On Tue, Aug 12, 2014 at 11:40 PM, Marc Joliet <mar...@gmx.de> wrote: > Hi list > > For the longest time I've had portage configured to use the sqlite metadata > cache backend as per an old HOWTO [0], however, I thought that it would be a > good idea to revisit that decision. > > Now apparently, this was supposed to speed up portage, although even that > depends. For instance, [0] says that the metadata_overlay backend is faster > on > fast storage; since all of portage is on an SSD, that ought to be the case for > me. However, [0] is pretty outdated, so I don't really know, and don't have > any > comparison. > > In addition to that, I don't explicitly make use of the sqlite metadata cache, > that is, I don't (consciously) use any software that accesses those DBs, > except > for eix (except for overlays, where one would need to run "emerge --regen" > first, which is *ssssslllllloooowwwww*), which can make use of them if > CACHE_METHOD is set appropriately; this speeds up eix-update considerably. > > Does anybody here have experience with this, or a recommendation? I tried > switching to the default cache method temporarily to see how things perform, > and "emerge @world -uDNva" slowed down by about 30 seconds, so preliminary > results point to sticking with sqlite (although it could at least partly be a > btrfs performance regression in Linux 3.15, since there have been several > reports of > those, and several fixes slated for 3.16). Anyway, I'm also unsure of > unintended > consequences, or other settings I might have to change, too. > > Also, does anybody have any performance data and/or experience on using btrfs > with compression in this context? > > [0] http://www.gentoo-wiki.info/TIP_speed_up_portage_with_sqlite > > Greetings, > -- > Marc Joliet > -- > "People who think they know everything really annoy those of us who know we > don't" - Bjarne Stroustrup
Having tried this feature, I'd advise against it. It takes long time to generate metadata after sync and not really that advantageous. Also eix has it's own issues in this mode.
