At 01:26 PM 2/20/2015 +1300, Robin Sheat wrote:
Chad Roseburg schreef op do 19-02-2015 om 15:14 [-0800]:
> We are considering mounting the index files to a separate high-performance
> disk array in hopes of improving performance during the indexing process --
> has anyone experimented with something like this?
It'd be worth seeing where the slowdown in the indexing actually is: is
the exporting the slow part, or the merging into the index?
Though, I've never tried with zebra indicies on a high speed disk, I'd
be interested to see some real benchmarks.
Not absolute, but... our latest server uses SSD (raided 240 Gig Kingstons)
rather than HDD (raided 500 Gig Seagates) with very slightly faster 8-core
CPU, same 18 Gigs RAM; and the "read speed" (counting by 100's) of a total
re-index is about twice as fast, with authorities faster than biblios.
However, the "Cleaning" stage is disappointingly about the same speed,
maybe a tad faster but barely perceptible. Memcached enabled on both boxes,
same version of Zebra. I get the *impression* that Zebra sorts (or does
some other process) during the final write stage, otherwise we'd have seen
an improvement.
However, we rarely use the full re-index, having got the Cron job fully
sorted every minute (including minor tweaking of
biblio-zebra-indexdefs.xsl) -- and that is as near instantaneous as anyone
could wish.
Best -- Paul
Also, more RAM might be
useful for disk caching, and you could experiment with disk fsync()
commit options (i.e. by making it not require data to be written back
before returning.) This has risk though, but if you're careful, it could
well be acceptable, for example just needing to a full reindex in case
of a power outage.
--
Robin Sheat
Catalyst IT Ltd.
â +64 4 803 2204
GPG: 5FA7 4B49 1E4D CAA4 4C38 8505 77F5 B724 F871 3BDF
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