CD-ROM drive letter changed to the next available letter after an issue with the Storage appliance.


  • Server platform:Windows server 2008 R2 Enterprise.

    Last time we experienced an issue with the storage device we are using to  attach a disk to our server 2008 (virtual). This storage device is also providing storage to the ESX where the server 2008 is hosted.

    The drive configuration in the server was:

    System C:\

    Tools D:\

    Apps E:\

    CD-ROM F:\

    Some hours after the storage appliance issue, we realized the Application on the server was not working and then we restarted the server. After restarting the server we went to the file explorer and realized that the Apps volume had the drive letter F and the CD-ROM had the E letter assigned.

    I assume windows lost the Apps disk due to the SAN disconnection. Maybe the CD-ROM was also disconnected and when the Storage appliance was connected again the CD-ROM acquire the next drive letter it found, which was the letter E:. Then the Apps disk was also discovered by Windows and it assigned the next available letter, F:.

    I was looking for some MS knowledge base to see how Windows 2008 server assigns the letter to the CD-ROM and how we can permanently fix the letter assigned to the disks and the CD-ROM so that this issue won't happen again. As you know many applications use the path including the drive letter.

    I thought that when you set a CD-ROM drive letter, it remains forever as is, and that in case of a SAN disconnection Windows assigns the same letter the drive had before the disconnection.

    Please advice if you have some documentation about this. And let me know if you have any thoughts about what really happened to prevent this in the future.

    Thank you guys!! 

    Wednesday, May 07, 2014 10:18 PM


  • Hi, for the APP's drive it could had been assigned a new letter if the system did seen it as a new disk/partition.

    The partition was on your esx's LUN on the SAN ? (not an iSCSI connection from inside a VM?)

    Regards, Philippe

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    Thursday, May 08, 2014 4:05 AM