Обсуждение: asynchronous commit feature
I'm testing the new asynch commit feature on various raid configurations and my early findings is that it reduces the impact of keeping wal and data on the same volume. I have 10 disks to play with, and am finding that it's faster to do a 10 drive raid 10 rather than 8 drive raid 10 + two drive wal. anybody curious about the results, feel free to drop a line. I think this will be a popular feature. merlin
On Thu, Aug 23, 2007 at 09:09:00AM -0400, Merlin Moncure wrote: > I'm testing the new asynch commit feature on various raid > configurations and my early findings is that it reduces the impact of > keeping wal and data on the same volume. I have 10 disks to play > with, and am finding that it's faster to do a 10 drive raid 10 rather > than 8 drive raid 10 + two drive wal. > > anybody curious about the results, feel free to drop a line. I think > this will be a popular feature. With or without a write cache on the RAID controller? I suspect that for many systems, a write-caching controller will be very similar in performance to async commit. -- Decibel!, aka Jim Nasby decibel@decibel.org EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Вложения
On 8/27/07, Decibel! <decibel@decibel.org> wrote: > On Thu, Aug 23, 2007 at 09:09:00AM -0400, Merlin Moncure wrote: > > I'm testing the new asynch commit feature on various raid > > configurations and my early findings is that it reduces the impact of > > keeping wal and data on the same volume. I have 10 disks to play > > with, and am finding that it's faster to do a 10 drive raid 10 rather > > than 8 drive raid 10 + two drive wal. > > > > anybody curious about the results, feel free to drop a line. I think > > this will be a popular feature. > > With or without a write cache on the RAID controller? I suspect that for > many systems, a write-caching controller will be very similar in > performance to async commit. I usually only work with mid to high end hardware. The platform I'm testing on is: 10x146gb 15k rpm sas in Dell md1000 2xperc 5/e in active/active (5 drives each controller) 2x146gb 15krpm sas on the backplane perc 5/i (for o/s, wal) in my experience, even with a high end raid controller moving the wal offline is helpful in high activity systems, especially during checkpoints. merlin