Configuration: Disk Groups and Virtual Disks 113
NOTE: If you selected the Custom option, select your preferred dynamic
cache read prefetch setting (enabled/disabled) and segment size (8KB to
512KB).
2
Click
OK
.

Choosing an Appropriate Physical Disk Type

You can create disk groups and virtual disks in the storage array. You must
select the capacity that you want to allocate for the virtual disk from either
unconfigured capacity or free capacity available in the storage array. Then you
define basic and optional advanced parameters for the virtual disk.
With the advent of different physical disk technologies, it is now possible to
mix physical disks with different media types and different interface types
within a single storage array. In this release of MDSM, the following media
types are supported:
• Hard physical disk
• Solid State Disk (SSD)

Physical Disk Security with Self Encrypting Disk

Self encrypting disk (SED) technology prevents unauthorized access to the
data on a physical disk that is physically removed from the storage array. The
storage array has a security key. Self encrypting disks provide access to data
only through an array that has the correct security key.
The self encrypting disk or a security capable physical disk encrypts data
during writes and decrypts data during reads. For more information, see the
PowerVault Modular Disk Storage Manager online help topics.
You can create a secure disk group from security capable physical disks. When
you create a secure disk group from security capable physical disks, the
physical disks in that disk group become security enabled. When a security
capable physical disk has been security enabled, the physical disk requires the
correct security key from a RAID controller module to read or write the data.
All of the physical disks and RAID controller modules in a storage array share
the same security key. The shared security key provides read and write access
to the physical disks, while the physical disk encryption key on each physical
disk is used to encrypt the data. A security capable physical disk works like any
other physical disk until it is security enabled.
book.book Page 113 Wednesday, May 26, 2010 2:14 PM