Forum Discussion

gjisrael1420's avatar
gjisrael1420
Level 3
13 years ago

Mixing Incremental and Differential backups

I am Using Symantec backup exec 2010 with the following backups: full backups - last saturday of the month Differential backups - last saturday of every week incremetnal backups - end of every ...
2010
Backup and Recovery
Backup Exec
  • pkh's avatar
    pkh
    13 years ago

    will the last differentail data holds all the data modified from the last full backup even if  incremental backups are also involved in the middle.

    No.  The differential backup will only contain files modified since the last incremental backup or full backup. Incremental and full backups resets the archive bit.

    So in your case, if you need to restore something in the middle of the second week, you would need to restore the full backup plus the first week's incremental followed by the latest differential.

    It is a bad idea to mix differential and incremental backups because it can get confusing and confusion is the last thing you want when your server is down.  It is better to stick to a simple scheme like full + incremental or full + differential.  Better yet, just do full backups every time if your backup window permits.  Doing just full backups means that you only have one backup to restore and it is the fastest amongst all the methods.

    All the above is applicable regardless of whether you are using the modified time or archive bit methods.

pkh's avatar
pkh
Moderator
13 years ago

will the last differentail data holds all the data modified from the last full backup even if  incremental backups are also involved in the middle.

No.  The differential backup will only contain files modified since the last incremental backup or full backup. Incremental and full backups resets the archive bit.

So in your case, if you need to restore something in the middle of the second week, you would need to restore the full backup plus the first week's incremental followed by the latest differential.

It is a bad idea to mix differential and incremental backups because it can get confusing and confusion is the last thing you want when your server is down.  It is better to stick to a simple scheme like full + incremental or full + differential.  Better yet, just do full backups every time if your backup window permits.  Doing just full backups means that you only have one backup to restore and it is the fastest amongst all the methods.

All the above is applicable regardless of whether you are using the modified time or archive bit methods.