Windows – SQL Server support for symbolic links

sql serversymbolic-linkwindows

Does SQL Server 2008+ support symbolically linked directories when making backups and restoring DBs?

My own test made use of a mapped network drive, which I made it appear by symbolically linking it as a local backup directory. I attempted to make a backup of a database to this symbolic link but received an error in SSMS (SQL Server Management Studio) stating that it was "unable to open the backup device".

Answer:
Yes, SQL Server supports symbolic links, even over network shares provided SQL Server has the necessary permissions to access the network share.

Best Answer

Your issue has nothing to do with symbolic links; a mapped network drive only exists in the context of the user who mapped it: SQL Server runs in a completely different user context (unless you're running it under your own user account, which I don't think is the case), thus it simply can't see the same network drives you see.

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windows – How to Create a Symbolic Link

You can create a symbolic link with the command line utility mklink.

MKLINK [[/D] | [/H] | [/J]] Link Target

        /D      Creates a directory symbolic link.  Default is a file
                symbolic link.
        /H      Creates a hard link instead of a symbolic link.
        /J      Creates a Directory Junction.
        Link    specifies the new symbolic link name.
        Target  specifies the path (relative or absolute) that the new link
                refers to.

Symbolic links via mklink are available since Windows Vista and Windows Server 2008. On Windows XP and Windows Server 2003 you can use

fsutil hardlink create <destination filename> <source filename>

According to msdn.microsoft, Symbolic Links are NOT supported on FAT16/32 and exFAT. It seems Windows only supports them from or to NTFS-Partitions. Future Windows operating systems are likely to continue support for mklink.

You can read further information about this new feature on Microsoft TechNet, Junfeng Zhang's blog or howtogeek.com.

Linux – Find out symbolic link target via command line

Use the -f flag to print the canonicalized version. For example:

readlink -f /root/Public/myothertextfile.txt

From man readlink:

-f, --canonicalize
      canonicalize by following every symlink in every component of the given name recursively; all but the last component must exist

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Related Solutions

windows – How to Create a Symbolic Link

Linux – Find out symbolic link target via command line

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