Re: [gentoo-user] Re: /var/tmp/portage on tmpfs

[Rich Freeman]

On Wed, Jan 7, 2015 at 3:17 PM, Neil Bothwick <neil@××××××××××.uk> wrote:
> On Wed, 7 Jan 2015 14:25:52 -0500, Rich Freeman wrote:
>
>> > Not as a general FS, but as a specific choice for $PORTAGE_TMPDIR it
>> > may be worth testing. XFS was designed for an environment that used
>> > temporary files that didn't need to be committed to disk, so its
>> > caching doesn't write to disk anywhere near as often. That means you
>> > would be working with files stored in RAM a lot of the time.
>> >
>>
>> If you're going to be saving the build files using mv/ln (or with cp
>> --reflink on a filesystem that supports this), then the LAST thing I
>> would do is use a different fs for PORTAGE_TMPDIR.  The
>> best-performing option would be to make it a directory on the same
>> filesystem as wherever you're going to store the files by
>> moving/(ref)linking them.  That makes the move/(ref)link operation
>> require minimal IO.
>
> That's not what I meant, but I see your point about using --reflink if
> making copies. My thought was to forget the whole tmpfs and copying
> think, set KEEP WORK in FEATURES and use XFS for PORTAGE_TMPDIR. That way
> most of the work is taking place in the cache without the frequent disk
> writes of other filesystems. I would expect XFS to be faster for this
> job, but have no data to support that assumption.
>
> Or you could just put TMPDIR on btrfs and snapshot after each emerge.
>

If you're not going to move it but just leave it all in TMPDIR
forever, then by all means use whatever filesystem you like.  Sure,
you could snapshot it and clean it, but that might not be the cleanest
way.

-- 
Rich