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How do I permanently assign a drive letter to external hard drives?

Created: 29 Dec 2008 • Updated: 22 May 2010 | 15 comments

I have 5 external hard drives (eHD) that I want to use in a rotation for off-site backups, with the same backup job. The problem I am experiencing is that when I replace 1 eHD with another, no drive letter is assigned to the new eHD, i.e. the drive does not show in Windows' My Computer, so the BEWS backups fail. If I manually assign a letter to these eHD using the Windows Disk Management utility then it works. How can I permanently assign the same drive letter (E:) to these 5 eHD, so that when I replace them the drives are automatically assigned the right letter?


Here is more background info:

OS: Windows Server 2003 Standard SP2

BEWS 12.0

Connection between BEWS media server and eHD: Firewire 800

The eHDs are LaCie d2 quadra 500 GB (they are all the exact same model). 



Comments 15 CommentsJump to latest comment

Kevin Cotreau's picture

This is not recommended. You should have one drive for one letter. Create separate jobs as needed. Make your B2D folders "non-removable" even though you will remove them. It is more stable.


Read these previous threads where I have posted about this and the links given in them:







Marcelo Pineyro's picture

Thank you for your reply Kevin. The issue I am experiencing is more of a Windows issue than a Backup Exec issue in that Backup Exec will successfully make backups to my various external hard drives as long as those hard drives have the right letter. So aside from Backup Exec best practices, do you understand how letter assignment in Windows works? In particular, why is it that when I format an external HD with a given letter, and do the same with another identical HD, when I switch between these HDs, Windows does not automatically assign any letter to these devices, in fact, they don't show up in My Computer until I manually assign them a drive letter using Windows Disk Management utility? I did some research in Microsoft's knowledge base and using Google, but I could not find an explanation of why this happens, or how to assign a drive letter permanently to a device.


Right now I intend to do a 1 week roation, but I may very well go to a 2 week rotation in the near future. I am not willing to have 10 different backup jobs for the daily backup, the weekly backup, etc, especially when it involves pre and post script commands, since I am backing up wirtual machines. I sure hope there is a more IT-Admin-friendly option.



Kevin Cotreau's picture

I understand that that is a Windows issue, but the point is that you don't want to do that with regards to BE. In my opinion, you are asking for problems related to BE.


I suspect from a Windows standpoint, other than using Disk Manager and assigning the same letter to each, I am not sure without doing extensive testing and research myself.


Regarding multiple jobs, you should read some of my other posts regarding this. All too often, people try to cram too many variables into one job, and it causes them headaches.

Marcelo Pineyro's picture

Kevin, would you please share some of the problems that you have run into in the past, or that you know others have run into, by trying to use 1 backup job with various removable devices that have the same drive letter?


With respect to multiple jobs, I definitely want to have numerous backup jobs, so when they're not 100% successful, it's easier for me to identify what actually was not backed up. I find it easier to manage too to have different jobs for different sets of files. This is precisely why I dread the idea of having 5 or 10 different jobs for each backup set!



Kevin Cotreau's picture

I personally have never had an issue, but answering questions here, I have seen quite a few. With external USB drives, the solution is almost always one letter for one drive as stated , and referenced in one of the threads above that you should have read.


in particular this is relevant:


It states: "Backup Exec does not support swapping different hard drives in an attempt to use different physical devices for the same backup-to-disk folder in Backup Exec", which is exactly what you are trying to do.

Marcelo Pineyro's picture

Kevin, you should read more up-to-date information. I read that article prior to posting in this forum, but took it for what it is, an article that was last updated on June 30, 2005. The earliest version that that article is applicable to is version 10, I’m using 12.0. Prior to posting here Ialso started a support request with Symantec, and a support engineer sent me adocument that explains how to use various USB external hard drives in arotation, all with the same drive name. It is a Word document that I was sent,so I have no link that I can post here, and I see no option to upload files tothis discussion. But the title of the document is "How to Use External USBDisk Drives on a Rotation Scheme with VERITAS Backup Exec (TM) for WindowsServers." and explicitly state that one makes sure that the drive nameassigned to all drives is the same. The problem is that Windows does notmaintain the assigned drive letter when I replace one drive with another one.


Thank you for your time.

Kevin Cotreau's picture

That is true, but it does not change what I have seen in practice even with version 12. Good luck.

pmbrentjr's picture

The information you read is correct Marcelo, window assigns the drive letter as the POST ( power on Self Test ) executes and recognizes the same hardware device ID hasnt changed from last POST. If you remove that HD, say and put a different one in, Windows recognizes it as a different periphial and therfore doesnt automatically assign it a Drive letter, and will default to the next available drive letter working its way from a-z in the alphabet.

