Adding storage to VM Best practice

[Phil_Ax]

I everyone I have a quick question, maybe someone can help me with this. Here's our environnement:

ESX 3.5 Update 4

Storage: SAN FC

We just added 2 Tb to our SAN and it created a 2nd vmfs volume. So now we have storage VMFS-1 and VMFS-2. Both 2 Tb each.

Here's my question: I created a new VM(FTP server) with a storage of 40Go (on VMFS-1). Now I want to add a new partition of 500Go to this VM. I have about 500Go left on the volume VMFS-1 so should I just add 500Go in size to the existing capacity in the VM settings? Or should I add a new hard drive to this vm(in edit settings) and create a new virtual disk and point it to my new volume (VMFS-2) that has noting on it yet? Is there a performance difference between the two methods?

Thanks for your help...

[bulletprooffool]

Use the second volume as it will leave you room to expand volumes hosted on the first store.

[Poort443]

I would also use the second datastore, as you don't want to completely fill the first. It's always good to have some free space left. You might want to snapshot a VM on you first datastore, and than run out of space quickly.. In your case I'd do a storage vmotion of your FTP server, and than add the second disk, also on the second datastore. From a management point of view I think it's better if all the disks in a VM are on the same datastore.

[admin]

I agree. You also need to account for snapshot space (if you use them). The performance comparison would favor the two VMFS datastores in most workloads but you probably would not realize the difference unless you are driving a lot of throughput. Each VMFS datastore has a separate Queue in addition to the VM and HBA queues that exist on an ESX host.

[Lightbulb]

I agree use the second VMFS volume. Also make sure you block size is 2MB or greater (http://itknowledgeexchange.techtarget.com/virtualization-pro/choosing-a-block-size-when-creating-vmfs-datastores/)

[Phil_Ax]

Thanks guys, I really appreciate your help.

[Phil_Ax]

I did a storage VMotion like Poort443 suggested and everthing went well. So now my FTP Server (c:\) is on the new volume (named:VMFS-2). Now should I only add new space to the VM (in edit setting hard drive1 add 500Go) or should I add a new hard drive and point it to the new volume (VMFS-2). What is the difference between the two methods. Am I correct in thinking that it's exactly the same thing?

Thanks again

[Poort443 · Accepted solution]

It's easier to add another disk. If you make your existing C: larger in ESX, you would still have to extend it inside the VM. You can't use diskpart for this since it's your system disk. If it's a 2008 server this could all be done from the gui. If I were you I'd add another disk and make it D:\. It's always better to keep your data separate from your system anyway.

[Phil_Ax]

Thanks again