Dot Hill Systems AssuredSAN 4544, Setup Manual

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28 Installing the enclosures
While replacing or installing FDE-capable disk drive modules, consider the following:
• If you are installing FDE-capable disk drive modules that do not have keys into a secure system, the
system will automatically secure the disks after installation. Your system will associate its existing key
with the disks, and you can transparently use the newly-secured disks.
• If the FDE-capable disk drive modules originate from another secure system, and contain that system’s
key, the new disks will have the Secure, Locked status. The data will be unavailable until you enter the
passphrase for the other system to import its key. Your system will then recognize the metadata of the
vdisks and incorporate it. The disks will have the status of Secure, Unlocked and their contents will be
available:
• To view the FDE status of disks, use RAIDar or the
show fde-state
CLI command.
• To import a key and incorporate the foreign disks, use RAIDar or the
set fde-import-key
CLI
command.
NOTE: If the FDE-capable disks contain multiple keys, you will need to perform the key importing
process for each key to make the content associated with each key become available.
• If you do not want to retain the disks’ data, you can repurpose the disks. Repurposing disks deletes all
disk data, including lock keys, and associates the current system’s lock key with the disks.
To repurpose disks, use RAIDar or the
set disk
CLI command.
• You need not secure your system to use FDE-capable disks. If you install all FDE-capable disks into a
system that is not secure, they will function exactly like disks that do not support FDE. As such, the data
they contain will not be encrypted. If you decide later that you want to secure the system, all of the disks
must be FDE-capable.
• If you install a disk module that does not support FDE into a secure system, the disk will have the
Unusable status and will be unavailable for use.
• If you are re-installing your FDE-capable disk drive modules as part of the process to replace the
chassis-and-midplane FRU, you must insert the original disks and re-enter their FDE passprhase (see the
AssuredSAN Ultra48 Series FRU Installation and Replacement Guide for more information).
Connecting the controller enclosure and drive enclosures
AssuredSAN Ultra48 Series controller enclosures—available in 48-drive (2.5") 2U chassis—support up to
four enclosures (including the controller enclosure), or a maximum of 192 disk drives. The Ultra48 Series
enclosures support both straight-through and reverse SAS cabling. Reverse cabling allows any drive
enclosure to fail—or be removed—while maintaining access to other enclosures. Fault tolerance and
performance requirements determine whether to optimize the configuration for high availability or high
performance when cabling. AssuredSAN Ultra48 Series controller modules support both 3-Gbps and
6-Gbps internal disk drive speeds together with 3-Gbps and 6-Gbps expander link speeds.
CAUTION: Some 6-Gbps disks might not consistently support a 6-Gbps transfer rate. If this happens, the
system automatically adjusts transfers to those disks to 3 Gbps, increasing reliability and reducing error
messages with little impact on system performance. This rate adjustment persists until the controller is
restarted or power-cycled.
Cabling diagrams in this section show fault-tolerant cabling patterns. Controller and expansion modules
are identified by
<enclosure-ID><controller-ID>
. When connecting multiple drive enclosures, use
reverse cabling to ensure the highest level of fault tolerance, enabling controllers to access remaining drive
enclosures if a drive enclosure fails.
For example, the illustration on the left in Figure 20 on page 30 shows reverse cabling, wherein
controller 0A (i.e., enclosure-ID = 0; controller-ID = Able) is connected to expansion module 1A, with a
chain of connections cascading down (blue). Controller 0B is connected to the lower expansion
module (B) of the last drive enclosure in the chain, with connections moving in the opposite direction
(green). Several cabling examples are provided on the following pages.