How to rotate external harddisks
With the cost of hard-disk dropping and capacity increasing, more and more installations are using them to store their backups, in place of the traditional tapes. Inevitably, users will ask: How do you to set up a scheme to rotate these external hard-disks, so that some of them can be brought off-site for insurance against a disaster?
The way to set up such a scheme is
1) UPGRADE TO BACKUP EXEC 2010 R2
If you have not done so, you should do so before proceeding further. I deliberately use capitals in the title because this is a crucial step if you want to automate the process. BE 2010 R2, not BE 2010, has a lot of enhancements in the handling of removable disks. With BE 2010 R2, when a disk is ejected from the media server, BE is able to sense this and mark the Backup-to-Disk (B2D) folder(s) on it off-line. When a disk is plugged in to the media server, BE 2010 R2 is able to sense this and mark the B2D folders on it on-line. These automatic status changes of the B2D folders are crucial to the successful automation of a disk swapping scheme.
For BE 2010 or older versions, there is a way to overcame this limitation, but it would require some work. I will cover this in a later section.
2) Define your B2D folders
Plug in your disks and define your B2D folders on them.
Define them as you would define B2D folders on internal disks. Do not use Removable B2D folders unless you are using CDR-RW, DVD-RW, ZIP or REV. For USB or eSata drives, use normal B2D folders.
Another good thing about using BE 2010 R2, is that you do not have to worry about the drive letters of your hard-disk. If the drive letter got changed after you have defined your B2D folders, BE 2010 R2 will handle the drive letter change automatically. For older versions of BE, you got to make sure that the drive letter stays the same.
3) Define a device pool for your B2D folders
You need to define a device pool so that your job can target this device pool. On the Devices tab, right-click on Device Pools to define a new pool.
Depending on which B2D folder is on-line when your job runs, your job will write to that folder. Otherwise, you need to define one job per B2D folder and target each job to one B2D folder.
4) Define a media set to keep your .bkf files
5) Define a job
Define a job which targets the device pool and media set defined above.
Considerations when using older versions of Backup Exec
If you are using a version of BE older than BE 2010 R2, then certain things are different as they do not have the external disk handling capabilities of BE 2010 R2.
a) Fix the drive letters of your external disks
BEFORE you define your B2D folders on your external disks, make sure that they will always have the same drive letters when they are connected to the media server. You can either user one drive letter for all your disks or one drive letter per disk. If the drive letter changes after you have defined the B2D on the disk, then BE will not be able to recognize it even though the disk is on-line.
Windows assign drive letters to drives from the start of the alphabet and go higher accordingly. Typically, when you plug in the drive, it would be assigned E:, F: and so on. Let’s say, your drive was assigned as the F: drive when you plugged it in to the media server and you defined your B2D folder with this drive letter. If there is already a F: drive when you next plug it in, it would be assigned the next higher unused drive letter. Let’s assume that it is now the G: drive. When BE tries to write to the B2D folder, it would not be able to find the B2D folder as the drive letter has changed and it would mark the folder either as “Low disk space” or off-line.
To fix the drive letter for an external drive, go to Start à Run à diskmgmt.msc, right-click on the drive and select Change Drive Letter and path.
I normally like to assign drive letters in the middle of the alphabet, like M, N, O, etc., where it is unlikely to clash with some other drives. You should not use the end of the alphabet like X, Y and Z because Windows normally assign these to mapped drives.
If in the future, for whatever reason, the drive letter for the disk drive changes from what is assigned. Use the method above to change it back the assigned drive letter.
b) Bring B2D folders on-line
When you use a device pool, BE will try to use the first available device in the pool and go down the line. When it encountered a B2D folder whose drive is not on-line, it will mark it either “Low disk space” or off-line.
If the B2D folder is marked offline, even if you have plugged in the drive before the next job, this status will not change and BE will not be able to the B2D folder. You must either
- go to the BE console, right-click on each of the off-line B2D folders in the Devices tab and select on-line, or
- use BEMCMD to pause and un-pause the B2D folder.
For the second method, you can use the Windows scheduler to run a batch file with the following commands.
: pause the B2D folder
C:\Program Files\Symantec\Backup Exec\bemcmd -o60 -d:”Backup-to-Disk Folder 1”
: un-pause the B2D folder
C:\Program Files\Symantec\Backup Exec\bemcmd -o61 -d:”Backup-to-Disk Folder 1”
Put the name of your B2D folder between the quotes and repeat the above pair of commands for each B2D folder that you have. If you are unsure what your B2D folder names are, run the following command in a command prompt window and they would be displayed.
C:\Program Files\Symantec\Backup Exec\bemcmd -o68
I have tested this method with BE 12.5, so it should be good for BE 2010. I am not sure whether the –o60 switch exists for BE 12.0 or older versions of BE.
It is no good trying to schedule an inventory job for the B2D folder. The job will fail if the folder is marked as off-line.
As you can see, there are quite a lot of gymnastics that needs to be done before you can rotate external disks if you are using a version of BE that is older than BE 2010 R2. Hence, I would like to reiterate again, UPGRADE TO BE 2010 R2 if you are not already on it.