Proceed with fingers crossed!
From my experience with Veeam and ReFS the main problem, which poped up already for several years with Windows Server 2019, was the delete of lage files (several TB). It often happens, that after you or veeam has deleted a huge file, the space is not free, but somehow lost. Not occupied by any files, not in the recycle bin, just not available. On server 2019 it has been typically the size of the files above 4TB (64kB Block size) - so a 6 TB file produced 2TB loss - and I found no way to gain it back but reformat the drive. On Server 2025 it's even worse. after in our case e.g. 16 hours after deleting if we do it manually nothing happens, but space ist lost. Otherwise when veeam is starting the job you don't have this time gap. Nevertheless at some point veeam using the volume triggers ReFS to do something and it ends with a totally blocked computer after a few hours. I'm not familiar with the ReFS details regarding deleting files, but from my experience with HPFS and NTFS it should be doable. But since ReFS is somehow transactional even whe deleting files, therr must be a loop(hole) or something built in and all the occupation of the to be deleted files on the volume is first moved to another directory place to be save on completing of the transactions and then in a second step these "new" direcory entries are removed and the space is marked free in the free space bitmaps. shouldn't be an unsolvable problem, but Microsoft ....
Just my thought on that
Jo
From my experience with Veeam and ReFS the main problem, which poped up already for several years with Windows Server 2019, was the delete of lage files (several TB). It often happens, that after you or veeam has deleted a huge file, the space is not free, but somehow lost. Not occupied by any files, not in the recycle bin, just not available. On server 2019 it has been typically the size of the files above 4TB (64kB Block size) - so a 6 TB file produced 2TB loss - and I found no way to gain it back but reformat the drive. On Server 2025 it's even worse. after in our case e.g. 16 hours after deleting if we do it manually nothing happens, but space ist lost. Otherwise when veeam is starting the job you don't have this time gap. Nevertheless at some point veeam using the volume triggers ReFS to do something and it ends with a totally blocked computer after a few hours. I'm not familiar with the ReFS details regarding deleting files, but from my experience with HPFS and NTFS it should be doable. But since ReFS is somehow transactional even whe deleting files, therr must be a loop(hole) or something built in and all the occupation of the to be deleted files on the volume is first moved to another directory place to be save on completing of the transactions and then in a second step these "new" direcory entries are removed and the space is marked free in the free space bitmaps. shouldn't be an unsolvable problem, but Microsoft ....
Just my thought on that
Jo
Statistics: Posted by jokoenen — May 23, 2025 4:16 pm
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