On Tue, Dec 11, 2012 at 6:03 PM, Craig Ringer <craig@xxxxxxxxxxxxxxx> wrote: > On 12/12/2012 06:44 AM, Evgeny Shishkin wrote: > > > On Dec 12, 2012, at 2:41 AM, Niels Kristian Schjødt > <nielskristian@xxxxxxxxxxxxx> wrote: > > Are you using a hardware based raid controller with them? > > Yes, of course. Hardware raid with cache and bbu is a must. You can't get > fast fsync without it. > > > Most SSDs should offer fairly fast fsync without a hardware RAID controller, > as they do write-back caching. The trick is to find ones that do write-back > caching safely, so you don't get severe data corruption on power-loss. > > A HW RAID controller is an absolute must for rotating magnetic media, > though. > > > Also mdadm is a pain in the ass and is suitable only on amazon and other > cloud shit. > > > I've personally been pretty happy with mdadm. I find the array portability > it offers very useful, so I don't need to buy a second RAID controller just > in case my main controller dies and I need a compatible one to get the array > running again. If you don't need a BBU for safe write-back caching then > mdadm has advantages over hardware RAID. > > I'll certainly use mdadm over onboard fakeraid solutions or low-end hardware > RAID controllers. I suspect a mid- to high end HW RAID unit will generally > win. Also for sequential throughput md RAID is usually faster than most RAID controllers, even the high end Areca and LSI ones. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
