ESX 3.5.0 Update 3 Question

[timcwhite]

Good afternoon,

Currently I have 16 HP Blade Servers attached to an EMC Clarion cx600 Array. All 16 servers have access to 22 LUNS. Is there a maximum amount of LUNS that an ESX box can see? I assume it would be in the range of 254. What is the recommended maximum?

Thanks in advance.....

Tim

[MattG]

256, only 128 during install.

The main issue with going with a large number of LUNs would be management, since the assumption is that you would want all of your hosts to see all of the LUNs for clustering.

-MattG

[MattG · Accepted solution]

FYI, ESX 3.5 U4 was released a couple of days ago.

-MattG

[timcwhite]

Thanks Matt, We just upgraded to version 3.5.0 update 3 last week. Typically my managment likes to stay one version behind. ...

The problem that we are having is that we have historically created 550GB LUNS. Some of these LUNS have about 20 VM's on them. I have read that VMware/EMC recommends no more than 12 to 15 per LUN in order to avoid SCSI reservation errors. I'm trying to find the sweat spot between the size of the LUNS and the the number of LUNS. We are growing so fast that I can see this becoming a major management issue.

[MattG]

The SCSI reservations are a real concern. However, with Storage Vmotion you do have the flexibility to move VMs to another LUN if you are getting SR's. So you could push it to 15 VMs per and adjust down with Sv if needed.

-MattG