On Sun, 8 Aug 2010 16:09:24 +0200, Ralf Hildebrandt <Ralf.Hildebrandt@xxxxxxxxxx> wrote: > * Marcus Kool <marcus.kool@xxxxxxxxxxxxxxx>: >> >> Nyamul Hassan wrote: >> >Hi, >> > >> >I would build with the following in mind: >> > >> >1. Better to have a separate disk for the cache stores. >> >2. Have a COSS store for objects less than 256k. And let AUFS handle >> >larger objects. >> >3. Don't have more than 75% of your disk allocated. >> >4. Only one AUFS store per disk. But you can have more than one COSS. >> >> Use AUFS on Linux and DISKD on BSD. > > Is this documented somewhere? I've been using diskd on ext4 on linux for > years now. Only in our upstream recommendations. It's due to a bug in the AIO implementation that only seems to show up in BSD derived systems. AUFS makes use of AIO threading support and should be great for BSD as well. Adrian foudn in his research that it has a scheduling/blocking problem in the Squid usage. It shows up on BSD derived systems but not Linux and slows AUFS down to speeds slower than diskd. So until somebody gets interested enough to fix that BSD is stuck on the older diskd as its fastest IO method. Amos
