On Tue, 1 Jan 2002 09:13, Jeff Waugh wrote: > <quote who="Jason Lim"> > > > What do you think would be the best way to duplicate a HD to another > > (similar sized) HD? > > dd, using a large buffer size for reasonable performance
I've just done some tests on that with 33G partitions of 46G IDE drives. The drives are on different IDE buses, and the CPU is an Athlon 800. It seems that a buffer size of 4K (page size on Intel) is much better than the default of 512b (no surprise there). However a buffer size of 1M uses more system time than 4K and gives the same elapsed time. So it seems to me that page size is probably a good buffer size to use. # time dd if=/dev/discs/disc0/part6 of=/dev/discs/disc1/part6 dd: reading `/dev/discs/disc0/part6': Input/output error 67376544+0 records in 67376544+0 records out real 61m59.876s user 1m6.110s sys 13m46.200s # time dd if=/dev/discs/disc0/part6 of=/dev/discs/disc1/part6 bs=4k dd: reading `/dev/discs/disc0/part6': Input/output error 8422068+0 records in 8422068+0 records out real 44m56.078s user 0m5.350s sys 5m28.270s # time dd if=/dev/discs/disc0/part6 of=/dev/discs/disc1/part6 bs=1024k dd: reading `/dev/discs/disc0/part6': Input/output error 32898+1 records in 32898+1 records out real 44m55.056s user 0m0.170s sys 7m46.130s -- http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/projects.html Projects I am working on http://www.coker.com.au/~russell/ My home page
