On Mon, Mar 4, 2013 at 4:17 PM, John Rouillard <rouilj@xxxxxxxxxxx> wrote: > On Mon, Mar 04, 2013 at 03:54:40PM -0700, Steven Crandell wrote: >> Here's our hardware break down. >> >> The logvg on the new hardware is 30MB/s slower (170 MB/s vs 200 MB/s ) >> than the logvg on the older hardware which was an immediately interesting >> difference but we have yet to be able to create a test scenario that >> successfully implicates this slower log speed in our problems. That is >> something we are actively working on. >> >> >> Old server hardware: >> Manufacturer: Dell Inc. >> Product Name: PowerEdge R810 >> 4x Intel(R) Xeon(R) CPU E7540 @ 2.00GHz >> 32x16384 MB 1066 MHz DDR3 >> Controller 0: PERC H700 - 2 disk RAID-1 278.88 GB rootvg >> Controller 1: PERC H800 - 18 disk RAID-6 2,178.00 GB datavg, 4 >> drive RAID-10 272.25 GB logvg, 2 hot spare >> 2x 278.88 GB 15K SAS on controller 0 >> 24x 136.13 GB 15K SAS on controller 1 >> >> New server hardware: >> Manufacturer: Dell Inc. >> Product Name: PowerEdge R820 >> 4x Intel(R) Xeon(R) CPU E5-4620 0 @ 2.20GHz >> 32x32 GB 1333 MHz DDR3 >> Controller 0: PERC H710P - 4 disk RAID-6 557.75 GB rootvg >> Controller 1: PERC H810 - 20 disk RAID-60 4,462.00 GB datavg, 2 >> disk RAID-1 278.88 GB logvg, 2 hot spare >> 28x278.88 GB 15K SAS drives total. > > Hmm, you went from a striped (raid 1/0) log volume on the old hardware > to a non-striped (raid 1) volume on the new hardware. That could > explain the speed drop. Are the disks the same speed for the two > systems? Yeah that's a terrible tradeoff there. Just throw 4 disks in a RAID-10 instead of RAID-60. With 4 disks you'll get the same storage and much better performance from RAID-10. Also consider using larger drives and a RAID-10 for your big drive array. RAID-6 or RAID-60 is notoriously slow for databases, especially for random access. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
