As a side note, when we migrated the exact same pgsql 8.3 system from linux kernel 2.6 to 3.6,
we experienced an almost dramatic slowdown by 6 times.
Linux Kernel's were known to have issues around those dates, i recall.
We had to set synchronous_commit to off, this gave a huge boost ,
but this was no longer "apples" vs "apples".
On 04/04/2014 07:03, François Beausoleil wrote:
> Hi all!
>
> Does PG perform that much better on FreeBSD? I have some performance issues on a Ubuntu 12.04 which I'd like to
resolve.iowait varies a lot, between 5 and 50%. Does FreeBSD better schedule I/O, which could alleviate some of the
issues,or not at all? I have no experience administering FreeBSD, but I'm willing to learn if I'll get some performance
enhancementsout of the switch.
>
> Our workload is lots of data import, followed by many queries to summarize (daily and weekly reports). Our main table
isa wide table that represents Twitter and Facebook interactions. Most of our reports work on a week's worth of data
(tableis partitioned by week), and the tables are approximately 25 GB plus 5 GB of indices, per week. Of course, while
reportsare ongoing, we're also importing next week's data.
>
> The host is a dedicated hardware machine at online.fr: 128 GB RAM, 2 x 3TB disk in RAID 1 configuration.
>
> I started thinking of this after reading "PostgreSQL pain points" at https://lwn.net/Articles/591723/. In the
comments,bronson says FreeBSD does not exhibit the same problems (slow fsync, double buffering). On the list here, I've
readabout problems with certain kernel versions on Ubuntu.
>
> I'm not expecting anything magical, just some general guidelines and hints. Did anybody do the migration and was
happierafter?
>
> Thanks for any hints!
> François Beausoleil
>
> $ uname -a
> Linux munn.ca.seevibes.com 3.2.0-58-generic #88-Ubuntu SMP Tue Dec 3 17:37:58 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
>
> $ psql -U postgres -c "select version()"
> version
> -------------------------------------------------------------------------------------------------------------
> PostgreSQL 9.1.11 on x86_64-unknown-linux-gnu, compiled by gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3, 64-bit
>
> /proc/cpuinfo says: 8 CPUs, identified as "Intel(R) Xeon(R) CPU E5-2609 0 @ 2.40GHz"
>
--
Achilleas Mantzios
Head of IT DEV
IT DEPT
Dynacom Tankers Mgmt