[ic] Using external database causing intermittent errors

[DB]

Hi - I've completed my test cluster configuration of two identical 5.4.2 
standard demo stores on two separate machines. For both stores I used 
'test.domain.com' as the server name when I ran makecat, and for both I 
used the same user and database names.

The catalog is accessed from http://test.domain.com
Machine 1 hosts test1.domain.com
Machine 2 hosts test2.domain.com
Both domains include test.domain.com as a ServerAlias in their 
httpd.conf files. Both machines have mysql sessions enabled. The 
machines are connected to each other via gigabit.

Everything seems to run just fine until I tell the test2 store to use 
the identically-named database located on test1's server (instead of 
test2's own local version of the database). Once I do that, I get 
intermittent "premature end of script header" errors. If I hit reload on 
the browser when I get such an error, most often the page will load 
normally.

The clustering server is running HAproxy (http://haproxy.1wt.eu/) and 
while simple to configure, this software causes the cluster members to 
see all requests as originating from the IP of the HAproxy server. But 
since the setup works ok with each machine using a local database, I'm 
not sure I can say this is really the problem.

Can anyone suggest why having one member use the other's databse would 
cause such errors? Obviously both members must share a common database 
for a real-world IC cluster to be workable. Any thoughts are welcome.

Typical error from test2's /usr/local/interchange/error.log:
111.22.111.22 EokMAfzY:111.22.111.22 - [02/February/2008:13:38:12 -0500] 
test_store /cgi-bin/test_store/error/HTTP_INTERNAL_SERVER_ERROR.html.var 
Died in server spawn: Storable binary image v2.7 more recent than I am 
(v2.6) at blib/lib/Storable.pm (autosplit into 
blib/lib/auto/Storable/thaw.al) line 358, at 
/usr/local/interchange/lib/Vend/Session.pm line 420

This error seems fairly descriptive, but sadly I don't understand it.

Typical error from test2's httpd error log:
[Sat Feb 02 13:38:12 2008] [error] [client 111.22.111.22] Premature end 
of script headers: test_store, referer: 
http://test.domina.com/cgi-bin/test_store/admin/gentable.html?id=EokMAfzY&mv_pc=27

Any thoughts or suggestions are welcome.

DB