[OpenAFS] some afs clients are unreachable afs servers from time to time.

[TIARA System Man]

dear guys,

i have encountered some afs clients are unreachable afs servers once a
mounth. after i restart afs servers services and restart afs clients,
the problem is gone. the following are one of my afs clients messages:

Jan 18 04:01:10 soleil kernel: afs: Waiting for busy volume 536871111
in cell tiara.sinica.edu.tw
Jan 18 04:01:10 soleil kernel: afs: Waiting for busy volume 536871111
in cell tiara.sinica.edu.tw
Jan 18 04:01:10 soleil kernel: afs: Waiting for busy volume 0 in cell
tiara.sinica.edu.tw
Jan 18 04:01:10 soleil kernel: afs: Waiting for busy volume 536871111
in cell tiara.sinica.edu.tw
Jan 18 04:01:10 soleil last message repeated 7 times
Jan 18 04:03:33 soleil kernel: afs: Lost contact with volume location
server 140.109.xxx.xxx in cell tiara.sinica.edu.tw
Jan 18 04:03:33 soleil kernel: afs: Lost contact with volume location
server 140.109.xxx.xxx in cell tiara.sinica.edu.tw
Jan 18 04:03:34 soleil kernel: afs: Waiting for busy volume 536871111
Jan 18 04:05:35 soleil last message repeated 4 times
Jan 18 04:05:35 soleil last message repeated 2 times
Jan 18 08:30:12 soleil kernel: WARM shutting down of: CB... afs...
BkG... CTrunc... AFSDB... RxEvent... UnmaskRxkSignals... RxListener...
Jan 18 08:30:12 soleil kernel: WARNING: not all blocks freed: large 1 small 4
Jan 18 08:30:12 soleil kernel:  ALL allocated tables
Jan 18 08:30:14 soleil kernel: Starting AFS cache scan...found 1268
non-empty cache files (40%).
Jan 18 08:32:23 soleil kernel: afs: Lost contact with volume location
server 140.109.xxx.xxx in cell tiara.sinica.edu.tw

could anyone give me hits to debug this problem? thank you. those
machines are installed scientific linux 5.x x86_64. the afs versions
are openafs-client-1.4.7-68.SL5.x86_64 and
openafs-server-1.4.7-68.SL5.x86_64.

best, sam
-- 
Sam Tseng
Academia Sinica
Institute of Astronomy and Astrophysics
Tel: +886-2-3365-2200 ext 742
Fax: +886-2-2367-7849