Re: [gentoo-user] Advice/best practices for a new Gentoo installation

[Alex Schuster <wonko@wonkology.org>]

Alex Schuster writes:
> Neil Bothwick writes:
> > On Wed, 3 Mar 2010 12:52:55 +0100, Alex Schuster wrote:
> > > > The data I've seen indicates that ext2 is fastest, that's what I
> > > > use.
> > > 
> > > I thought the small files of the portage tree especially profit
> > > from the notail option in reiserfs?
> > 
> > They benefit compared with using reiser with tail-packing.
> 
> Oh my. I have it the other way around, and never even thought much
> about what this does.
> 
> > > Did you change the block size?
> > 
> > I had to change both the block size and blocks per inode, otherwise I
> > would run out of inodes on a 1GB filesystem. You have to admire the
> > user-friendliness of ext!
> 
> I only wished I could add more inodes after all are out, because this
> happens quite frequently to me. But yes, it's nice I can specify this
> at all.
> 
> > > > There's no need for journalling on the portage tree, it's small
> > > > enough to fsck quickly and if it does get broken, reformat and
> > > > resync.
> > > 
> > > Would the journaling overhead be noticeable?
> > > I also had used ext2 for my portage tree first, then I read
> > > somewhere that reiserfs would be the best. BTW, I have distfiles
> > > and pkgdir somewhere else, if not the fsck would not be so fast.
> > 
> > It's certainly noticeable compared with ext3. Many benchmarks do show
> > ext2 to be the fastest filesystem, probably because of the lack of
> > journalling overhead.
> 
> When I saw some, it was maybe 15% difference, and that probably due to
> writes I assume. The portage tree is written during sync only, and then
> I do not care about speed. But would accessing lots and lots of small
> files be slowed down by journaling?
> 
> > Like you, I have $DISTDIR and $PKGDIR elsewhere, those files really
> > should not be mixed in with the portage tree.
> > 
> > > Just for fun, I just copied my $PORTDIR into my tmpfs, emerge -DpN
> > > @system @world takes between 81 and 53 seconds. With reiserfs, I
> > > get 130 seconds first ($PORTDIR was unmounted first and mounted
> > > again to clear the caches), and 57 seconds in the second attempt.
> > > 
> > > I had expected that tmpfs would be even faster. I think I just keep
> > > it the way it is now.
> > 
> > The exact same thought occurred to me. With a local tree to sync
> > from, tmpfs seemed a good choice (you could sync it from
> > /etc/conf.d/local) but it seems like it is not worth bothering with.
> 
> I would need more memory for that, I'm not at amd64 yet. But I probably
> should migrate anyway, and get another 4GB of memory.
> 
> > I'll try a reiser3
> > filesystem without tail packing to see if it beats ext2.
> 
> I backed up my portage tree, re-created the reiserfs partition, and
> mounted without notail option. The same emerge command now takes about
> three minutes... no, on 2nd try it's five. Hmm... ah, clementine is
> indexing files. Why does it do this, I did not change files. Oh, and it
> has indexed all of my /data/mp3, while I only gave it four subfolders
> to index. Why does no audio player just accept my choices for what the
> collection is, and add other stuff?
> 
> The next test gives 93 seconds, that's nice.
> 
> 	Wonko
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