hi, I recently got a seagate cheetah (ST336753FC, 15k.3 RPM 37GB) harddrive that sits in my JMR Fortra 2G6 array. I'm running Linux 2.6, using sg3_util.1.13 My seagate is mapped to /dev/sdb I run the following: 1.)time sg_dd if=/dev/zero of=/dev/sdb bpt=256 count=1200000 a.) it finishes on average around 10 seconds 2.)time sg_dd if=/dev/zero of=/dev/sdb bpt=255 count=1200000 a.) this finishes on average around 18 seconds Why is there such a big difference? In a program that I wrote, --one pc reads data from one hd --transfers it over a closed network --another pc writes the data received to another hd When I had both the hd being as seagate cheetah (ST318453FC, 15k RPM 17GB), I was getting good overall (transfer + read/write) speed around 300Mb/s. The drives sit in the JMR Fortra 2G6 array. But when I replaced one of these with my new 37GB hd, i get weird resuls. --if the 37GB replaced the one data is written to, my overall speed drops by a factor of 100Mb/s --if the 37GB replaced the one data is read off of, my overall speed remains at 300Mb/s. Any help would be greatly appreciated. THANKS!!! -Ying __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
