ReFS memory requirements

[fsr]

Hi,

I'm on the process of sizing a Veeam server, and i checked the system requirements, https://helpcenter.veeam.com/docs/backu ... ments.html , but then i found this Best Practices document https://www.veeambp.com/repository_serv ... tory_types that says:

ReFS: make sure your server has 1 GB RAM per 1 TB used on repository, add additional 8 GB for the Windows Server operating system.

Is that up-to-date information? Because i'm running the trial in a system with only 8 GB total RAM, with an ReFS filesystem, and it doesn't seems to require that amount of memory, and the link to the microsoft site on the "best practices" document doesn't says anything at all about RAM, and the Veeam System Requirements doesn't mentions ReFS. The test machine is running Windows Server 2019, and Veeam 9.4 update 4.

Also, when it says "1 GB RAM per 1 TB used on repository" it refers to the total size of the repository? If that's so, why does it depend on the total size, if the jobs aren't running all at the same time?

Regards

[Mgamerz]

The information about the filesystem has to be stored in memory. As you approach larger sizes you don't have to follow 1GB / TB, (like 200+). You will definitely see performance hits when doing synthetic fulls if you don't have enough ram, it was pretty bad on Server 2016 until microsoft updated their implementation of it on the backend. I would have a synthtetic full that would normally take 20 minute take over 30 hours.

[fsr]

Thanks mgamerz. Yes i had seen some threads with horror stories about that. I was thinking that maybe the best practices document was based on the memory use from that times, but better to be safe than sorry.
2019 has it's own issues. It does not shutdown the VMs gracefully on host shutdown or restart. There are threads about that from december last year on technet. Microsoft says that they will fix it on september Fortunately, i have it installed only on a test machine.

The test machine is running [...] Veeam 9.4 update 4.

Sorry, i meant Veeam 9.5 update 4. Typo.