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action #106841
openTry using tmpfs on openqaworker1 to use RAM more efficiently
Start date:
2022-02-15
Due date:
% Done:
0%
Estimated time:
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Description
openqaworker1 has 256GiB of RAM and currently hosts 20 workers which use around ~2GiB of RAM for the VM (depending on the test) and let's say 1GiB for the worker code each.
That means only ~60GiB of RAM are "actively" used during test runs, the remaining ~200GiB might be used as caches or buffers.
By using the NVMe storage devices (1T + 380G) as swap, it would be possible to use a tmpfs on /var/lib/openqa
to host the various isos and HDD images.
That way the kernel decides which data is written to disk (i.e. swap) at all, instead of flushing all data to a persistent filesystem regularly (triggered by QEMU). This might noticably increase test performance.
Possible advantages¶
- Less wear on the SSDs -> increase of lifetime
- Better performance of tests
- Could possible increase worker count further
Risks¶
- Some downtime required
- Might not work as intended, or at all, so the change might have to be rolled back
- The cache is no longer persistent, so it would have to download necessary assets after each day. That shouldn't be much of an issue, but might be noticable.
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