Issues with user.sub files - subscription files hangs system.

[Adam D]

Adam D wrote:
> I have noticed this error in the log:
> Sep 12 18:57:44 vts-post cyrus/imap[19629]: IOERROR: locking
> /var/lib/cyrus/domain/W/domain1/user/A/userbox.sub: Interrupted system call
>
> Soon afterwards I notice imapd runs at 99.8 % and I can not kill the
> process.  It looks like the file is locked and can't be written to?  I
> saw another file called userbox.sub.NEW but even that files can't be
> read.  When I attempt the terminal freezes.  I also noticed the system
> can't be rebooted as well.  I don't know what could be causing this. 
> Does anyone have any incite? 
>
> Example:
> -rw------- 1 cyrus mail  31K Sep 12 18:22 user.seen
> -rw------- 1 cyrus mail  14K May 24 10:21 user.sub
> -rw------- 1 cyrus mail 4.0K Sep 11 18:25 user.sub.NEW
>
> I can view user.sub but it has not been updated since May and the
> user.sub.NEW apears as an binary file or a DB
>
>
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+ 
> COMMAND                                 
> 19484 cyrus     25   0  154m 4772 3776 R 99.8  0.8   7:51.32 imapd     
>
> -Adam

I am figuring this has to do with the user.sub file and still locked. 
Any time subscription is access imap creates a new file user.sub.NEW
instead of user.sub and becomes a run-a-way process. 

No matter what I do or know can change the subscription based files..
flat or skipless.  Right now the file  is a flat file and while
converting it to skiplist I get the same issue as above - imap process
or in this case cvt_cryusdb ll the processor resources and becomes a
run-a-way process.

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+ 
COMMAND                                
 8621 root      25   0 86848 2284 1848 R 96.1  0.4  81:51.64
cvt_cyrusdb         

My log shows this:
Sep 16 20:25:27 mail cyrus/cvt_cyrusdb[8545]: skiplist: invalid magic
header: /var/lib/cyrus/domain/domain1/user/user1.sub

Also when I try to read the "converted" user1.sub file using less I lose
any ability with the terminal.  I am so at a loss and have been really
digging around for days trying to figure this out..

We are using Ubuntu 8.04 on this particular amd 64 box running virtually
within xen.

Please help.
-Adam