Part Discussion, Part Question.
I am a SQL DBA, not a vCenter Admin. We recently installed vCenter 5.1 and our sysadmin team began a procerss of migrating hundreds of VMs to it from 4.1/5.0.
I'm not sure what that all entails but for quite some time, the vCenter application has been generating a lot of transaction logs.
We do trn backups every 15 minutes and these backup files are 400MB+...do the math and thats close to 40GB/day in trn backups.
First comment: I have seen the reccommendation to set the vCenter database to SIMPLE recovery mode in SQL Server. This will surely reduce the size of the transaction log file (LDF) as only the active transactions are kept. But when I see this advice on this blog, people are not considering that SIMPLE recovery mode means you can only restore the database to the point-in-time of the last full or differential backup. If you dont care about point-in-time recovery then SIMPLE makes sense for you. We want to be able to recover to a point-in-time so we use FULL recovery mode and transaction log backups.
Second Comment: Nothing "weird" is happening on the Database side. No long open transactions or log shipping or mirroring not working. I've checked the VLFs for the vc database and the log_reuse_wait flags and transactions are only waiting on the Log backup which is happening correctly every 15 minutes. They are getting backed up and removed.
The big question is what is vCenter doing that it has to generate so much log activity??
I've traced the database activity in profiler a bit and there is a lot of updating in thousands of small transactions...but I'm not sure what its doing...there's one update that runs thousands of times thats updating a long ntext column in table VPX_SDRS_STATS_VM but thats not the only thing happening. I've checked the vCenter agent jobs (that roll up data). They are working and they are not generating the transaction traffic.
So any ideas on what vCenter is doing? Any ideas on how to tone it down? Please no suggestions about tuning SQL Server...I'm pretty sure I've looked into everything on that side....we don't need advice on maintaining the transaction log...we can do that. The question is with the vCenter App. activity itself.
Thanks for your time