January 31, 2015 at 7:40 pm
We are planning on upgrading to SQL 2012 in the near future. Our current config is as follows:
SQL 2005 cluster in Active/Passive mode. Log-shipping to a secondary datacenter 500 miles away
Our entire environment is running on VMWare 5.5 with HA option - 4 hosts with 196MB RAM each
System is OLTP and supports about 2,000 users, but typically we only have about 100 or so online at any given time - performance is not currently an issue - plenty of RAM and CPU available
Storage is two Equalogic SANs grouped together to act as one - so plenty of redunancy there
Primary application supported is mission-critical.
We moved to VMWare in 2011, and since that time we have had zero SQL cluster failovers. In fact, the only SQL failure we've had was soon after initial deployment everything shut down b/c whoever set up the service account forgot to set the password to not expire...DOH!
So my main question is: given that we are in a VMWare HA environment, is clustering necessary? I know that many will probably suggest that SQL would run better on a dedicated machine but we're not ready to make that jump yet. If it were running on dedicated hardware clustering would be a no-brainer.
In evaluating our current setup, I'm looking for failure points:
Storage - as I stated we have two SANs, so failure of the entire system is unlikely
Server Hardware - with VMWare we should be protected from motherboard/CPU/RAM/etc failure
Networking is covered - multiple NICs, multiple switches each with dual power supplies, etc.
I guess the main weak link if not clustering would be OS failure due to a bad update or some other issue - we do run full OS backups on the weekends and nightly differentials, although restore from tape would be time consuming to retrieve from offsite storage. SQL has fully nightly backups to disk and transaction log backups every 30 minutes and shipped
We can failover to the DR site in about 30 minutes if it really hits the fan.
I'm looking at the high-availability options for 2012 but am not as well-versed as I should be yet.
Sorry for the long post - any insight would be greatly appreciated.
February 1, 2015 at 7:20 am
RamoneThePoolGuy (1/31/2015)
So my main question is: given that we are in a VMWare HA environment, is clustering necessary?
A windows cluster on VMware has restrictions, you can't easily migrate the cluster VMs. In the Windows cluster the OS is protected where in VMware it is not.
RamoneThePoolGuy (1/31/2015)
I guess the main weak link if not clustering would be OS failure due to a bad update or some other issue - we do run full OS backups on the weekends and nightly differentials, although restore from tape would be time consuming to retrieve from offsite storage.
Yes, OS failure is an issue but given the time it takes to deploy and configure a VM shouldn't be an issue
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