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Does anyone have any idea why Cachy is so hard on I/O? If I run it with disk encryption my entire system hangs intermittently when downloading large files. (eg

Does anyone have any idea why Cachy is so hard on I/O? If I run it with disk encryption my entire system hangs intermittently when downloading large files. (eg steam updates, etc.) Even testing without disk encryption, I will get brief hangs when writing large files. Is Cachy just assuming that everyone's got a high-quality NVME? Is there something about newer OSes that cause a CPU bottleneck for large disk writes?

Bender 3mo ago
Which filesystem do you have on top of the encryption? If it's the default btrfs that might be one factor. Have you tested using ext4? What is the make/model of the physical storage?
- everdrive 3mo ago
  I tried it with BTRFS and had really terrible performance. I ended up trying ext4 and it was not appreciably better. I don't know the make and model of my SSD, but I'm sure it's a not-very-impressive SSD. Unencrypted with EXT4 was the only thing that offered good performance. Mind you, I'm really happy with CachyOS, but I don't really understand why this is a problem and it doesn't seem to be an issue others are having.
  - Bender 3mo ago
    Maybe this is something you have already checked but first get your device with blkid or whatever you prefer, then sudo smartctl -x /dev/nvmeXXXX Look at the temperature when you are pushing the IO really hard. Some devices will throttle when hot. Is this on a laptop? Do you have any indoor pets that have fur? Yaks shed a lot this time of year.
    - everdrive 3mo ago
      I'll check that out. In my case I had moved straight from Fedora and was using LUKS + EXT4 -- with no issues whatsoever. Further, rather than losing some write speed, my system will actually hang quite aggressively. It seems to be CPU-related, but perhaps it's disk reads that are hanging? (or maybe both) My PC case is also not extra-hairy :)
      - Bender 3mo ago
        To benchmark the encryption if you suspect CPU related, try cryptsetup benchmark though it's more useful if it was run prior on your previous OS installation. For storage, fio [1] may be useful but that is a much more involved topic and having baseline tests run in your former OS that you said worked fine. [1] - https://fio.readthedocs.io/en/latest/fio_doc.html https://fio.readthedocs.io/en/latest/fio_doc.html

Bender 3mo ago

Which filesystem do you have on top of the encryption? If it's the default btrfs that might be one factor. Have you tested using ext4? What is the make/model of the physical storage?

everdrive 3mo ago
I tried it with BTRFS and had really terrible performance. I ended up trying ext4 and it was not appreciably better. I don't know the make and model of my SSD, but I'm sure it's a not-very-impressive SSD. Unencrypted with EXT4 was the only thing that offered good performance. Mind you, I'm really happy with CachyOS, but I don't really understand why this is a problem and it doesn't seem to be an issue others are having.
- Bender 3mo ago
  Maybe this is something you have already checked but first get your device with blkid or whatever you prefer, then sudo smartctl -x /dev/nvmeXXXX Look at the temperature when you are pushing the IO really hard. Some devices will throttle when hot. Is this on a laptop? Do you have any indoor pets that have fur? Yaks shed a lot this time of year.
  - everdrive 3mo ago
    I'll check that out. In my case I had moved straight from Fedora and was using LUKS + EXT4 -- with no issues whatsoever. Further, rather than losing some write speed, my system will actually hang quite aggressively. It seems to be CPU-related, but perhaps it's disk reads that are hanging? (or maybe both) My PC case is also not extra-hairy :)
    - Bender 3mo ago
      To benchmark the encryption if you suspect CPU related, try cryptsetup benchmark though it's more useful if it was run prior on your previous OS installation. For storage, fio [1] may be useful but that is a much more involved topic and having baseline tests run in your former OS that you said worked fine. [1] - https://fio.readthedocs.io/en/latest/fio_doc.html https://fio.readthedocs.io/en/latest/fio_doc.html