Dell POWERVAULT MD3620I - Manual (Page 121)

Configuration: Disk Groups and Virtual Disks 121
The corresponding dynamic cache read prefetch setting and segment size
values that are typically well suited for the selected virtual disk I/O
characteristic type are populated in the Dynamic cache read prefetch
field and the Segment size field.
NOTE: If you selected the Custom option, select your preferred dynamic
cache read prefetch setting (enabled/disabled) and segment size (8 KB to
512 KB).
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 is security enabled, the physical disk requires the correct
security key from a RAID controller module to read or write the data. All of
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