On Fri, Jun 7, 2013 at 5:51 AM, Joshua D. Drake <jd@xxxxxxxxxxxxxxxxx> wrote: > > On 06/06/2013 03:48 PM, Scott Marlowe wrote: >> >> >> On Thu, Jun 6, 2013 at 4:35 PM, Joshua D. Drake <jd@xxxxxxxxxxxxxxxxx> >> wrote: >>> >>> I had the distinct displeasure of staying up entirely too late with a >>> customer this week because they upgraded to 12.04 and immediately >>> experienced a huge performance regression. In the process they also >>> upgraded >>> to PostgreSQL 9.1 from 8.4. There were a lot of knobs to >>> change/fix/modify >>> because of this. However, nothing I did fixed the problem. Until... I >>> upgraded the kernel. >>> >>> Upgrading from 3.2Precise to the 3.9.4 kernel produced the following >>> results: >> >> >> I've since heard that 3.4 also fixes this issue as well. >> >> What are you using for your IO on these boxes? > > I was able to demonstrate it over iSCSI to a Nimble Storage SAN as well as > DAS with 2 drive RAID 1 for xlogs and 8 drive RAID 10 for data (DL385 G7). This might sound familiar: http://postgresql.1045698.n5.nabble.com/Ubuntu-12-04-3-2-Kernel-Bad-for-PostgreSQL-Performance-td5735284.html tl;dr for that thread seems to be a driver problem (fusionIO?), I'm unsure if Ubuntu specific or in the upstream kernel. -- Stuart Bishop <stuart@xxxxxxxxxxxxxxxx> http://www.stuartbishop.net/ -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
