.TH mmdeldisk 03/31/06
mmdeldisk Command
.SH "Name"
.PP
\fBmmdeldisk\fR - Deletes disks from a GPFS file system.
.SH "Synopsis"
.PP
\fBmmdeldisk\fR \fIDevice\fR
{"\fIDiskDesc\fR[;\fIDiskDesc\fR...]"
| \fB-F\fR \fIDescFile\fR} [\fB-a\fR]
[\fB-c\fR] [\fB-r\fR] [\fB-N\fR
{\fINode\fR[,\fINode\fR...] | \fINodeFile\fR | \fINodeClass\fR}]
.SH "Description"
.PP
The \fBmmdeldisk\fR command migrates all data that would otherwise be
lost to the remaining disks in the file system. It then removes the
disks from the file system descriptor and optionally rebalances the file
system after removing the disks.
.PP
Run the \fBmmdeldisk\fR command when system demand is low.
.PP
I/O operations from SANergy clients must terminate before using the
\fBmmdeldisk\fR command. If not, the client applications receive an
error.
.PP
If a replacement for a failing disk is available, use the \fBmmrpldisk\fR command in order to keep the file system
balanced. Otherwise, use one of these procedures to delete a
disk:
.RS +3
.HP 3
\(bu If the disk is not failing and GPFS can still read from it:
.RS +3
.HP 3
1. Suspend the disk
.HP 3
2. Restripe to rebalance all data onto other disks
.HP 3
3. Delete the disk
.RE
.HP 3
\(bu If the disk is permanently damaged and the file system is
replicated:
.RS +3
.HP 3
1. Suspend and stop the disk.
.HP 3
2. restripe and restore replication for the file system, if possible.
.HP 3
3. Delete the disk from the file system.
.RE
.HP 3
\(bu If the disk is permanently damaged and the file system is not replicated,
or if the \fBmmdeldisk\fR command repeatedly fails, see the
\fIGeneral Parallel File System: Problem
Determination Guide\fR and search for \fIDisk media
failure\fR.
.RE
.PP
If the last disk in a storage pool is deleted, the storage pool is
deleted. The \fBmmdeldisk\fR command is not permitted to delete the
\fBsystem\fR storage pool. A storage pool must be empty in order for
it to be deleted.
.PP
\fBResults\fR
.PP
Upon successful completion of the \fBmmdeldisk\fR command, these tasks
are completed:
.RS +3
.HP 3
\(bu Data that has not been replicated from the target disks is migrated to
other disks in the file system.
.HP 3
\(bu Remaining disks are rebalanced, if specified.
.RE
.SH "Parameters"
.PP
.RS +3
\fB\fIDevice\fR
\fR
.RE
.RS +9
The device name of the file system to delete the disks from. File
system names need not be fully-qualified. \fBfs0\fR is as acceptable
as \fB/dev/fs0\fR. This must be the first parameter.
.RE
.PP
.RS +3
\fB"\fIDiskDesc\fR[;\fIDiskDesc\fR...]"
.PP
\fR
.RE
.RS +9
The disk descriptors of the disks to be deleted from the file
system. If there is more than one disk to be deleted, delimit each
descriptor with a semicolon (;) and enclose the list of disk descriptors
in quotation marks.
.RE
.PP
.RS +3
\fB-F \fIDescFile\fR
\fR
.RE
.RS +9
A file that contains a list of disk descriptors, one per line representing
disks, to be deleted.
.RE
.PP
.RS +3
\fB-N {\fINode\fR[,\fINode\fR...] |
\fINodeFile\fR | \fINodeClass\fR }
\fR
.RE
.RS +9
Specify the nodes that participate in the restripe of the file system
after the specified disks have been removed. This command supports all
defined node classes. The default is \fBall\fR (all nodes in the
GPFS cluster will participate in the restripe of the file system).
.PP
For information on how to specify node names, see \fISpecifying nodes as input to GPFS commands\fR
in \fIGPFS: Administration and Programming Reference\fR.
