Any advantage to keeping OS Apps and Page file on separate volumes

[proberts19]

We are migrating all our data from an EMC CX4-240 to Nimble CS300.

Our old configuration kept the C:\OS, D:\Apps and E:\Page File of each VM on separate datastores/LUNS mainly I think to try and get the best performance.

These datastores are shared by multiple VM's and we have a number of each type of datastore.

We also have separate datatstores dedicated to the application data which will be kept on separate volumes on the CS300

My question is, Are there any advantages to keeping this separation of the OS APPS and page file on different volumes when we storage vmotion the VM's to the CS300 or are we better off to keep all the VM disks on the same volume given that it will make restoration from snapshots easier.

[Valdereth · Accepted solution]

Having virtual disks stored on separate datastores/LUNS gives you the ability to align the Volume Performance Policy settings for the data that resides on it.  When it comes to OS and page file, I can't think of a compelling reason to place them on separate volumes, hopefully your VMs aren't paging too much.

Application data should be placed on a Volume with the performance policy (block size, compression, caching) that best suits it.  You'll find a lot of pre-defined policies, and when it doubt the 4k block size has got your back.

[rbrowne40]

The only advantage separating out the page files into a different volume is the ability to choose NOT to replicate that volume which may in turn reduce the amount of data being replicated between arrays.

[Valdereth]

This is a good point, I hadn't thought of replication traffic!

[nostratomas42]

Reduced Snapshot size.