newbie question v3240/Ontap 8-7 mode/vmware

[NETAPPDOW]

Hello

We have v3240's running 8.1.3P2 7mode with 600gb SAS and 2TB SATA drives.   We are on VMWare 4.1U3 (2TB limit)

I'm "playing around" with VM disk configurations.   (I'm a bit confused, and looking for the best way to set them up)

We have a 2TB SAS LUN for VMWare VMs, with another 16TBs for other use. 

I have created both:

1) VM for Windows 2008 R2 F/P server O/S and additional virtual disk for User Data.  (Created virtual Data disk on same "Type VMWare" LUN and configured to keep with VM)  

2) Created Mapped Raw LUN (Type Windows 2008or later) for same Windows Server 2008 R2, and added it.

Which is the better scenario for Server Data disks?

Thanks.

Gregg

[YIshikawa]

You should make a choice from VMware perspective and your business requirements.
VMDKs on datastore is possibly slower than RDM, but can reverage VMware features like VM snapshot, datastore management or so.
RDM may be a bit faster than VMDKs, you have to manage each RDM LUNs. VM snapshot does not cover RDM.

[NETAPPDOW]

Ok, thanks........do you know what kind of data is suited to the two different types of disk groups noted before?

Basically we have F/P, Webservices, and some SQL DB's.

Most of this would fit on the SAS disk group.

Would the SATA disk group be used for backing up the SAS volumes?

Thanks.

Gregg

[ekashpureff]

NetappDow -

As Yishikawa mentioned, it's a business requirements question.

RDMs are a bit more work - creating the LUNs, mapping, and mounting them.

VMDKs are easy to work with.

RDMs may yeild better performance.

A typical use case would be with high performance databases.

SATA drives are often used for backups, or light IO storage.

The metric I use to determine SATA v SAS provisioning is IO density, expressed as max random IOs/TB of data.

( ~300 for your SAS drives and ~50 for your 2T SATA drives )

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff, Sr.
Independent NetApp Consultant http://www.linkedin.com/in/eugenekashpureff
Senior NetApp Instructor, IT Learning Solutions http://sg.itls.asia/netapp
(P.S. I appreciate 'kudos' on any helpful posts.)