Marcelo Pineyro's picture

Thank you for your message "pmbrentjr" (I would address you by name, but you didn't include it in your post). I haveseen that behavior too, that Windows will assign the next available letter inalphabetical order. But what I am observing is that no letter at all isassigned. By the way, is there any good article that you know of that explains how Windows assigns drive letters?


I actually tried connectingthe HDs to a laptop running Windows XP via USB. There it works just fine, I canrotate the drives and they always get the same letter assigned. I thought maybethe issue was with the Firewire card in the server, so I tried the USBconnection between the drives and the server, but it’s the same thing as withthe Firewire, no letter is assigned. When I open Disk Management I see thepartition and it says healthy, but no letter is associated with it.


So I am downloading some Windowsupdates to my server to see if that makes any difference. I am not too hopefulsince they are mainly security updates, but we’ll see. Based on these last testsI made it looks to me that the issue has to do with the version of Windows inthe server (2003 Standard SP2).

t.patrick's picture


I would like to see that document, if you wouldn't mind emailing it {Removed to prevent spam}  When I swap a USB drive in, I just assign the letter using windows, no big deal to me.

Since I just recently started trying to use USB instead of tapes, my worry is how well does BE 12.5 work when you want to restore from a USB drive that may be several months old. do you initialize and catalog in the same way you did with Tapes? Thanks.

Message Edited by IanSee on 01-06-2009 04:04 PM
Marcelo Pineyro's picture

Here is the text of that document (pictures omitted):


How to Use External USB DiskDrives on a Rotation Scheme with VERITAS Backup Exec (TM) for Windows Servers.


In order to use the External USB Disk Drives on a rotation scheme,follow the steps given below:

1. Attach the first USB Disk Drive to the computer. Make sure thatWindows is able to detect the External USB Disk Drive. Only then Backup execwill be able to backup data to the External USB Disk Drive. Backup Exec canonly backup data on to the External USB Disk Drive using "Removable Backup-To-Disk"option available in Backup Exec for Windows Servers.

2. Create a Removable Backup-To-Disk folder for the attachedExternal USB Disk Drive. For more information on how to create a RemovableBackup-To-Disk folder, refer to the related technotes.

3. Remove the attached External USB Disk Drive.

4. Attach the Second External USB Disk Drive. Make sure thatWindows detects and the drive name is same for the second External USB DiskDrive as that of the first External USB Disk Drive.

5. On the navigation bar, click Devices ( Figure 1 )

6. Right click on the newly created Removable Backup-To-DiskFolder for the External USB Disk Drive. ( Figure 2 )

7. Select Scan option ( Figure 3 )

8. This will create the necessary files required. It will be sameas the files created for the first External USB Disk Drive. Repeat steps from 3- 7 for all the External USB Disk Drives which are to be used for the rotationscheme.

Once all the USB Disks areset then set the rotation scheme by creating a drive pool which will haveRemovable Backup to Disk folder created for the External USB Disk Drives as thetarget source for backup 

Wellsoft's picture

I can tell you that I had the exact same issue and thanks to Kevin's advice, I am golden now. And, yes, I had to create a job for each drive, no biggie make the first one then copy and tweak the subsequent jobs. Just because a concept is older doesn't invalidate it.

Kevin Cotreau's picture

Thanks for the nod. Some people would rather beat their head against the wall rather than just doing it a way that works.


The other one I see here a lot is people trying to migrate their BE install. I am not talking about an in-place upgrade from 11d to 12x. Most installs are not that complicated that you can't just reinstall and replicate the settings in under an hour tops. They would rather spend weeks solving the problem. There is nothing that can't be gotten off the old tapes after the fact if you really need it, and it is probably faster to run an inventory and catalog job on every tape than it is to solve an issue related to migrating to a new BE version, new server name, or new domain.

Kevin Cotreau's picture

Other than responding to previous posts that show up in my mailbox, like this one, I am done for now answering new questions indefinitely. I have deleted the links from my favorites. Twice yesterday after offering to help via remote for free, my motives were questioned. Sorry, but anyone who thinks I was doing this to hack them is a moron since I clearly am a professional network consultant, who works for himself. Anyone who ever read my posts would realize this. I am also 47 years old, which is not the typical age to be a hacker.


I spent two hours (each) remotely with a few people with configuration problems, who were all ecstatic. We mostly chatted while on the phone while I straightened out their problems and they learned by watching. I also would show them my setup.


I did all this posting and offering to help remotely because I was sick for a couple of weeks, then there were the holidays, so I had some time and I enjoyed helping people. I also enjoyed talking shop since I like what I do for work.


For those, who I helped, and who demonstrated a little appreciation in their words here, and by taking the time to click "solved", I thank you.

Wellsoft's picture

I hear ya, hence why I oprefer machines and dogs to humans! LOL....I would like your opinion on cataloging the external drives....I have not been doing that....think I should? Haven't had to restore yet.....but......