Greg Smith wrote: > Recently I've made a number of unsubstantiated claims that the deadline > scheduler on Linux does bad things compared to CFQ when running > real-world mixed I/O database tests. Unfortunately every time I do one > of these I end up unable to release the results due to client > confidentiality issues. However, I do keep an eye out for people who > run into the same issues in public benchmarks, and I just found one: > http://insights.oetiker.ch/linux/fsopbench/ That is interesting; particularly since I have made one quite different experience in which deadline outperformed CFQ by a factor of approximately 4. So I tried to look for differences, and I found two possible places: - My test case was read-only, our production system is read-mostly. - We did not have a RAID array, but a SAN box (with RAID inside). The "noop" scheduler performed about as well as "deadline". I wonder if the two differences above could explain the different result. Yours, Laurenz Albe -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
