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 However, [0] is pretty outdated, so I don't really know, and don't have any |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