GPFS: Administration and Programming Reference - IRA Home

network connections, but data sent over the connection is not protected. Before setting cipherList for
the first time, you must establish a public/private key pair for the cluster by using the mmauth genkey
new command.
See the Frequently Asked Questions at: publib.boulder.ibm.com/infocenter/ clresctr/topic/
com.ibm.cluster.gpfs.doc/gpfs_faqs/gpfsclustersfaq.html for a list of the ciphers supported by GPFS.
dataStructureDump
Specifies a path for the storage of dumps. The default is to store dumps in /tmp/mmfs. Specify no to
not store dumps.
It is suggested that you create a directory for the placement of certain problem determination
information. This can be a symbolic link to another location if more space can be found there. Do not
place it in a GPFS file system, because it might not be available if GPFS fails. If a problem occurs,
GPFS may write 200 MB or more of problem determination data into the directory. These files must be
manually removed when problem determination is complete. This should be done promptly so that a
NOSPACE condition is not encountered if another failure occurs.
designation
Specifies a ’-’ separated list of node roles.
mmchconfig Command
v manager or client - Indicates whether a node is part of the pool of nodes from which configuration
managers, file system managers, and token managers are selected.
v quorum or nonquorum - Indicates whether a node is to be counted as a quorum node.
GPFS must be stopped on any quorum node that is being changed to nonquorum. GPFS does not
have to stopped when the designation changes from nonquorum to quorum.
For more information on the roles of a node as the file system manager, see the General Parallel File
System: Concepts, Planning, and Installation Guide and search for file system manager.
For more information on explicit quorum node designation, see the General Parallel File System:
Concepts, Planning, and Installation Guide and search for designating quorum nodes.
distributedTokenServer
Specifies whether the token server role for a file system should be limited to only the file system
manager node (no), or distributed to other nodes for better file system performance (yes). The default
is yes.
Using multiple token servers requires designating the nodes that should serve tokens as manager
nodes (manager keyword in the mmcrcluster node list or mmchconfig designation=... commands). If
no manager nodes are designated, the node chosen as file system manager will act as the only token
server, regardless of the setting of the distributedTokenServer parameter.
The maxFilesToCache and maxStatCache parameters are indirectly affected by the
distributedTokenServer parameter, because distributing the tokens across multiple nodes may allow
keeping more tokens than without this feature. See General Parallel File System: Concepts, Planning,
and Installation Guide and search on The GPFS token system’s affect on cache settings.
dmapiEventTimeout
Controls the blocking of file operation threads of NFS, while in the kernel waiting for the handling of a
DMAPI synchronous event. The parameter value is the maximum time, in milliseconds, the thread will
block. When this time expires, the file operation returns ENOTREADY, and the event continues
asynchronously. The NFS server is expected to repeatedly retry the operation, which eventually will find
the response of the original event and continue. This mechanism applies only to read, write, and
truncate event types, and only when such events come from NFS server threads. The timeout value is
given in milliseconds. The value 0 indicates immediate timeout (fully asynchronous event). A value
greater than or equal to 86400000 (which is 24 hours) is considered infinity (no timeout, fully
synchronous event). The default value is 86400000.
For further information regarding DMAPI for GPFS, see General Parallel File System: Data
Management API Guide.
Chapter 8. GPFS commands 89