What would you do

[syn3rgy]

We are currently setting up a new vSphere 5 environments. What would you recommend for Datastores given the following scenario?

1 Datastore of 500GB

If you eventually run out do the following:

a) Create an extent

b) Create an additional datastore

1 Datastore of 500GB

Made up of 2x250GB one of which is an extent

If you eventually run out do the following:

a) Add an additional extent

b) Create a new datastore

What I am trying to find out is:

a) Would it be better to create multiple datastores of say 500GB

b) Would it be better to create 1 datastore made up of a few smaller extents (say 250GB each)

c) Would it be better to create 1 datastore made up of 2x250GB (one is an extent) and if more space is needed create a new datastore and repeat.

I’m in two minds about using extents as should of course one fail you could potentially lose everything on that Datastore, if you take one LUN offline, you will take the entire datastore offline.

While i do not intend to hit the maximum limit of datastores allowed what benefit would using datastores with multiple extents over using datastores without extents.

Thank you

Thank you

Rob

[PduPreez · Accepted solution]

Hi Rob

Best Practice is 1LUN = 1Datastore

I’m in two minds about using extents as should of course one fail you could potentially lose everything on that Datastore, if you take one LUN offline, you will take the entire datastore offline.

This is one of the reasons yes

What I am trying to find out is:

a) Would it be better to create multiple datastores of say 500GB

b) Would it be better to create 1 datastore made up of a few smaller extents (say 250GB each)

c) Would it be better to create 1 datastore made up of 2x250GB (one is an extent) and if more space is needed create a new datastore and repeat.

Out of this I can only recommend a) multiple datastores of say 500GB

Remember if you reach your Datastore capacity, you dont have to add an extend, as long as you can grow the LUN from the storage side, you can grow your Datastore from vSphere side and keep the ratio of 1 LUN= 1 Datastore

Please don't forget to award points for correct/helpful answers :smileylaugh:

[a_p_]

Since you are asking for opinions, here is mine.

Don't use extents anymore, it just adds complexity to your environment. Extents were needed to expand datastores before v4.0 and to overcome the 2TB limit before v5.0 With vSphere 5.0 the LUNs and datastores can have a size of up to 64 TB and can be grown without downtime.

Whether you want to use a single large datastore or multiple smaller datastores depends on the workload of the VMs and the capabilities of your storage system. If the storage systems has 2 controllers, you could present multiple LUNs using both controllers and thus load balance the traffic.

André

[syn3rgy]

Guys,

Thank you very much for your replies, very informative and very helpfull and greatly apprecaited.

I think I will be going with the options to avoid extents and a 1-1 ratio.

Thank you again.

Rob