Hi all,
I'm using OpenAFS over an OpenVPN WAN and am experiencing some strange issues and wanted to bounce some ideas off the developer community before I started looking through the source-code. Below is a graph of data transfer between a Linux fileserver and Linux client. It's a 512KB chunk written out from /dev/random. The capture was taken using tcpdump on the fileserver machine. I'm trying to work out why the fileserver keeps pausing like this. The last packet before the pauses is an ACK from the client with a mixture of 32 +ve and -ve acknowledgements. then silence between the server and client for 1.2 seconds. . then the fileserver transmits all of the NACK data packets before the rate picks up again. As the rate picks up, the client will NACK a data packet, and then subsequent ACK packets grow in length (in terms of the number of ACKS) until they reach 32, at which time there is another long pause. rxdebug -rxstats says: Average rtt is 0.104, with 17838 samples Minimum rtt is 0.000, maximum is 2.147 That's a pretty large maximum rtt and I was wondering if this was somehow skewing the calculation of the retransmit timeout value, somehow causing the fileserver to snooze before suddenly realising it should be retransmitting packets. Any thoughts you have will be much appreciated. The AFS versions are as follows in case it helps: 1.4.12 (on the server) 1.4.10 (on the client) Kind regards, Pete Peter Wells Lutra Consulting 23 Chestnut Close, Burgess Hill, RH15 8HN <http://www.lutraconsulting.co.uk> www.lutraconsulting.co.uk Tel: +44 (0)1444 848012 Mob: +44 (0)7704 781683 SIP: [email protected]
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