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Cake day: July 7th, 2023

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  • yes, the system will likely use some swap if available even when there’s plenty of free RAM left:

    The casual reader1 may think that with a sufficient amount of memory, swap is unnecessary but this brings us to the second reason. A significant number of the pages referenced by a process early in its life may only be used for initialisation and then never used again. It is better to swap out those pages and create more disk buffers than leave them resident and unused.

    Src: https://www.kernel.org/doc/gorman/html/understand/understand014.html

    In my recently booted system with 32GB and half of that free (not even “available”), I can already see 10s of MB of swap used.

    As rule of thumb, it’s only a concern or indication that the system is/was starved of memory if a significant share of swap is in use. But even then, it might just be some cached pages hanging around because the kernel decided to keep instead of evicting them.


  • if my system touches SWAP at all, it’s run out of memory

    That’s a swap myth. Swap is not an emergency memory, it’s about creating a memory reclamation space on disk for anonymous pages (pages that are not file-backed) so that the OS can more efficiently use the main memory.

    The swapping algorithm does take into account the higher cost of putting pages in swap. Touching swap may just mean that a lot of system files are being cached, but that’s reclaimable space and it doesn’t mean the system is running out of memory.
















  • Eager Eagle@lemmy.worldtoSelfhosted@lemmy.worldBackup recommendations
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    4 months ago

    fwiw, I used Kopia for around a year, but eventually the backup got corrupted with a BLOB not found error and there was no way to fix it.

    similar to this issue, except that nothing would fix or improve the situation https://github.com/kopia/kopia/issues/1087

    and because it seemed to be an issue with the repo (not just with a snapshot), the remote copy was also borked. I couldn’t even list the snapshots.

    I’ve since migrated to Rustic (though Restic might be more reliable today).

    This seems to be the a similar issue too, but I was nowhere near the scale of this user. There are other similar reports that may or may not be linked to the same root cause, so it’s hard to say how rare this problem is.