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Re: RFC: Support for zstd in .deb packages?




On Fri, Apr 27, 2018 at 09:44:09AM +0200, Martin Steigerwald wrote:
> Regarding technical aspects like these, one more data point: BTRFS 
> meanwhile offers zstandard compression support. So I bet BTRFS 
> developers consider it suitable for format stability and long-term data 
> storage. I am still using lzo on my BTRFS filesystems, so I can not tell 
> any practical experiences so far.

I've been using zstd on btrfs since half a year before it was mainlined:
there wasn't a single problem that would threaten stability; usual
development woes (alloc/dealloc thrashing, etc) were fixed long before
patches went to -next.

It compresses better than gzip while being faster than lzo, thus there is no
reason to use either if you won't ever use kernels < 4.14 (and, if you ever
compressed a single file with zstd, the incompat flag is set, so you can't
even mount with old kernels anyway).

There is one remaining problem: patch adding zstd support to grub is still
not merged (same as f2fs support, etc...).  This is not a problem for
vmlinuz or initrd (these are compressed already and btrfs backs off from
compressed files very cowardly), but /boot/grub/grub.cfg usually _does_ get
compressed thus you need to prop it off:

find /boot/grub -exec btrfs prop set '{}' compression zlib \;
(properties on newly created files will get copied from parent dir, need to
manually set existing ones)

And yeah, we probably should molest grub's maintainer in Debian...


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