Messages in this thread | | | Date | Thu, 11 Mar 2004 17:12:35 -0500 | From | Bill Davidsen <> | Subject | Re: lvm2 performance data with linux-2.6 |
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markw@osdl.org wrote: > I've started collecting various data (including oprofile) using our > DBT-2 (OLTP) workload with lvm2 on linux 2.6.2 and 2.6.3 on ia32 and > ia64 platforms: > http://developer.osdl.org/markw/lvm2/ > > So far I've only varied the stripe width with lvm, from 8 KB to 512 KB, > for PostgreSQL that is using 8 KB sized blocks with ext2. It appears > that a stripe width of 16 KB through 128KB on the ia64 system gives the > best throughput for the DBT-2 workload on a volume that should be doing > mostly sequential writes. > > I'm going to run through more tests varying the block size that > PostgreSQL uses, but I wanted to share what I had so far in case there > were other suggestions or recommendations. > Here's one thought: look at the i/o rates on individual drives using each stripe size. You *might* see that one size does far fewer seeks than others, which is a secondary thing to optimize after throughput IMHO.
If you don't have a tool for this I can send you the latest diorate which does stuff like this, io rate perdrive or per partition, something I occasionally find revealing.
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