VMDK Best Practices... ?

[marshall28]

When creating vmdk's is it best to create a seperate vmdk for each partition you create or create a large vmdk and partition that within your operating system? What are the benefits/Cons and is it better to use thick or thin disks?

Windows 2003 and 2008 will be used in this scenario.

thanks

[vmroyale · Accepted solution]

Hello.

When creating vmdk's is it best to create a seperate vmdk for each  partition you create or create a large vmdk and partition that within  your operating system?

Definitely 1 VMDK per partition in Windows. That way you can quickly and easily grow them as necessary.

What are the benefits/Cons and is it better to  use thick or thin disks?

This depends on several factors. If you need to overcommit storage resources, then thin will let you. If you need to use VMware FT, then you will need thick disks. The performance characteristics can be found here: http://www.vmware.com/pdf/vsp_4_thinprov_perf.pdf

Good Luck!

[marshall28]

with one vmdk disk you can also grow them. are there any performance benefits?

[vmroyale]

with one vmdk disk you can also grow them.

This hasn't always been my experience. I've found that you can grow the last partition.

Performance benefits could be realized in placing the different VMDKs on different controllers and/or different datastores. The 1 VMDK per partition approach would allow this.

[marshall28]

yeah yur right. good clarification, thanks for the help

[marshall28]

Is there an advantage to moving the paging file onto another vmdk if using 2003 or 2008?

[rickardnobel]

marshall28 wrote:

Is there an advantage to moving the paging file onto another vmdk if using 2003 or 2008?

In theory it could be, if you have multiple VMDKs you could place them on separate LUNs which could separate IOs.

However, in my opinion, this is most likely not needed in these days. Windows does not swap as much as it is sometimes belived. (Much of this confusion because of an incorrect counter in Windows 2003 Task Manager "Paging File Usage" - which does not show paging file using at all....)

Check your VM first and use Performance monitor to see:

Paging file: Usage % = Determine how much the pagefile is used. With 2008 this is typically very, very low.

Memory: Pages / second = Shows (almost) the amount of in and out to the pagefile. However, it is not really true, but the best general counter to see swap activity.