RE: [Bacula-users] Backups very SLOW

[Jamie f. <ja...@in...>]

Thanks for the feedback Alan.

Along those lines, I've just done something similar to help with the WAL's
on PGSQL.  Increased wal_buffers to 64, and put the pg_xlog directory on a
separate physical disk (WAL writes separate from the data files), and got
60KB/s improvement on backup rate, which is approx 8% faster.

This got virtually the same speed improvement as turning fsync off on an
identical backup run (slightly better than disabling fsync entirely), so I
can leave fsync on.

Jamie

> On the subject of PgSQL vs MySQL...
>
> This data is several years old now, but a colleague and I benchmarked
> MySQL vs Postgres while evaluating processes running several million
> inserts/reads and massive concurrency. (It was the forerunner of one of
> the most popular DNSBLs of the time.)
>
> The end results:
>
> MySQL is mostly faster in inserts because Postgres does a fsync() after
> every insert - safer, but slower than MySQL, which doesn't.
>
> MySQL is optimised for webserver use - results are best on repetitive,
> simple queries, it falls away rapidly on complex queries, lots of inserts
> or lots of parallel accesses - and especially when there are combinations
> of these (300+ processes accessing a MySQL server is _ugly_).
>
> Postgres' fsync() can be disabled and this makes it a _lot_ faster, at
> cost of risk of loss of data.
>
>
> I was quite surprised to read the claim that MySQL is optimised for
> inserts. This isn't my experience...
>
> This may all be well out of date. It's been about 4 years since I looked
> at the comparisons between these databases, but may serve as a pointer.
>
> Index creation slows inserts, but makes reads a _lot_ faster. As always
> it's a tradeoff about how often you're doing things, but if either
> database can now be loaded with inserts which are then committed this
> should speed up everything overall. That's the way the Oracle-engined
> replacement we were working on was designed before the project was
> abandoned.
>
> Have any database analysts looked at Bacula's DB setup?
>
> AB
>
>
>
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