MS SQL Server 2008 failover clustering using VMware ESXi HA

[albertwt]

Hi All,

I'd like to build highly redundant SQL Server 2008 database and Infrastructure monitoring software for both my production and DR environment, I wonder if this design below is make sense and can provide me with sufficient redundancy at any level ?



My goal is that when the Production site is having a problem, the user can use the monitoring application from DR site as automated fall back plan.

Any kind help and suggestion would be greatly appreciated.

Thanks.

[andrew-virtusolve]

Assuming the two sites are in separate physical locations, you will not get reliable HA across the link, you would need to utilize Site Recovery Manager and the appropriate storage plugins.

You certainly won't be able to geo-cluster SQL in this way using CAB (Cluster Across Boxes) as this requires Raw Device Mapped LUNs on shared storage between the two nodes. Within the same site, with a number of tweaks you could get something similar working, but its a fair bit more complex than as described above as if your VM's are sat on a HA enabled cluster there is extra bits of configuration required (such as setting anti-affinity rules on the VMware cluster)

Alternatively you could look at replicating just the virtual machine files without the SQL cluster to the second location using some EMC plugins that quiesce the database and synchronise the block level changes, but with a highly transactional SQL DB this would be difficult to ensure its working. Your best bet would be to backup to the remote location using a vStorage API compatible backup solution and then bring the backup up if Site A ever fails.

To summarise, what you are trying to achieve is very difficult and comes with lots of gotchas, if you want availability across two physical locations VMware Site Recovery Manager is the way to go.

[apaton]

Hi All,
I'd like to build highly redundant SQL Server 2008 database and Infrastructure monitoring software for both my production and DR environment, I wonder if this design below is make sense and can provide me with sufficient redundancy at any level ?

My goal is that when the Production site is having a problem, the user can use the monitoring application from DR site as automated fall back plan.

Just some thoughts.

How will the SQL2008 databses updates get transfered to the DR box? . I do see that you have EMC snapshot replication which can move data typically on a hourly basis. EMC replication is usually implemented alongside VMware's SRM. SRM is a BIG RED BUTTON solution, and not automated!

Have you considered MS SQL Mirroring functionality as an alternative? SQL Mirroring can be automated if an appropriate witness server is provided. If you have high latency network links (WAN) then you should consider High Performance mode without automated failover.

Andy

[albertwt]

Ok, now i decided to re-think and draw again from scratch as previously it was my idea at 1 AM, so it seems that Failover clustering on top of VMware HA is too complex and slight downtime ~ 5 mins during the failback/server restart is acceptable for me, therefore I have now decided to go with SQL Server 2008 Mirroring HA (see the attached).

SQL-MirrorHA.jpg

the only single point of failure is the Witness VM (which runs SQL Server 2008 Express) if you can suggest any other placement then that'd be great.