Data Backup and Recovery

RDM or VMFS for SQL considering SnapManager, SnapMirror, and SRM


Currently, I have I have my production SQL servers running on physical blade servers in an MS cluster. We are looking at migrating the SQL servers to new VMs on VMware 5.1. I know that i have to split the luns into OS, System DB, User DBs, Logs, and SnapInfo. 

What I am trying to figure out what are the pros/cons and best option of either using RDMs or VMFS for SQL considering that I have to account for SnapManager, SnapMirror, and VMware SRM in the design. We are currently building our NetApp infrastructure so I am not able to do a usability test. I am reading all the Netapp literature on these scenarios but it's kinda confusing.

PDFs read:

- SnapManager 7 for Microsoft SQL Server

- SnapManager for SQL Deployment Guide

- Microsoft SQL Server and NetApp SnapManager for SQL Server on NetApp Storage Best Practices Guide

- Best Practice Guide for Microsoft SQL Server and SnapManager 7.0 for SQL Server with Clustered Data ONTAP

- Disaster Recovery of Microsoft Exchange, SQL Server, and SharePoint Server Using VMware vCenter Site Recovery Manager, NetApp SnapManager and SnapMirror, and Cisco Nexus Unified Fabric

- Deploying VMware vCenter Site Recovery Manager 5 with NetApp FAS or V-Series Storage Systems



I talked with a VMware tech regarding SRM and they said that for SRM, they don't care if we use RDMs or VMFS beyond the normal feature benefits of vmfs vs RDMs. So the only thing I'm trying to find out now is RDMs vs VMFS when using SnapManager, Snapmirror, and things like flexclone.




Did you ever get an answer to the whole RDM vs VMFS with SnapManager?


we have 2 Exchange 2010 SP3 Virtual Servers within our VMware farm. There is a separate exchange DB and a seperate front end hub transport server. All the disks for these servers are non-RDM VMDK disks. Will an implementation of Snap Manager work with this setup or do the disks need to be setup as RDM (physical or virtual) disks? 


Do all snap manager products (SQL, Sharepoint) require direct SAN disk access for them to work?


We will be using Snap mirror and snap vault to protect the VM integrity but what we were looking to achieve with the snap manager products was the granularity so we wouldn’t need to restore a whole VM in the case of a single user mailbox recovery for exchange or if we needed to restore a SQL database.




For Exchange, you will need to have the database and logs in RDM luns. SME doesn't work with VMFS mostly because of the Exchange team being the last to the party as I have heard from Netapp Engineers. We are going to do RDMs for our SQL servers that are going to be clustered via Availability Groups. 


The end decision for us was that I went to Insight and all the Netapp Engineers I talked to that work with SQL or VMware said it's better to do RDMs. The reason we are doing this is not because of day to day performance but during backups, a VMware snapshot will slowdown a highly utilized system because of the temporary file that is created. We have seen this with some of our systems. Since we can do host vmotion with the RDMs, we were more confortable with this approach. For our Tier 3 and QA SQL servers, we are using VMFS with Snapmanager. 


VVOLs should make this easier and should eventually remove the dependency on RDMs.


For snapmanager to work, you will need the luns to be on the Netapp so in that sense it is shared storage.