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 is1) 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 foldersYou 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 files5) 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.
@echo off
: 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.
No comments:
Post a Comment