cuimalo

Excellent response, thank you! My mistake and bad math. > with the current kernel in 7.0.0, the crc feature uses much more overhead than reflinks, That's interesting, perhaps the overhead for reflinks has changed.

Nope. It's a default. Note that the above is incorrect as it was really a change to XFS tools in 5.1.0.

> mkfs.xfs ... reflink=0 As in my initial post. > just to recover like 0.5% of capacity? This is 10 TB on a 10 disk array with 20TB disks. Yes. > I'm trying to understand why this is so important for you Unraid is an appliance, not a Linux distro. The point of an appliance is that it works as preconfigured, it should not be tampered with. I have simply and repeatedly asked confirmation that reflink=1 was an intentional design decision. If so disabling it may break functionality or future updates. Uptime = profit. Downtime = cost. > block cloning is a very nice feature ... make a quick backup of a vdisk ... and other uses. Running VMs on an array is not recommended by Unraid. 0.001% of users need this feature, but all will miss the disk space.

Thanks for your participation! Let's keep this as a bug until we get clarification.

Hey Unraid friends! I need your help. Please comment on the bug report so we can get this fixed.

Bug report opened.

I don't follow, what's going on? Mod removed unrelated bad attitude posts. Thanks for the work on SnapRAID and mergerFS.

This issue is WAY worse than I thought, 100GB of wasted space!! This is a brand new blank 18TB Exos X20, model ST18000NM003D. Formatted through Unassigned Devices, then from the CLI without reflink.

You could use MergerFS, I believe it does all this including symlink reworks.

Exactly! It's reserved metadata space for a feature unusable by Unraid. I respect the effort inherent in your response, this issue could affect the majority of users. I will set up a testing bed and get back to you. On ZFS: I'm hesitant to use it with Unraid as there are too many corner cases, though I may build out a "Perfect Media Server" in future.

Thanks for helping me chase this down. This is wasted filesystem overhead, they will not show with "du" or "ls". I've cited a source in my original post. I'm familiar with those XFS tools, how can they be applied here?

Thanks for your reply, I see you have the reflink "stolen" space. The missing space is subtracted from the "SIZE" column of your screen shot of your spinning drives. It's wasted file system overhead.

OK, so this is a known issue. Looks like reformatting is required to reclaim the space. I imagine Unraid is using the defaults. As there's no use case (that I'm aware of) for reflink/COW support this might be a bug.

Yes. I'm on stable 6.12.14, I can start a fresh install if you'd like a diagnostic. Does your "xfs_info /dev/mdXXp1" on your box show reflink=1?