Hi, Mike On Tue, Oct 19, 2004 at 04:18:12PM -0400, Mike Jakubik wrote: > Xin LI said: > > > Unfortunatelly I can reproduce similiar problem when using Ultra320 under > > mpt(4) and a version of Adaptec's SCSI card (maybe aic, or something else, > > which I have to go to my office to find out). Additionally the problem is > > not FreeBSD specific, with a Linux installation, it shows poor performance > > too. (No RAID configuration, though). > > > > I found that block size does influence performance greatly. With a block > > size of 131072 I got peak read performance at about 70MB/s, but that's > > all. > > I did not have the necessary knowledge at the time I have did the test > > last > > month, so I got only the result and thought that I have made something > > wrong and hoped someone to correct me with no luck :-( > > Hrm, i tried your block size, and the performance is even worse: > > # dd if=/dev/da0 of=/dev/null bs=131072 count=2000 > 2000+0 records in > 2000+0 records out > 262144000 bytes transferred in 8.688651 secs (30170852 bytes/sec) You may want to try other block sizes, like 65536, 262144, 524288, 1048576 or so. The peak performance block size depends heavily on hardware... Cheers, -- Xin LI <delphij frontfree net> http://www.delphij.net/ See complete headers for GPG key and other information.
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