5 configuration for virtual machines. The VMs (around 5-10 per server) are everything from SQL2005 servers, Exchange 2003 FE, Share Point to low utilization IIS servers.

Since we are running out of diskspace and cannot expand or add virtual machines we are now planning the "next step". In any case we will add more RAM, but should we just add a DAS storage like Dell MD1000 and fill it up with 15 SAS disks or should we go for a more expensive SAN solution(s) based on FC like CX-3, or a iSCSI solution on CX-3 or Equal Logic PS5000. A SAN solution would of course also give us possibility to upgrade to ESX Standard or Enterprise and use more advanced feautures HA, VMotion and so on.

What should I expect in perfomance difference between DAS and the different SAN solution if I use same number of harddrives and sizes? Any other thoughts?

Kindly regards

Pete

[JRink]

I was faced with the same thing in an HP environment. We have an HP DL380 G5 with internal disk storage only. We were running out of drive space on the server and I considered a SAN for the environment, but, the cost of the SAN vs the cost of a DAS made us lean towards the DAS. Not to mention, if we went SAN, and wanted to utilize the extra features such as VMMotion, HA, etc. It would not only cost us a SAN, but another server, etc. And, since our original goal was "We need more storage" and not "We need more storage and VMotion and HA features", it make more economical sense to go DAS. For us.....

In another environment, we went SAN because we thought there MIGHT be a chance in the future of utilizing features such as VMotion and HA. However, we still haven't used those features and as it turns out, likely never will, so in hindsight, we might have been better off just getting DAS there as well.

Regardless, don't dismiss a SAN if you think VMotion/HA, etc. is the route you plan on go in the future.

[jitendrakmr]

Practically speaking you will see only minor difference in performance only if your VMs are using higher disk IO. In case disk IO is normal then performce wise there will be no difference. Even if Disk IO is higher for some VMs then you can give seperate LUN for such VMs to get the better performance with SAN.

Though SAN is more costly but it gives you advantage of using enterprise features like HA, DRS, VMotion etc which also improves the server uptime and reliability.

Thanks.

Jitendra Kumar

MCSE 2003, VCP, CCNA, ITIL Foundation

[lewisyu]

Obviously FC and iSCSI SAN cost much more than any kind of DAS. But the flexibility, scalability and features SAN can bring to you, especially in a ESX environment, absolutely out-weight the cost difference.