[OpenAFS] Re: Fwd: Re: vos move slowness remedies?

Eric Chris Garrison ecgarris@iupui.edu
Tue, 26 Oct 2010 13:56:04 -0400

On 10/26/10 11:06 AM, openafs-info-request@openafs.org wrote:
> On Mon, 25 Oct 2010 17:03:21 -0400
> Eric Chris Garrison <ecgarris@iupui.edu> wrote:
>> > It could very well be firewall-related, it could be causing
>> > fragmenting and causing rx to retransmit.
> If you get a packet dump and are willing to share with the people here,
> we may be able to give you more information on what is being slow.

I have a dump I could share, but don't want to post it publicly.  If
someone from the list would like to look at a wireshark capture (taken
during a slow transfer), email me directly.

The analysis of the wireshark capture is this:

[root@rfs4 ~]# dumpcap -w /tmp/ecg1.dumpcap -a duration:60
File: /tmp/ecg1.dumpcap
Packets: 201081 Packets dropped: 28064
[root@rfs4 ~]# capinfos /tmp/ecg1.dumpcap
File name: /tmp/ecg1.dumpcap
File type: Wireshark/tcpdump/... - libpcap
File encapsulation: Ethernet
Number of packets: 201081
File size: 202985493 bytes
Data size: 199768173 bytes
Capture duration: 59.619958 seconds
Start time: Mon Oct 25 17:18:45 2010
End time: Mon Oct 25 17:19:45 2010
Data rate: 3350692.94 bytes/s
Data rate: 26805543.53 bits/s
Average packet size: 993.47 bytes

> Also, iperf should be able to give you more statistics than just
> bandwidth. Packet loss? Latency?

iperf is blocked between the campuses, it seems, but between two
machines (which also have the same slowness) on the same campus, I get this:

[root@rfs1 init.d]# iperf -c rfs4 -p 13713
Client connecting to rfs4, TCP port 13713
TCP window size: 64.0 KByte (default)
[  3] local port 33239 connected with port 13713
[  3]  0.0-10.0 sec  1.07 GBytes    920 Mbits/sec

So, nothing dropped for a straight iperf test at almost full bandwidth,
but over 10% dropped at 30Mb/sec for AFS vos moves.

> You have still not said what version of OpenAFS this is... various
> versions have better or worse RX performance.

We're currently running openafs-server-1.4.11-1.1.1 on all servers.