Best practice for data storage

[vmqts]

Hi All,

We have 4 ESXi 4.0 hosts runnning in our environment and have bought a storage array to used using iSCSI.Need all your inputs in order to carve out Luns to be assigned to the vSphere hosts?

We have ERP,Exchange 2007 and some windows servers, we use vMotion to migrate vm's.

Appreciate all inputs.

regards.

[idle-jam]

it depends on the storage system you have the type of disks and the interface of the connection too. anyway here i something worth referring.  http://www.vmware.com/technical-resources/virtual-storage/resources.html

[vmqts]

Thanks,

We want to know whether to use VMFS or RDM's? what is the best practice.

regards

[bulletprooffool]

Almost always VMFS - though RDM is good if you want to do things like create Microsoft clusters where one node is a VM and the other a physical.

VMFS allows partitioning of Datastore ondemand, as well as thin provisioning (so disk space saving)

We use RDM as little as possible.

good luck

[idle-jam]

VMFS as much as possible unless otherwise suggested by the application. it makes management easier too. frankly the performance difference between is very very little.

[Lee_Sargeant]

Hello,

I agree that in general VMFS is better than RDM unless you need a disk larger than 2TB.  The only exception I would say is if your storage supports VSS and you intend to use this for storage level snapshots and backup/restore.  If so then I would say RDM would be the better option.

Cheers,

Lee

[vmqts]

Thanks All.

I'm a newbie.....so should we create seperate Lun for different applications and assign to vSphere hosts or curve out a big Lun and assign as a full to vSphere?

regards.

[Lee_Sargeant]

I would not recommend individual LUNs if you are using VMFS.  Best practice is a maximum of 15 VMs in a single LUN so you may want to have a look at what you are virtualising and how many disks each VM will have.  Also if you are going to have some very high I/O intensive applications it may be best to keep those seperate.  RDM's have to be kept individual just the same as physical.

Regards,

Lee

[vmqts]

Thanks Lee.

Our current set up on our old storage array is set up as a Lun for C: and so on for each server, which makes management too complex and we want to avoid it with this new EMC array.

regards

[bulletprooffool]

Distribute LUNs so that you can run about 20 to 30 VMs off each Datastore that you carve.

have a think about how you plan on managing duplication / replication (if any) of these stores - as well as which VMs can be grouped together for storage outages.

also, consider DR / redundant VMs - rememebring that taking out your storage effectively kills all VMs on that storage (so for example . . do not keep BCP VMs on the same store as prod VMs)

also, rememebr there are datastore size limits just shy of 2TB per Datastore) - no point presenting bigger chunks!

Good luck.

[JohnADCO]

Some SAN manuafacturers will suggest a dedicated lun for Exchange servers over a certain mailbox count.   As stated above, your san manufacturer should be able to help some with the best way to carve things out.   If your using san automation for redundancy and/or have a small VM count?   The san redundancy automation management can be easier with more dedicated luns.

The best answers for your enterprise are not going to really be possible here.

[andershansendk]

If you want to use application-consistant-snapshots on the VM (ex. ASM for exchange with an equallogicarray), you have to mount a iscsi-volume from within the VM. It also makes it easy'er to use different snapshot-schedules for different servers.

[vmqts]

Thank you'll..

regards.