Updated: Microsoft launch patch to fix ReFS issues < ProVirtualzone

Finally, Microsoft launch patch to fix ReFS issues KB4077525. This patch will fix some of the issues that users were getting while using ReFS. Mainly when using significant Volumes and big files like in backups (particularly if ReFS is formatted with 64K, but we can find memory issues when the is formatted with 4K)

ReFS issues is a subject that is on the agenda particularly for Backup companies, like Veeam. Veeam support has been working a lot with ReFS development team at Microsoft regarding this issue.

Some of the issues that we could encounter when using ReFS were:

Heavy memory use in the Resilient File System (ReFS) file system type on a computer that is running Windows Server 2016.
ReFS volume become unresponsive or freeze when you perform backups. This can specifically occur when you use a backup application that does large block-clone operations.
Performance issues in Backups operations
Issues when ReFS is formatted with 4K Block Size (The recommendation for Veeam Backup Repositories is 64K Block Size ).

Fixes addressed in this Patch:

Improves ReFS performance by more thoroughly unmapping multiple views of a file. See KB4090104 for additional tunable registry parameters to address large ReFS metadata streams.
Improves ReFS performance by removing idle containers from its hash table.

Note: If you are running a pre-release driver from Microsoft support, it needs to uninstall before you install this patch. This is mandatory.

For now, we all hope all those ReFS issues are fixed when we are handling significant volumes. Particularly in backups.

Since now this issue is fixed, next I will write an article how to evacuate and move your NTFS Veeam Backup Repository to a ReFS Repository. Plan to write this in the next days.

UPDATE 06/03/2018: It seems that after I publish this blog post, Microsoft removed the patch from Windows Server 2016 from the Microsoft Update Catalog. Now is only available for Windows 10. Patch add an issue when applying in Domain Controllers ADFS database corruption bug. But it seems is nothing related to ReFS.

If you had the change to download this patch before it was removed, do not apply in any Domain Controller. If you did not download the patch before was removed, you need to wait until is re-released and uploaded to Microsoft Update Catalog.

The patch can still be applied in Windows 10 without any issues.

UPDATE 13/03/2018: Microsoft launched in this date a new update KB4088787 about this issue and in the Microsoft Update Catalog is again available the fix for Windows 2016.

The issue with AD FS server is fixed in this new update, so the previous patch to fix ReFS is already included for Windows 2016.

ReFS is still a working issues. Microsoft is still improving this format and trying to fix some of the issues that users are still encounter. But the main issues with the memory are fix it, so for most of the users they should see improvements using ReFS.

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