This topic describes SnapManager support for volume mount points, which is new in SnapManager 2.1:
Windows supports up to 26 drive letters. For SnapManager to migrate, back up, and restore SQL Server databases, SnapManager requires a minimum of two LUNs to hold SQL Server data, transaction log files, and the SnapInfo directory. You can allocate a maximum of 25 drive letters. Additionally, certain SnapManager operations require more drive letters for the following:
With SnapManager 2.1 for SQL, your configuration is not limited to the 26 drive letters supported by Windows. By using the NTFS volume mount point support that is part of SnapDrive, SnapManager can manage SQL databases that are stored on mounted volumes as well as those stored on standard Windows volumes.
The following table summarizes the environments in which SnapManager 2.1for SQL supports volumes mounted on Data ONTAP LUNs. Additional details regarding limitations and enforcement imposed by SnapManager are described in subsequent sections of this document.
1 Windows 2000 Server does not support mounted volumes in a cluster
SnapManager imposes the following restrictions.
An NTFS volume that hosts mount points cannot store SQL database files. However, transaction log files can reside on such a volume.
Following are the mounted volume restrictions with SnapManager:
A mounted volume is a volume that is mapped to a folder and referenced by a mount point that is created in an empty directory. The SnapManager user interface represents a mounted volume based on the path of a volume mount point that references that mounted volume, as follows:
DriveLetter:\MountPointName
S:\ My_Mount_Point
SnapManager for SQL provides a specific naming convention for multiple databases using either the same or two different LUNs, The SnapManager user interface represents a mounted volume as follows:
VDISK-MountPoint-n
n represents the configuration number of a mount point in a specific system. The actual mount point paths will be saved in the Registry Edit.
VDisk_MountPoint_001
The path-style representation of a mounted volume can appear in any part of the SnapManager user interface that refers to LUNs accessed by SnapManager:
LUNs that are referenced more than once: If the LUN is configured with multiple references, each such LUN reference is listed with a label that lists any other references to the same LUN.
For example, suppose the drive letter M: and the mount point C:\Mnt_Pnt\ reference the same LUN. In this case, the Disk List selection contains two entries for one LUN:
LUN M: <C:\Mnt_Pnt\>
LUN C:\Mnt_Pnt\ <M>
Swap LUN using reference mount point: Suppose a database resides in LUN M, create a reference C:\Mnt_Pnt1\db to it using the SnapDrive. Use the Configuration Wizard to detach the database from the original location LUN M and attach it to the reference C:\Mnt_Pnt1\db without copying or moving the database files. This operation is called LUN swapping.
SMSQL configuration wizard lists all references to the same LUN. In this case, the Disk List selection contains two entries:
LUN M: <C:\Mnt_Pnt1\db\>
LUN C:\Mnt_Pnt1\db\ <M>
The database is now attached to the C:\Mnt_Pnt1\db instead of M.
LUNs that have mounted volumes: If SnapManager accesses a LUN with a volume that is referenced by a mount point, that LUN is listed with a label that indicates this.
For example, suppose the drive letter J: references a LUN that hosts a mount point. In this case, the Disk List selection lists that LUN as follows:
LUN J: (MPRoot)
The Configuration Wizard does not allow you to store SQL database files on LUNs that host NTFS volume mount points.
You can access this setting from the following locations within the SnapManager user interface:
For more information, see Appendix C, Using the Access LUN in Snapshot tab.
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Part No. 215-01752_A0
File: vmp3.htm
Last updated: 01-Sep-2006 07:41:10