IBM Storage Scale System 6000 Service Manual page 74

DCM
See drawer control module (DCM).
declustered array (DA)
A disjoint subset of the pdisks in a recovery group.
dependent fileset
A fileset that shares the inode space of an existing independent fileset.
DFM
See direct FSP management (DFM).
DHCP
See Dynamic Host Configuration Protocol (DHCP).
drawer control module (DCM)
Essentially, a SAS expander on a storage enclosure drawer.
Dynamic Host Configuration Protocol (DHCP)
A standardized network protocol that is used on IP networks to dynamically distribute such network
configuration parameters as IP addresses for interfaces and services.
E
Elastic Storage System (ESS)
See IBM Storage Scale System.
EMS virtual machine (EMSVM)
Virtual machine of an IBM Storage Scale System management server. See MS management server and
IBM Storage Scale System.
ESS management server (EMS)
See management server and IBM Storage Scale System.
encryption key
A mathematical value that allows components to verify that they are in communication with the
expected server. Encryption keys are based on a public or private key pair that is created during the
installation process. See also file encryption key (FEK), master encryption key (MEK).
ESS
See Elastic Storage System (ESS).
environmental service module (ESM)
Essentially, a SAS expander that attaches to the storage enclosure drives. In the case of multiple
drawers in a storage enclosure, the ESM attaches to drawer control modules.
ESM
See environmental service module (ESM).
F
failback
Cluster recovery from failover following repair. See also failover.
failover
(1) The assumption of file system duties by another node when a node fails. (2) The process of
transferring all control of the ESS to a single cluster in the ESS when the other clusters in the ESS fails.
See also cluster. (3) The routing of all transactions to a second controller when the first controller fails.
See also cluster.
failure group
A collection of disks that share common access paths or adapter connection, and could all become
unavailable through a single hardware failure.
FEK
See file encryption key (FEK).
62 IBM Storage Scale System 6000: Service Guide