Thanks for ur response Conrad. But the file system is not unmounted. Still it 
was mounted only. 

The difference I see is the production host uses VxVM 5.0, which is synched to 
BCV and mounted to a host where VxVM 4.0 is the VM. Checked with Symantec abt 
this, they said "the Intent log of both version differes, but there will be no 
problem accessing the files in the host with VxVM 4.0". 

Not sure if the I/O error issue is caused by the incompatible VxVM.

+----------------------------------------------------------------------
|This was sent by anandhg AT gmail DOT com via Backup Central.
|Forward SPAM to abuse AT backupcentral DOT com.
+----------------------------------------------------------------------

To sign off this list, send email to listserv AT listserv.temple DOT edu and 
type "signoff networker" in the body of the email. Please write to 
networker-request AT listserv.temple DOT edu if you have any problems with this 
list. You can access the archives at 
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER