I was wondering if the extra layer of whatever filesystem the swap file is created on creates overhead? Also i think some filesystems that do COW can negatively impact performance or something? Kind of remember reading that.
For swap files on btrfs COW and features like compression have to be disabled. I believe for btrfs the swap file even has to sit on a subvolume with those features disabled, so it’s not enough to only disable them for the swap file.
I’ve never noticed an appreciable performance hit, but I also don’t generally swap much. Most of the time on a desktop/workstation I’m surprised to see a gig or 2 in swap. Nvme drives are pretty fast.
If you are actually using swap space on a regular basis it might be worth it to upgrade RAM or use a dedicated drive for swap if necessary.
I remember btrfs having swap file issues but the details are fuzzy, these days I use zfs on my nas and ext4 everywhere else.
I was wondering if the extra layer of whatever filesystem the swap file is created on creates overhead? Also i think some filesystems that do COW can negatively impact performance or something? Kind of remember reading that.
For swap files on btrfs COW and features like compression have to be disabled. I believe for btrfs the swap file even has to sit on a subvolume with those features disabled, so it’s not enough to only disable them for the swap file.
I’ve never noticed an appreciable performance hit, but I also don’t generally swap much. Most of the time on a desktop/workstation I’m surprised to see a gig or 2 in swap. Nvme drives are pretty fast. If you are actually using swap space on a regular basis it might be worth it to upgrade RAM or use a dedicated drive for swap if necessary. I remember btrfs having swap file issues but the details are fuzzy, these days I use zfs on my nas and ext4 everywhere else.