On 08/21/2010 12:52 PM, Bill Davidsen wrote: > john wendel wrote: >> I've got a couple of boxes connected with wire and a gigabit ethernet >> switch. With F11 on the sending and receiving sides, I see a transfer >> speed of ~ 40 MB/s transfering large files. With F13 on the sending box >> (same box, just new software), I get a transfer speed of ~ 23 MB/s with >> the same files. The disk read speed on the F13 box looks to be ~ 75 >> MB/s, so it doesn't seem to be the bottleneck. >> >> I'm not sure where to start looking. Any help will be much appreciated. >> > Since you only changed the OS at the sending end, that lets out a slowing of > disk write on the receiver. Since you have tested the speed of disk reads and > found it adequate, it's likely that the issue is the network code on the sending > end. > > However... do check the speed of reading that particular file. Remember that > different parts of the disk are faster than others, even on Linux files > fragment, etc. The easy way to do this is: > dd if=my.file of=/dev/null > and dd will report the speed. You can see as much as 50% slower on inner tracts, > so it's at least a possibility. > Thanks for the help. Looks like the network speed is fine, the slowdown appears to be in "scp", which is how I was sending the files. Using ttcp the test the network speed, gives the following, > 8192000000 bytes in 69.96 real seconds = 114350.28 KB/sec Using ttcp to send one of the files gives the following result, > 1464370115 bytes in 18.84 real seconds = 75923.92 KB/sec, which is similar (a little faster) to the speed I see with scp in F11. F13 scp gives me 23.3 MB/s for the same file. Looks like I'll spend a little time poking at F13 scp and see if I can improve the transfer speed. Thanks for all your help. John -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
