Assigning LUNs to VMware servers

[mistersparky]

Hey there!

 

We are running a mixture of Windows (2003-2008R2) servers both physical and virtual. The virtual environment is ESX 3.5 (we are planning on upgrading over the summer). On top of this, we have an HDS AMS2100 SAN.

 

We have a number of SAN LUNs assigned to our virtual servers. However, there doesn’t seem to be much in the way of consistency in how this is done. Some are mapped directly through the OS, some are configured through VMware as RAW device mappings, and some are configured as VMware virtual disks on datastores mapped to the VMware environment.

 

What are the pros and cons of each approach for both OS and data drives?

[Dave_O]

See this thread: http://www.edugeek.net/forums/thin-client-virtual-machines/87472-spindles-san.html

[apaton]

Some are mapped directly through the OS, some are configured through VMware as RAW device mappings, and some are configured as VMware virtual disks on datastores mapped to the VMware environment.

 

What are the pros and cons of each approach for both OS and data drives?

 

Pro and cons is all about management for me. VMFS are easier to visualise (vcentre)/manage/backup and the performance overhead is quite minimal compared to RDM (Raw Device Maps)

 

I always use VMFS datastores and only exceptions are in specific scenarios such as MS cluster/External Physical Host Access (non-vmware) and host controlled storage snapshots then I would use RDM.

 

Andy

[Dave_O]

There is no advantage to be gained by using raw in this environment. I would stick to vfms