• Zenorbi@lemmy.world
    1·
    13 days ago

    I used to be this guy. We have huge amount of memory in our storage server. Why would we need swap? Well, once the system started killing programs I read up on swap and how the system handles its caches, especially ZFS ARC.

    Short version is that while the system can evict its caches syncronously, it can only async notify ZFS that it should also shrink its caches, but the out-of-memory killer will start killing before ZFS and its kernel counterpart can start to free up memory.

    A tiny bit of swap completely solved this, since swapping is sync for the kernel and the OOM killer will wait for it.

  • rem26_art@fedia.io
    1·
    13 days ago

    Building a PC in 2026 be like “I cant afford RAM, but I can use a whole TB hard disk I shucked from an old WD external as swap and maybe my PC will feel modern”

    • mexicancartel@lemmy.dbzer0.comEnglish
      1·
      14 hours ago

      If you(or your distro) use zram then the zram usage may also count as swap in resource monitors. For me this was the case when i saw swap usage where it is clearly not needed to swap. You can check it with swapon commands.

      Other reason is that more frequently accesed files may be cached to ram and less important stuff gets swapped. But if you notice swap being used while total ram usage including cached is much lower than total, then its probably zram(and it does (Edit:)not write to disk so dont worry about that)