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.
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.
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 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.
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.
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.