this post was submitted on 20 Jul 2023
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What filesystem is currently best for a single nvme drive with regard to performance read/write as well as stability/no file loss? ext4 seems very old, btrfs is used by RHEL, ZFS seems to be quite good... what do people tend to use nowadays? What is an arch users go-to filesystem?

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[–] [email protected] 2 points 1 year ago (1 children)
[–] [email protected] 1 points 1 year ago (1 children)

First of all, thanks this r news for me. But I don't think is a good idea to use the swap file in btrfs.

It is supported since kernel 5.0

There are some limitations of the implementation in BTRFS and Linux swap subsystem:

filesystem - must be only single device

filesystem - must have only single data profile

subvolume - cannot be snapshotted if it contains any active swapfiles

swapfile - must be preallocated (i.e. no holes)

swapfile - must be NODATACOW (i.e. also NODATASUM, no compression)

With active swapfiles, the following whole-filesystem operations will skip swapfile extents or may fail:

balance - block groups with extents of any active swapfiles are skipped and reported, the rest will be processed normally

resize grow - unaffected

resize shrink - works as long as the extents of any active swapfiles are outside of the shrunk range

device add - if the new devices do not interfere with any already active swapfiles this operation will work, though no new swapfile can be activated afterwards

device delete - if the device has been added as above, it can be also deleted

device replace - ditto
[–] [email protected] 1 points 1 year ago

Yes, there are some limitations to be aware of, with how it interacts with certain features. But EXT4 doesn't have any of those features at all. It doesn't have CoW, or balance, or multi-device, or snapshots.

If the filesystem, is single-device, and you have the swapfile on it's own nocow subvolume, preallocate the swapfile, and don't try to take snapshots of it, it should be fine.