IBM Storage Scale System 6000 Service Manual page 78

node number
A number that is generated and maintained by ESS as the cluster is created, and as nodes are added
to or deleted from the cluster.
node quorum
The minimum number of nodes that must be running in order for the daemon to start.
node quorum with tiebreaker disks
A form of quorum that allows ESS to run with as little as one quorum node available, as long as there
is access to a majority of the quorum disks.
non-quorum node
A node in a cluster that is not counted for the purposes of quorum determination.
O
OFED
See OpenFabrics Enterprise Distribution (OFED).
OpenFabrics Enterprise Distribution (OFED)
An open-source software stack includes software drivers, core kernel code, middleware, and user-
level interfaces.
P
pdisk
A physical disk.
PortFast
A Cisco network function that can be configured to resolve any problems that could be caused by the
amount of time STP takes to transition ports to the Forwarding state.
R
RAID
See redundant array of independent disks (RAID).
RDMA
See remote direct memory access (RDMA).
redundant array of independent disks (RAID)
A collection of two or more disk physical drives that present to the host an image of one or more
logical disk drives. In the event of a single physical device failure, the data can be read or regenerated
from the other disk drives in the array due to data redundancy.
recovery
The process of restoring access to file system data when a failure has occurred. Recovery can involve
reconstructing data or providing alternative routing through a different server.
recovery group (RG)
A collection of disks that is set up by ESS, in which each disk is connected physically to two servers: a
primary server and a backup server.
remote direct memory access (RDMA)
A direct memory access from the memory of one computer into that of another without involving
either one's operating system. This permits high-throughput, low-latency networking, which is
especially useful in massively parallel computer clusters.
RGD
See recovery group data (RGD).
remote key management server (RKM server)
A server that is used to store master encryption keys.
RG
See recovery group (RG).
66 IBM Storage Scale System 6000: Service Guide