questions about raw device mapping (RDM)

[zhangfred_vm]

Hi Friends,

The raw device mapping (RDM) is introduced in the ESX 2.5, does it used in ESX 3.0?

[ko]

Yes, it is still in use.

[davidbarclay]

Yep, sure is. But I urge you to consider why you want to use them.

Dave

[zhangfred_vm]

Hi Dave,

Do you means it is not suggested to be used in ESX 3.0?

[ko]

It is recommended to use Virtual Disk whenever possible.

RDM is usually use when you want to implement MS clustering across boxes.

[davidbarclay]

No, but don't use them without understanding why. If you don't understand, stick with VMFS!

There is a common misconception that RDM performs significantly better than VMFS - not true.

However it is required for SAN tool access.

Lots of things to consider!.

Dave

[virtech]

Agreed there is no "real"performance benefit using RDM instead of VMFS....

[davidbarclay]

See my responses in this thread:

http://www.vmware.com/community/thread.jspa?threadID=73745&tstart=0

Dave