-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
TL;DR: I'm growingly getting tired of #5426 [1].
Every time I shut down a domain, I have to endure _seconds_ of freezing
in every other VMs of the same LVM Thin pool just because I have discard
passdown enabled. A quickly wearing SSD is the last thing I want,
however.
Other than performance, this can also be a security issue. Notice how
any VM can reliably tell whenever other VMs in the same pool are being
destroyed.
The thin pool driver (dm-thin) is to blame.
Commit 34fbcf6257eb ("dm thin: range discard support") [2] sort of
remedied this, yet the core persistent-data framework still manages to
insist in deleting ranges only _one_ node at a time. Rebalancing the
large btree a thousand times isn't exactly one of the things you'd
expect to be done in no time.
Possible solutions would be:
- - Patch dm-thin. Now to implement this properly, dm-thin must first
slice the range, have it ref'd somewhere and then issue discards (so
that it can handle power disruptions).
- - Switch to reflinks. BTRFS has been around 10+ years, so I assume it's
stable enough?
[1] https://github.com/QubesOS/qubes-issues/issues/5426
[2] https://git.kernel.org/torvalds/c/34fbcf6257eb3f39a5b78a4f51b40f881b82033b
- --
Sincerely,
Jinoh Kang
-----BEGIN PGP SIGNATURE-----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=l94N
-----END PGP SIGNATURE-----
--
You received this message because you are subscribed to the Google Groups
"qubes-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/qubes-devel/510c54bf-d89c-0b8a-abde-e179c29aea96%40gmail.com.
