I would like to know if i delete a job will the job history also gets deleted.
The Job History would NOT get deleted if you delete a job. The Job History would get deleted based on the 'Delete Aged data' setting under the following option: Backup Exec Icon > Configuration and Settings > Backup Exec Settings > Database Maintenance.
Advanced Technical Support Engineer, Symantec Corporation
I have one more issue "When i am backing up my exchange server i get an error cannot extract mailbox messages from the exchange backup (V-79-57344-915) and unable to determine ADAMM media identification catalog query failed (v-79-57344-37956). "
Bash, what is the Backup Exec and Exchange version that you are using?
Also, based on the error message, you could start by referring to the following article and ensure that requirements for performing a backup of Exchange are met: http://www.symantec.com/business/support/index?page=content&id=HOWTO24128
I have already installed the exchange agent on the server and i am using backup exec 2012 SP3. It was working fine suddenly it started giving me errors "The backup options or selections for this job have changed since the last time it ran(V-79-57344-862)" even though i did not make any changes. Error 2 " unable to determine ADAMM media identification catalog query failed (V79-57344-37956)". Any help !
Bash, for the error 'Unable to determine ADAMM media identification. Catalog query failed' you need to refer to Solution 3 of the following article: http://www.symantec.com/business/support/index?page=content&id=TECH43264
Note: I am assuming that you are getting the above error for a Duplicate Backup job/stage.
For the issue associated to 'The backup options or selections for this job have changed since the last time it ran', you need to refer to the following: http://www.symantec.com/business/support/index?page=content&id=TECH197761