Multiple Datastores?

[L0cayta]

Hi there.

I am creating a configuration document on my up and coming VM project.

I'll be running x4 vSphere5 Enterprise hosts running on Dell R710's all connected to a Dell EqualLogic PS6100XS for thier shared iSCSI storage.

Looking at best practices and not knowing hte correct limitations of datastores... What's the best configuration here. Is it best to create a large Volume ( 7TB's ) and assign this to vSphere as it's storage...Or...

Create multiple datastores ( each 1TB in size ) for use with Storage vMotion?

Thanks,

J.

[a_p_]

IMO this mainly depends on the VM's workload. With a storage system which is capable to present LUNs over multiple controllers you may have a better performance with presenting the storage as multiple smaller LUNs/datastores.

André

[mcowger · Accepted solution]

Theres more to it than just the workload, IMO.

You need to consider that you generally get slightly (5-10%) better performance with more LUNs/datastores, just because there are more queues available.

Also, more datastores means you have more options for doing backups, tiering, etc.  Lastly, you also have more options for replication in the future.

I would *not* create a single, large 7TB datastore.  I'd be more likely to create a 7-10 smaller datastores and spread my VMs around on them.

[scottyyyc]

Also, it's worth considering different snapshop/replication scenarios, as EqualLogics do everything on the volume level. If you have everything clumped together in one giant volume, then you have to snapshot/replicate/smart-copy/clone everything together as one volume. If you split things into different volumes, you have the flexibility to organize VMs and necessary for different snapshot/replication scenarios (eg. file servers on a single volume and more agressive snapshotting).

Before v5, you didn't have the luxury of large volumes in vSphere (2TB max), so most people will have things split up in 1-2TB volumes anyway. But like the other have said, workload and other things come into play. A general rule I often hear thrown about is max 15-20 VMs per datastore.

[L0cayta]

Thanks guy's.

Great info there. I'll look tp split the volumes up as suggested and get a plan together on how i'll replicate.

[christianZ]

With ESX enterprise VAAI is supported here -so you have some kind of "acceleration" in the box . Create luns with ca. 2 TB. To many luns make the scanning slow (or very slow). (have here ca. 10 EQL boxes).

If you have you any bigger vm  there  (> 1TB) then you should  create a bigger lun (e.g. 4 TB).

Reg

Christian