Re: Slow network with F13 [SOLVED]
Roberto Ragusa wrote: Bill Davidsen wrote: Roberto Ragusa wrote: john wendel wrote: Looks like I'll spend a little time poking at F13 scp and see if I can improve the transfer speed. Maybe you are using compression? Compression is a disadvantage when the network is fast (gigabit); you just spend CPU time. Then there is encryption. That can't be turned off. I would love an option --no-crypto for scp or rsync+ssh on local networks, but there is none: you are forced to turn to rcp or rsh or nc tricks. There actually is a patch to provide encryption none to improve speed and reduce CPU for trusted connections. HINT: sure would be a nice addition to Fedora FC14!! It's really desirable for doing scp or ssh to/from a VM from the host. Why spend CPU encrypting a connection which is as trusted as possible? Note that for just file transfer netcat can be useful if you have the firewall set to allow it. I didn't know about this patch. There is also a bug on Ubuntu (54180), but it looks like nothing has moved. So let's hope we will have it someday. BTW, about compression, we just have gzip. Where is LZMA? It would be useful on slow links (e.g., all ADSL uplinks) :-) Maybe extra ciphers and compressions could be handled as plugins. Well good idea, but the patch I mentioned is out for inclusion now, and so represents a minimal effort. I agree that plug-ins would be nice, but they must not replace existing code or compression, for security reasons. If a plugin could be compromised... better to compile stuff in, what's there is adequate, the none crypto is a special case. -- Bill Davidsen david...@tmr.com We have more to fear from the bungling of the incompetent than from the machinations of the wicked. - from Slashdot -- users mailing list users@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Re: Slow network with F13 [SOLVED]
Bill Davidsen wrote: Roberto Ragusa wrote: john wendel wrote: Looks like I'll spend a little time poking at F13 scp and see if I can improve the transfer speed. Maybe you are using compression? Compression is a disadvantage when the network is fast (gigabit); you just spend CPU time. Then there is encryption. That can't be turned off. I would love an option --no-crypto for scp or rsync+ssh on local networks, but there is none: you are forced to turn to rcp or rsh or nc tricks. There actually is a patch to provide encryption none to improve speed and reduce CPU for trusted connections. HINT: sure would be a nice addition to Fedora FC14!! It's really desirable for doing scp or ssh to/from a VM from the host. Why spend CPU encrypting a connection which is as trusted as possible? Note that for just file transfer netcat can be useful if you have the firewall set to allow it. I didn't know about this patch. There is also a bug on Ubuntu (54180), but it looks like nothing has moved. So let's hope we will have it someday. BTW, about compression, we just have gzip. Where is LZMA? It would be useful on slow links (e.g., all ADSL uplinks) :-) Maybe extra ciphers and compressions could be handled as plugins. -- Roberto Ragusamail at robertoragusa.it -- users mailing list users@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Re: Slow network with F13 [SOLVED]
john wendel wrote: Looks like I'll spend a little time poking at F13 scp and see if I can improve the transfer speed. Maybe you are using compression? Compression is a disadvantage when the network is fast (gigabit); you just spend CPU time. Then there is encryption. That can't be turned off. I would love an option --no-crypto for scp or rsync+ssh on local networks, but there is none: you are forced to turn to rcp or rsh or nc tricks. -- Roberto Ragusamail at robertoragusa.it -- users mailing list users@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Re: Slow network with F13 [SOLVED]
Roberto Ragusa wrote: john wendel wrote: Looks like I'll spend a little time poking at F13 scp and see if I can improve the transfer speed. Maybe you are using compression? Compression is a disadvantage when the network is fast (gigabit); you just spend CPU time. Then there is encryption. That can't be turned off. I would love an option --no-crypto for scp or rsync+ssh on local networks, but there is none: you are forced to turn to rcp or rsh or nc tricks. There actually is a patch to provide encryption none to improve speed and reduce CPU for trusted connections. HINT: sure would be a nice addition to Fedora FC14!! It's really desirable for doing scp or ssh to/from a VM from the host. Why spend CPU encrypting a connection which is as trusted as possible? Note that for just file transfer netcat can be useful if you have the firewall set to allow it. -- Bill Davidsen david...@tmr.com We have more to fear from the bungling of the incompetent than from the machinations of the wicked. - from Slashdot -- users mailing list users@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
RE: Slow network with F13 [SOLVED]
There actually is a patch to provide encryption none to improve speed and reduce CPU for trusted connections. That would be cool, but you can avoid this by rsyncing over an alternative transport, like rsh to a remote rsync daemon which you can instantiate off the cmd line trivially... jlc -- users mailing list users@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Re: Slow network with F13 [SOLVED]
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, 819200 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@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
