Administrator Guide

NOTE: To ensure that the migrating disk groups and virtual disks are correctly recognized when the target storage array
has an existing physical disk, use hot virtual disk migration.
When attempting virtual disk migration, follow these recommendations:
• Moving physical disks to the destination array for migration—When inserting physical disks into the destination storage array during
hot virtual disk migration, wait for the inserted physical disk to be displayed in the MD Storage Manager, or wait for 30 seconds
(whichever occurs first), before inserting the next physical disk.
NOTE: Without the interval between physical disk insertions, the storage array may become unstable and
manageability may be temporarily lost.
• Migrating virtual disks from multiple storage arrays into a single storage array—When migrating virtual disks from multiple or different
storage arrays into a single destination storage array, move all the physical disks from the same storage array as a set into the new
destination storage array. Ensure that all the physical disks from a storage array are migrated to the destination storage array before
starting migration from the next storage array.
NOTE: If the physical disk modules are not moved as a set to the destination storage array, the newly relocated disk
groups may not be accessible.
• Migrating virtual disks to a storage array with no existing physical disks—Turn off the destination storage array, when migrating disk
groups or a complete set of physical disks from a storage array to another storage array that has no existing physical disks. After the
destination storage array has been turned on and has successfully recognized the newly migrated physical disks, migration operations
can continue.
NOTE: Disk groups from multiple storage arrays must not be migrated at the same time to a storage array that has
no existing physical disks. Use cold virtual disk migration for the disk groups from one storage array.
• Enabling premium features before migration—Before migrating disk groups and virtual disks, enable the required premium features on
the destination storage array. If a disk group is migrated from a storage array that has a premium feature enabled and the destination
array does not have this feature enabled, an Out of Compliance error message can be generated.
Disk roaming
You can move physical disks within an array. The RAID controller module automatically recognizes the relocated physical disks and logically
places them in the proper virtual disks that are part of the disk group. Disk roaming is permitted when the RAID controller module is either
online or powered off.
NOTE: The disk group must be exported before moving the physical disks.
Host server-to-virtual disk mapping
The host server attached to a storage array accesses various virtual disks on the storage array through its host ports. Specific virtual disk-
to-LUN mappings to an individual host server can be defined. In addition, the host server can be part of a host group that shares access to
one or more virtual disks. You can manually configure a host server-to-virtual disk mapping. When you configure host server-to-virtual disk
mapping, consider these guidelines:
• You can define one host server-to-virtual disk mapping for each virtual disk in the storage array.
• Host server-to-virtual disk mappings are shared between RAID controller modules in the storage array.
• A unique LUN must be used by a host group or host server to access a virtual disk.
• Not every operating system has the same number of LUNs available for use.
Host types
A host server is a server that accesses a storage array. Host servers are mapped to the virtual disks and use one or more iSCSI initiator
ports. Host servers have the following attributes:
• Host name — A name that uniquely identifies the host server.
• Host group (used in Cluster solutions only) — Two or more host servers associated together to share access to the same virtual disks.
NOTE:
This host group is a logical entity you can create in the MD Storage Manager. All host servers in a host group
must be running the same operating system.
• Host type — The operating system running on the host server.
About your MD Series storage array
23