How is SAN storage dynamically configured in a Microsoft environment? How does the OS attach the storage once it is zoned and reachable by that MS server?
(Continued from Part Two) Under Windows 2000, there is a new Disk Administrator called LDM (or Logical Disk Administrator). This Volume Manager, like the VERITAS Volume Manager, has the construct called "Dynamic Disks." If this construct is used (instead of the "basic disks") concept, the Volume and associated file system can grow on line. This works as follows:
* One uses the Dynamic Disk partitioning method to encapsulate the LUN from the RAID system.
* One then enlarges the LUN on the storage system.
* One then "rescans" the bus, using LDM or the VERITAS Volume Manager.
* If there is a direct match between the Dynamic Disk partition and the NTFS File system, then both will grow in synchrony.
There is a version of the VERITAS Volume Manager for NT 4 that also supports Dynamic Disks.
Due to other constraints NTFS under NT 4.0, a reboot is required to see the larger LUN and grow the file system at the same time.
VERITAS Volume Manager has another feature useful in a Windows 2000 SAN environment which is not present in LDM nor in VERITAS Volume Manager NT 4.0. Storage can be segmented so that it is not immediately brought on line at boot time, but can be imported later on in the boot cycle using CLI or manual entry. The user does this by encapsulating the specified storage as "clustered disk groups". This makes the system easier to manage and ensure the right servers only see the storage associated with them.
Special thanks to Bruce for adding to the earlier response!
This was first published in March 2001