Be aware: Microsoft KB4507469 appears to introduce ReFS issues on Server 2019

[Stupots]

Hi, not strictly a Veeam product issue (so little point of raising a support case) but I have been trying to get our new Veeam Repository server online for a few days now. The issue we had was that when we tried to format the repository with ReFS it would fail with an "Unspecified Error". After much trouble shooting, representing the volume from our array and reformat attempts we found an issue that meant it would only format ReFS on or below 128TB. If we tried formatting it with 129TB it would fail. An NTFS Format was fine on any size.

Today I rebuilt the server with Server 2019 again and before installing any updates, tried the full 250TB ReFS format and it worked just fine. I then carried on building the server, including Windows Updates and then when I tried a reformat it would fail (but would still succeed on or smaller than 128TB). I then tried uninstalling update KB4507469 and I could once again do a ReFS format of any capacity.

Considering this will likely affect people using Veeam more than the average user, maybe Veeam could attempt to recreate this in a lab and if they are able to reproduce the issue, take this to Microsoft? For now, we will likely

Cheers

Stu

[Gostev]

Thanks, Stuart. I will let the ReFS development team at Microsoft know immediately.

[Gostev]

They have reproduced this internally and are actively investigating now.

[Mgamerz]

[Sticking with Server 2016 intensifies]

[Stupots]

Thanks @Gostev, that's great news! I did raise a case straight after posting this, it's case # 03691047

[PeterC]

What you can use as workaround (we bumped into this issue) is create a partition smaller then 128 TB, format it and that expand the volume to the desired size.
We are now using a 218 TB volume without any trouble.

[Stupots]

Thanks @PeterC, we did think about this, as well as formatting without the update installed and then re-installing it. This new repo will contain important production data and we are not confident that we wouldn't run into issues when more than 128TB is in use or a similar. For now we have rebuilt the server with 2016, as an upgrade or rebuild of a Veeam Proxy to 2019 is fairly trivial.