Marko Milisavljevic wrote:
I missed an important conclusion from j's data, and that is that single disk raw access gives him 56MB/s, and RAID 0 array gives him 961/46=21MB/s per disk, which comes in at 38% of potential performance. That is in the ballpark of getting 45% of potential performance, as I am seeing with my puny setup of single or dual drives. Of course, I don't expect a complex file system to match raw disk dd performance, but it doesn't compare favourably to common file systems like UFS or ext3, so the question remains, is ZFS overhead normally this big? That would mean that one needs to have at least 4-5 way stripe to generate enough data to saturate gigabit ethernet, compared to 2-3 way stripe on a "lesser" filesystem, a possibly important consideration in SOHO situation.
Could you post iostat data for these runs? Also, as I suggested previously, try with checksum off. AthlonXP doesn't have a reputation as a speed deamon. BTW, for 7,200 rpm drives, which are typical in desktops, 56 MBytes/s isn't bad. The media speed will range from perhaps [30-40]-[60-75] MBytes/s judging from a quick scan of disk vendor datasheets. In other words, it would not surprise me to see 4-5 way stripe being required to keep a GbE saturated. -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
