Veeam SQL and memory usage

[b.vanhaastrecht]

Hi,

I'm investigating an issue with SQL and memory usage on a Veeam B&R server. I got triggered by our monitoring software issued an warning for high pagefile usage on the B&R server. After investigating I found that SQL's memory was placed to the pagefile. The server has 10GB of memory which 7GB was used, so it had 3GB free to use. So why is SQL's being paged out.

Searching around on the net I've learned Windows will page out memory when it detects very low usage. The server is our main B&R with CC and a lot of jobs on it, memory usage stays on 7GB in physical, and does not change during running backup jobs. Also, the pagefile usage stays at the same level of about 70%. So during the backup you would expect SQL being more active so the pages would return to RAM, but that isn't the case, it stays at 70%.

Because our B&R is an VM, I do not like the IOPS from pagefile usage on disk while there's RAM available, and it's substantial.

Secondly, I've noticed Veeam does not set a memory limit on the SQL express instance. It's set to default "2147483647" MB, while with our lage scale setup the DB's are only at 250 and 300MB. It's best practice to set a limit not larger than the DB's. Perhaps this is the reason SQL is so low on active pages it gets paged out.

Any thoughts on this?

Regards,
Bastiaan

[PTide]

Hi,

Secondly, I've noticed Veeam does not set a memory limit on the SQL express instance<...>

There was a discussion on a similar topic, please see this thread.

Thank you.

[PTide]

If setting up a new memory limit does not solve paging problem then I have a very dirty hack...

In case your B&R server is a VM which is not used for anything but backups, then you could try setting up a RAM drive and place your pagefile there...

[b.vanhaastrecht]

Thats one way of doing it, thanks.

Found https://support.microsoft.com/en-us/kb/918483 which refers to Lock memory of a certain user account in RAM, this ensures SQL's memory is not paged out. But https://support.microsoft.com/en-us/kb/2659143 states it will not work on Express editions...

[PTide]

Hi,

Thank you for your reply!

I wanted to tell you about the Lock Memory feature, but then I thought that your blue nickname probably means that you are already aware

[vmJoe]

I believe that SQL Express is limited to only 1 CPU and 1 GB RAM per instance. If you need any kind of performance or in a larger installation it's always best to put the Veeam Backup and Replication DB on a standard version of SQL.

https://msdn.microsoft.com/library/cc645993.aspx

[adrianIDC]

I have observed that the MV where I have installed V B & R and ONE has a use of 95% ( mv has 4GB RAM) without work due to VEEAMSQL2012 process.

Can I limit the use of RAM to SQL2012 ( where installed veeam default )

[foggy]

Adrian, please review above for some hints.