On Fri, 4 Jun 2010, Stephen Thompson wrote:
>
>
> Correction:
> I didn't notice the 8k per unit settings at first with postgres 8.1.
> Should read:
> effective_cache_size = 786432 # 6Gb
Assuming this is linux, you need to tweak /etc/sysctl/limits.conf a
little:
postgres soft memlock unlimited
postgres hard memlock unlimited
@postgres hard memlock unlimited
@postgres soft memlock unlimited
bacula soft memlock unlimited
bacula hard memlock unlimited
@bacula soft memlock unlimited
@bacula hard memlock unlimited
postgres soft rss unlimited
postgres hard rss unlimited
Don't forget to build the indexes and run analyse/vacuum commands.
So far I'm finding Postgres is far more forgiving than MySQL and has far
fewer parts to tune...
>
>
> On 06/04/2010 10:58 AM, Stephen Thompson wrote:
> >
> >
> > Hello everyone,
> >
> > We recently attempted a mysql to postgresql migration for our bacula
> > 5.0.2 server. The data migration itself was successful, however we are
> > disappointly either getting the same or significantly worse performance
> > out of the postgres db.
> >
> > I was hoping that someone might have some insight into this.
> >
> > Here is some background:
> >
> > software:
> > centos 5.5 (64bit)
> > bacula 5.0.2 (64bit)
> > postgresql 8.1.21 (64bit)
> > (previously... mysql-5.0.77 (64bit) MyISAM)
> >
> > database:
> > select count(*) from File --> 1,439,626,558
> > du -sk /var/lib/pgsql/data --> 346,236,136 /var/lib/pgsql/data
> >
> > hardware:
> > 1Tb EXT3 external fibre-RAID storage
> > 8Gb RAM
> > 2Gb SWAP
> > 2 dual-core [AMD Opteron(tm) Processor 2220] CPUs
> >
> >
> > Some of the postgres tuning that I've attempted thus far (comments are
> > either default or alternatively settings I've tried without effect):
> >
> > #shared_buffers = 1000 # min 16 or max_connections*2, 8KB each
> > shared_buffers = 262144 # 2Gb
> > #work_mem = 1024 # min 64, size in KB
> > work_mem = 524288 # 512Mb
> > #maintenance_work_mem = 16384 # min 1024, size in KB
> > maintenance_work_mem = 2097152 # 2Gb
> > #checkpoint_segments = 3 # in logfile segments, min 1, 16MB each
> > checkpoint_segments = 16
> > #checkpoint_warning = 30 # in seconds, 0 is off
> > checkpoint_warning = 16
> > #effective_cache_size = 1000 # typically 8KB each
> > #effective_cache_size = 262144 # 256Mb
> > effective_cache_size = 6291456 # 6Gb
> > #random_page_cost = 4 # units are one sequential page fetch cost
> > random_page_cost = 2
> >
> > Now, as to what I'm 'seeing'. Building restore trees are on par with my
> > previous mysql db, but what I'm seeing as significantly worse are:
> >
> > mysql postgresql
> > Within Bat:
> > 1) Version Browser (large sample job) 3min 9min
> > 2) Restore Tree (average sample job) 40sec 25sec
> > 3) Restore Tree (large sample job) 10min 8.5min
> > 2) Jobs Run (1000 Records) 10sec 2min
> >
> > Within psql/mysql:
> > 1) select count(*) from File; 1sec 30min
> >
> > Catalog dump:
> > 1) mysqldump/pgdump 2hrs 3hrs
> >
> >
> > I get a win on building Restore trees, but everywhere else, it's
> > painfully slow. It makes the bat utility virtually unusable as an
> > interface. Why the win (albeit moderate) in some cases but terrible
> > responses in others?
> >
> > I admit that I am not familiar with postgres at all, but I tried to walk
> > through some of the postgres tuning documents, including the notes in
> > the bacula manual to arrive at the above settings. Also note that I've
> > tried several variants on the configuration above (including the
> > postgres defaults), don't have a detailed play by play of the results,
> > but the time results above seemed typical regardless of what settings I
> > tweaked.
> >
> > Any help would be greatly appreciated!
> > Stephen
>
>
>
--
The real metric of thumb drives: "Will it Survive a Tumble in the Wash?".
------------------------------------------------------------------------------
ThinkGeek and WIRED's GeekDad team up for the Ultimate
GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
lucky parental unit. See the prize list and enter to win:
http://p.sf.net/sfu/thinkgeek-promo
_______________________________________________
Bacula-users mailing list
Bacula-users AT lists.sourceforge DOT net
https://lists.sourceforge.net/lists/listinfo/bacula-users
|
