Hello Neil, For the benchmarking purpose, I've configured array of ~30GB. stripe_cache_size is 1024 (so 1M). BTW, I'm using Windows copy (robocopy) utility to test perf and I believe block size it uses is 32kB. But since everything gets written thru VFS, I'm not sure how to change stripe_cache_size to get optimal performance with this setup... Thanks. On Mon, Apr 11, 2011 at 7:51 PM, NeilBrown <neilb@xxxxxxx> wrote: > On Mon, 11 Apr 2011 18:57:34 -0700 Linux Raid Study > <linuxraid.study@xxxxxxxxx> wrote: > >> If I use --assume-clean in mdadm, I see performance is 10-15% lower as >> compared to the case wherein this option is not specified. When I run >> without --assume_clean, I wait until mdadm prints "recovery_done" and >> then run IO benchmarks... >> >> Is perf drop expected? > > No. ÂAnd I cannot explain it.... unless the array is so tiny that it all fits > in the stripe cache (typically about 1Meg). > > There really should be no difference. > > NeilBrown > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
