SVN access became slow
Hi group, Suddenly SVN access became very slow on my PC. Before, everything ran fine. We have a small company network. * "Server" PC: Win10 Pro (1709), runs the svnserve.exe service, version 1.10.0 * My PC: Win10Pro (1803), using SVN 1.10.0-dev (Apr 14, 2018) * Other PC: Win10Pro (1803) When I run "svn info svn://server/RepoPath", I need to wait very long (over 40 seconds) before I get the response. When I use the server's specific IPv4 address, it responds immediately. When I use the server's specific IPv6 address, I get errors: svn: E170013: Unable to connect to a repository at URL 'svn://[fe80::c0a0:7afa:1cxx:xx9d]/RepoPath' svn: E730060: Can't connect to host 'fe80::c0a0:7afa:1cxx:xx9d': A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. When I run "svn info svn://server/RepoPath" from another PC on our network, it runs fine. I thought there might be a NetBIOS name resolution issue. But running a normal "ping server" immediately stars pinging via IPv6, so I figure NetBIOS works fine here. I have sniffed around with WireShark. I am really a novice here, so having misinterpreted my observations Is very well possible. But I noticed that the initial request (using the NetBIOS name) to the server goes via IPv6 addresses, but the data is returned via IPv4 addresses. This is on my PC, and also on the other PC in our network. Would this be normal? I already disabled the Windows firewall on both server and client, but to no avail. I'm not sure what to do next. Any clues? I'm not subscribed to this mailing list, so being explicitly CC:ed in any response would be appreciated. Thanks, Johannes
Re: SVN access became slow
On Tue, Jun 05, 2018 at 10:16:15AM +0200, Johannes van der Vegt wrote: > Hi group, > > > > Suddenly SVN access became very slow on my PC. Before, everything ran fine. > > > > We have a small company network. > > * "Server" PC: Win10 Pro (1709), runs the svnserve.exe service, > version 1.10.0 > * My PC: Win10Pro (1803), using SVN 1.10.0-dev (Apr 14, 2018) > * Other PC: Win10Pro (1803) > > > > When I run "svn info svn://server/RepoPath", I need to wait very long (over > 40 seconds) before I get the response. > > When I use the server's specific IPv4 address, it responds immediately. > > When I use the server's specific IPv6 address, I get errors: svnserve supports either IPv4 or IPv6, but not both at the same time. You could run two svnserve processes, one for IPv4 and one for IPv6. There is a '--prefer-ipv6' option which makes svnserve use IPv6 instead of IPv4, see the output 'svnserve --help'.
RE: SVN access became slow
Right... I installed a second service with the '-6' option. This did not make any difference. Doing more wireshark sniffing: - At first, SVN client tries connecting from the local-link IPv6 address. There is no response. Two TCP retransmissions fail as well. - Second, SVN client tries connecting from the temporary IPv6 address. There is no response. Two TCP retransmissions fail as well. - Finally, SVN client falls back to IPv4. This is successful. The other client PC (Win10 Home 1803) runs an older SVN client (v1.9.7), and does not try IPv6 first; this one goes straight to IPv4. Running the 'svn info' command from that older version on my own PC also goes straight to IPv4. I believe there is no option to force the client to use IPv4?? (except specifically entering the IPv4 IP address) Have I found a bug? -Original Message- From: Stefan Sperling [mailto:s...@elego.de] Sent: Tuesday 5 June 2018 12:12 To: Johannes van der Vegt Cc: users@subversion.apache.org Subject: Re: SVN access became slow On Tue, Jun 05, 2018 at 10:16:15AM +0200, Johannes van der Vegt wrote: > Hi group, > > > > Suddenly SVN access became very slow on my PC. Before, everything ran fine. > > > > We have a small company network. > > * "Server" PC: Win10 Pro (1709), runs the svnserve.exe service, > version 1.10.0 > * My PC: Win10Pro (1803), using SVN 1.10.0-dev (Apr 14, 2018) > * Other PC: Win10Pro (1803) > > > > When I run "svn info svn://server/RepoPath", I need to wait very long > (over > 40 seconds) before I get the response. > > When I use the server's specific IPv4 address, it responds immediately. > > When I use the server's specific IPv6 address, I get errors: svnserve supports either IPv4 or IPv6, but not both at the same time. You could run two svnserve processes, one for IPv4 and one for IPv6. There is a '--prefer-ipv6' option which makes svnserve use IPv6 instead of IPv4, see the output 'svnserve --help'.
Re: SVN access became slow
On Tue, Jun 05, 2018 at 02:54:01PM +0200, Johannes van der Vegt wrote: > Right... I installed a second service with the '-6' option. This did not > make any difference. Why does this not work? This should work. Can you connect to the SVN service with telnet to the server's advertised IPv6 address on port 3690? Maybe svnserve is not listening on the correct IOPv6 address (see the --listen-host option)? > Doing more wireshark sniffing: > - At first, SVN client tries connecting from the local-link IPv6 address. > There is no response. Two TCP retransmissions fail as well. > - Second, SVN client tries connecting from the temporary IPv6 address. There > is no response. Two TCP retransmissions fail as well. > - Finally, SVN client falls back to IPv4. This is successful. > > The other client PC (Win10 Home 1803) runs an older SVN client (v1.9.7), and > does not try IPv6 first; this one goes straight to IPv4. Running the 'svn > info' command from that older version on my own PC also goes straight to > IPv4. > > I believe there is no option to force the client to use IPv4?? (except > specifically entering the IPv4 IP address) > Have I found a bug? I don't think there is a bug here. SVN will simply try addresses returned by your client system's DNS resolver in turn. Maybe you could configure your client system's DNS resolver to prefer IPv4 but that would not be a nice solution. If your SVN server has an IPv6 address but does not provide service on that address, this is expected behaviour. There is no way for the SVN client to know that it should not be trying this address. If you do not intend to provide SVN service over IPv6, you could also disable IPv6 entirely on the SVN server machine.
Re: SVN access became slow
Stefan Sperling wrote on Tue, 05 Jun 2018 15:33 +0200: > If your SVN server has an IPv6 address but does not provide service > on that address, this is expected behaviour. There is no way for > the SVN client to know that it should not be trying this address. Well, connecting to the IPv6 address on TCP port 3690 could return a TCP RST or an ICMPv6 "Host unreachable" or the like, as opposed to no response at all (which I presume is what wireshark is showing).
Re: SVN access became slow
On Tue, Jun 05, 2018 at 01:40:10PM +, Daniel Shahaf wrote: > Stefan Sperling wrote on Tue, 05 Jun 2018 15:33 +0200: > > If your SVN server has an IPv6 address but does not provide service > > on that address, this is expected behaviour. There is no way for > > the SVN client to know that it should not be trying this address. > > Well, connecting to the IPv6 address on TCP port 3690 could return a TCP > RST or an ICMPv6 "Host unreachable" or the like, as opposed to no > response at all (which I presume is what wireshark is showing). Yes, it sounds like something might be dropping packets somewhere.
