On 26/05/11 20:31, Grzegorz JaÅkiewicz wrote:
Would HT have any impact to the I/O performance (postgresql, and fs in general) ?.
There have been previous discussions on this list about HT on vs off (I can't recall what the consensus, if any about what the cause of any performance difference was). In our case HT off gave us much better results for what we think the typical number of clients will be - see attached (server learn-db1 is setup with trivial hardware raid and then software raided via md, learn-db2 has its raid all in hardware. We've ended up going with the latter setup).
Note that the highest tps on the graph is about 2100 - we got this upto just over 2300 by changing from ext4 to xfs in later tests, and managed to push the tps for 100 clients up a little by setting no read ahead (NORA) for the arrays.
Cheers Mark
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