.RE
.SH "Options"
.PP
.RS +3
\fB-a 
\fR
.RE
.RS +9
Specifies that the \fBmmdeldisk\fR command \fInot\fR wait for
rebalancing to complete before returning. When this flag is specified,
the \fBmmdeldisk\fR command runs asynchronously and returns after the file
system descriptor is updated and the rebalancing scan is started, but it does
not wait for rebalancing to finish. If no rebalancing is requested
(\fB-r \fR option is not specified), this option has no effect.
.RE
.PP
.RS +3
\fB-c
\fR
.RE
.RS +9
Specifies that processing continues even in the event that unreadable data
exists on the disks being deleted. Data that has not been replicated is
lost. Replicated data is not lost as long as the disks containing the
replication are accessible.
.RE
.PP
.RS +3
\fB-r 
\fR
.RE
.RS +9
Rebalance all existing files in the file system to make more efficient use
of the remaining disks.
.RS +3
\fBNote:\fR
.RE
.RS +9
Rebalancing of files is an I/O intensive and time consuming operation, and is
important only for file systems with large files that are mostly
invariant. In many cases, normal file update and creation will
rebalance your file system over time, without the cost of the
rebalancing.
.RE
.RE
.SH "Exit status"
.PP
.PP
.RS +3
\fB0
\fR
.RE
.RS +9
Successful completion.
.RE
.PP
.RS +3
\fBnonzero
\fR
.RE
.RS +9
A failure has occurred.
.RE
.SH "Security"
.PP
You must have root authority to run the \fBmmdeldisk\fR command.
.PP
You may issue the \fBmmdeldisk\fR command from any node in the GPFS
cluster.
.PP
When using the \fBrcp\fR and \fBrsh\fR commands for remote
communication, a properly configured \fB.rhosts\fR file must exist
in the root user's home directory on each node in the GPFS
cluster. If you have designated the use of a different remote
communication program on either the
\fBmmcrcluster\fR
or the
\fBmmchcluster\fR command, you must
ensure:
.RS +3
.HP 3
1. Proper authorization is granted to all nodes in the GPFS cluster.
.HP 3
2. The nodes in the GPFS cluster can communicate without the use of a
password, and without any extraneous messages.
.RE
.SH "Examples"
.PP
To delete \fBgpfs2nsd\fR and \fBgpfs3nsd\fR from file system
\fBfs0\fR and rebalance the files across the remaining disks, issue this
command:
.sp
.nf
mmdeldisk fs0 "gpfs2nsd;gpfs3nsd" -r
.fi
.sp
.PP
The system displays information similar to:
.sp
.nf
Dleting disks ...
Scanning 'system' storage pool
Scanning file system metadata, phase 1 ...\ 
Scan completed successfully.
Scanning file system metadata, phase 2 ...\ 
Scan completed successfully.
Scanning file system metadata, phase 3 ...\ 
Scan completed successfully.
Scanning file system metadata, phase 4 ...\ 
Scan completed successfully.
Scanning user file metadata ...
   2 %  complete on Tue Feb 14 14:45:18 2006
   3 %  complete on Tue Feb 14 14:45:21 2006
   9 %  complete on Tue Feb 14 14:45:24 2006
  18 %  complete on Tue Feb 14 14:45:27 2006
  27 %  complete on Tue Feb 14 14:45:35 2006
  28 %  complete on Tue Feb 14 14:45:39 2006
  29 %  complete on Tue Feb 14 14:45:43 2006
  30 %  complete on Tue Feb 14 14:45:52 2006
  34 %  complete on Tue Feb 14 14:46:04 2006
  37 %  complete on Tue Feb 14 14:46:18 2006
  45 %  complete on Tue Feb 14 14:46:22 2006
  51 %  complete on Tue Feb 14 14:46:26 2006
  94 %  complete on Tue Feb 14 14:46:29 2006
 100 %  complete on Tue Feb 14 14:46:32 2006
Scan completed successfully.
tsdeldisk64 completed.
mmdeldisk: Propagating the cluster configuration data to all
  affected nodes.  This is an asynchronous process.
.fi
.sp
.SH "See also"
.PP
mmadddisk Command
.PP
mmchdisk Command
.PP
mmlsdisk Command
.PP
mmrpldisk Command
.SH "Location"
.PP
\fB/usr/lpp/mmfs/bin\fR
.PP