Raleigh wrote:Are you saying that increasing the amount of RAM in our ReFS repository server can improve its reliability (preventing the server crashes we're experiencing when large .vbk files are deleted)?
Yes, that is exactly what I'm saying. ReFS definitely uses more memory than NTFS, especially kernel memory, and deletes of large files with lots of referenced blocks are one of the big hitters for spikes in memory usage. When deletes of large files with many reference blocks occur on ReFS, you may not see a ton of memory usage from an application perspective, but kernel memory will definitely increase, and, if it gets tight, can lead to deadlocks. I believe this is still a bug in the Windows 2016 memory management code, but having lots more free RAM helps to mitigate it (it does not completely eliminate it). Based on that, I definitely don't recommend running ReFS with anything less than the best practice memory configuration. If Microsoft ever corrects this issue (it's been hinted to me that the fix is in the RS4 builds), then perhaps this concern will go away. Exactly how much memory you will need is difficult to say, but certainly more than the absolute minimum, which is what I would consider you to have.
Raleigh wrote:I've had several open tickets with Veeam Support on our issue, and never did they bring up the amount of RAM in the server. Also, I worked with a Veeam sales team (sales guy and his technical sidekick), and they vetted the server configuration before I even placed the order with Dell. If it is a known fact that increasing the RAM could resolve this type of problem, I'm willing to give it a try. I wish I would have known about this sooner.
Also, I realized I left out the CPU info for our server. It has dual Xeon Silver 4108 CPUs, with 8 cores each, for a total of 16 cores. Based on your recommendation, 64GB of RAM is a best practice for our Veeam repository server with 16 CPU cores. Correct?
I'm quite disappointed that the SE didn't provide some additional guidelines based on our best practice, however, we do have a lot of SEs these days, so they could have been new themselves. You can read the sizing recommendations for repos for yourself here:https://bp.veeam.expert/architecture-ov ... ing/sizing
Note that the best practice guide is maintained by the Solutions Architecture team here at Veeam and thus it reflects not the minimums, but the recommendations that we've collected based on significant field experience with customers small and large. I am part of that team (specifically the Principal Solutions Architect for NA). Our goal in maintaining the best practice guide is to document guidelines that will provide the best performance and reliability across a wide range of circumstances using proven practices from the field.
Raleigh wrote:Can anyone confirm that adding RAM to their repository server resolved (or greatly minimized) this "ReFS-related server crash" issue? I'm willing to throw money at this problem, but I'd like to know it's not wasted money.
There's a post on the last page that is a reply to your message that specifically says exactly this, perhaps you didn't see it?veeam-backup-replication-f2/refs-4k-horror-story-t40629-1035.html#p285642