Backup file extensions

Thank you Elizabeth for your reply.

I assume .bak is the extension for a full backup. What are the extensions for the other options (differential, incremental, …)?

Thanks again

D

.bak is the windows extension for backups.

http://technet.microsoft.com/en-us/library/cc875820.aspx

go above and read the info

but yes they are the same, the date/time is the difference in the .bak files

if you have set up for example differential backup for every tuesday then it will be dated for each successive tuesday with the .bak extension.

if you have it appended to the current .bak file then the file will remain but the date will change.

you would have to know if it is incremental or differential and if they were appended or seperate

Differential backup

Differential backups copy those files that have been changed since the last full backup took place. So if a full backup was done on Day 1, Day 2's differential will copy all of the files that have changed since Day 1's backup copied everything. Day 3's differential backup will also copy all of the files that have changed since Day 1's full copy was made.

The key advantage of differential backups comes when data needs to be restored. Because a full backup was taken and the differentials copied everything that subsequently changed, only the full backup and the latest differential need to be restored.

The main disadvantage is that the size of the differential copy increases each time a backup is taken until the next full version is made, which can begin to impinge on backup window duration.

Incremental backup

Incremental backups copy all of the files that have changed since the last backup was made. They do this whether the last backup was a full one or an incremental copy. So if a full backup was done on Day 1, Day 2's incremental will back up all of the files that have changed since Day 1. Likewise, Day 3's incremental backup will only copy those files that have changed since Day 2's incremental took place.

The main advantage to incremental backups is that fewer files are copied in the period between full backups, which means you will get a shorter backup window. The main disadvantage is that when you want to carry out a complete restore, the most recent full backup and all of the subsequent incremental copies must be restored. This can make the restore process a lengthier one than when using a full backup plus the most recent differential copies only.

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• If you want to append this backup file to previous backup files, click Append this backup to the media. This option adds the new backup to the existing backup file so that you can maintain all previous backups in one file. This option is useful if you ever want to restore a backup from a specific day. Be aware that the size of the backup file will grow with each new backup. You might want to monitor the file size to make sure that it does not fill up your hard disk over time. If the file becomes too large, you might consider saving the file to an external hard disk. Or, if you are concerned about the file using too much hard disk space, select Replace the data on the media with this backup instead.
• If you want to overwrite previous backup files with this backup file, click Replace the data on the media with this backup. This option is useful if you only want to maintain the current backup and do not care about keeping the previous backups. Or, use this option if you are concerned about the file using too much hard disk space on your computer.

So you have to know what type of backup was done and then go by the dates.

Ok, last question. If you are cleaning up a friend's computer USB drive and wish to eliminate old .BAK files. How do you know that you are not destroying core files that later backups are depending on?

Thanks for all your help.

D