Hi, At Mon, 21 Sep 2009 16:54:50 +0300, Saloustros Georgios wrote:
> Software Raid-0 consists of two Maxtor 500 GB with chuck size 64K. > System's Memory is 2GB. > For testing reasons I wrote a simple disk benchmark in java, where 8 threads > append 256KB dummy blocks from memory to a log-file. Total IO is 8 GB. > With ext3 mounted with data=writeback mode, each drive alone gives 63MB/sec > and as a raid-0 array a total of 90 MB/sec. > > Nilfs has worst performance for the same scenario. 1 Disk alone gives 34MB/sec > and two disks on raid-0 setup 39 MB/sec. > > Using iostat I can see that disks are 50% utilized with nilfs, whereas with > ext3 are 100% utilized. Why is this happening? Is my configuration wrong? I'm not sure about the utilization but, the performance may be degraded by the nilfs GC process. As far as I see with my benchmark, result is twice better when stopping the GC process intentionally. So if that's your case, performance will be expected as 38MB/sec for 1 disk and 78MB/sec for raid-0. Or you may tune your GC process by editing /etc/nilfs_cleanerd.conf, decreasing nsegments_per_clean, increasing cleaning_interval. Then GC process will affect the results less than it does. Still, there is more room to improve write performance of nilfs2, I think :). thanks regards, -- Jiro SEKIBA <[email protected]> _______________________________________________ users mailing list [email protected] https://www.nilfs.org/mailman/listinfo/users
