Zygo

Followup question 2: how long does btrfs ins log 0x13d70b21000 /path/to/your/fs take to run (without running bees)? What is the size of the .vdi file?

> The 'btrfs ins log...' test I can provide next week. This might not reveal anything after the snapshot is deleted; however, just fixing the problem by deleting the snapshot...

We really need those kernel stacks: ps xar | while read -r x y; do ps "$x"; head -50 --verbose /proc/"$x"/task/*/stack; done | tee lockup-stacks.txt The pstree output is typical...

The important problem here is that btrfs currently does not provide **any** reliable safe path to move from 2-disk raid1 to single-disk filesystem with dup metadata. The requirements are: Starting...

> While having active access times does slow any fs this discussion is giving the impression btrfs has a significant problem with access time updates. _This impression is not wrong._...

> I'm sure only the metadata of the active snapshot should be affected by atimes That's true, but I'm not sure you fully understand the implications. The metadata of an...

Here is my developer box: filesystem is on a RAID1 pair of Seagate Ironwolf and WD Red SATA SSD, both rated for NAS usage. It has been mounted with `noatime`...

##### Update (and corrections to predictions) After 3 hours there were 122 GiB of metadata, and the `find -type f -ls` had finished running. I started running `find -type f...

> while having also an exceptional number of snapshots LOL, 100 snapshots is far from exceptional. > on a volume that was always mounted with a non-default policy to optimise...

I don't think the SSD performance is very relevant to stalls here, as I've observed similar numbers on a range of faster hardware. I didn't observe any unusually long IO...