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Re: Maildir vs. mbox in Debian

On Thu, Nov 29, 2012 at 04:32:33PM +0100, Vincent Lefevre wrote:
> On 2012-11-29 16:16:25 +0100, Adam Borowski wrote:
> > *cough* btrfs -ocompress=lzo.  Small files are packed inline in metadata
> > blocks, and you get compression you wanted.  Using lzo is faster than no
> > compression for most loads, adding negligible cost for incompressible data
> > (especially if not all cores are at 100% usage).
> Great! Nice to know.
> This should be the default in Debian. :)

Not while dpkg calls fsync() every, approximately, 0.1 bits written.
Btrfs has transactions one could use to wrap around a whole dpkg operation,
avoiding fsync entirely -- at the cost of having filesystem specific code.

But for now you can even think of btrfs only if either you're on stable and
don't mind upgrades taking forever, or you use eatmydata.  The latter is
actually safe if you use btrfs snapshots and revert if power fails during
a dpkg run, but sadly, it currently requires quite a bit of manual work,
especially to build an appropriate filesystem layout.

A machine that's primarily a mail server could use btrfs for the filesystem
that holds the mail, of course.

Outside of dpkg, sqlite in non-WAL mode, other databases and virtualbox/
qemu, btrfs is pretty fast.

How to squander your resources: those silly Swedes have a sauce named
"hovmästarsås", the best thing ever to put on cheese, yet they waste it
solely on mere salmon.

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