I've been advised against hosting, say, Linux and Windows guests on the same SAN LUN.
Does anyone have any preferences/information either way?
We are hosting a variety of Windows / Linux VMs on the same LUN for some time now and have seen no performance degredation. I can think of no good reason to avoid doing this since VMWare is only taking over hardware calls. Linux and Windows make the same calls to write a sector to disk.
We are talking about a SAN LUN that is holding a VMFS, right?
In that case I think it makes more sense to make sure the I/Os are balanced across multiple VMFS LUNs rather than, e.g. put 2 high I/O Linux VMs on one VMFS and a low I/O Windows VM on another VMFS.
I really like to hear the argument(s) ...
Your LUN is not going to know the difference. As stated just make sure you do not group too many disk-intensive VM's all together.
These are good guides on SAN design and configuration....
SAN Configuration Guide - http://www.vmware.com/pdf/vi3_esx_san_cfg.pdf
SAN Conceptual and Design Basics - http://www.vmware.com/pdf/esx_san_cfg_technote.pdf
SAN System Design and Deployment Guide - http://www.vmware.com/pdf/vi3_san_design_deploy.pdf
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