.TH mmrpldisk 02/16/06
mmrpldisk Command
.SH "Name"
.PP
\fBmmrpldisk\fR - Replaces the specified disk.
.SH "Synopsis"
.PP
\fBmmrpldisk\fR \fIDevice DiskName\fR {\fIDiskDesc\fR |
\fB-F\fR \fIDescFile\fR} [\fB-v\fR \fB\fIyes\fR\fR |
\fBno\fR] [\fB-N\fR
{\fINode\fR[,\fINode\fR...] |
\fINodeFile\fR | \fINodeClass\fR}]
.SH "Description"
.PP
Use the \fBmmrpldisk\fR command to replace an existing disk in the GPFS
file system with a new one. All data on the old disk is migrated to the
new one.
.PP
To replace disks in a GPFS file system, you must first decide if you
will:
.RS +3
.HP 3
1. 
Create new disks using the
\fBmmcrnsd\fR
command. 
.sp
Use the rewritten disk descriptor file produced by the \fBmmcrnsd\fR command or create a new disk
descriptor. When using the rewritten file, the \fIDisk Usage\fR and
\fIFailure Group\fR specifications remain the same as specified on the \fBmmcrnsd\fR command.
.HP 3
2. Select disks no longer in use in any file system. Issue the \fBmmlsnsd -F\fR command to display the available
disks.
.RE
.PP
The disk may then be used to replace a disk in the file system using the \fBmmrpldisk\fR command.
.PP
\fBNotes: \fR
.RS +3
.sp
.HP 3
1. You cannot replace a disk when it is the only remaining disk in the file
system.
.sp
.HP 3
2. Under no circumstances should you replace a stopped disk. You need
to start a stopped disk before replacing it. If a disk cannot be
started, you must delete it using the
\fBmmdeldisk\fR
command. See the
\fIGeneral Parallel File
System: Problem Determination Guide\fR and search for \fIDisk
media failure\fR.
.sp
.HP 3
3. The file system need not be unmounted before the \fBmmrpldisk\fR
command can be run.
.sp
.HP 3
4. 
I/O operations from SANergy clients must terminate before using the
\fBmmrpldisk\fR command. If not, the client applications receive an
error.
.RE
.PP
\fBResults\fR
.PP
Upon successful completion of the \fBmmrpldisk\fR command, the disk is
replaced in the file system and data is copied to the new disk without
restriping.
.SH "Parameters"
.PP
.RS +3
\fB\fIDevice\fR
\fR
.RE
.RS +9
The device name of the file system where the disk is to be
replaced. File system names need not be fully-qualified.
\fBfs0\fR is as acceptable as \fB/dev/fs0\fR. 
.PP
This must be the first parameter.
.RE
.PP
.RS +3
\fB\fIDisk Name\fR
\fR
.RE
.RS +9
The name of the disk to be replaced, which was previously passed to the \fBmmcrfs\fR,
\fBmmadddisk\fR,
or \fBmmrpldisk\fR commands. You can display the entire list of disk
names by issuing the
\fBmmlsdisk\fR command.
.RE
.PP
.RS +3
\fB\fIDiskDesc\fR
\fR
.RE
.RS +9
A descriptor for the replacement disk.
.RE
.PP
.RS +3
\fB-F \fIDescFile\fR
\fR
.RE
.RS +9
Specifies a file containing the disk descriptor for the replacement
disk.
.PP
The disk descriptor must be specified in the form (second, third,
and sixth fields reserved):
.sp
.nf
DiskName:::DiskUsage:FailureGroup:::
.fi
.sp
.PP
.RS +3
\fB\fIDiskName\fR
\fR
.RE
.RS +9
.PP
You must specify the name of the NSD previously created by the \fBmmcrnsd\fR command. For a list of available
disks, issue the
\fBmmlsnsd -F\fR command.
.RE
.PP
.RS +3
\fB\fIDisk Usage\fR
\fR
.RE
.RS +9
Specify a disk usage or inherit the disk usage of the disk being
replaced: 
.PP
.RS +3
\fBdataAndMetadata
\fR
.RE
.RS +9
Indicates that the disk contains both data and metadata. This is
the default.
.RE
.PP
.RS +3
\fBdataOnly
\fR
.RE
.RS +9
Indicates that the disk contains data and does not contain
metadata.
.RE
.PP
.RS +3
\fBmetadataOnly
\fR
.RE
.RS +9
Indicates that the disk contains metadata and does not contain
data.
.RE
.PP
.RS +3
\fBdescOnly
\fR
.RE
.RS +9
Indicates that the disk contains no data and no file metadata. Such
a disk is used solely to keep a copy of the file system descriptor, and can be
used as a third failure group in certain disaster recovery
configurations. For more information, see
\fIGeneral Parallel File System: Advanced
Administration\fR and search on \fISynchronous mirroring utilizing
GPFS replication\fR.
.RE
.RE
.PP
.RS +3
\fB\fIFailure Group\fR
\fR
.RE
.RS +9
A number identifying the failure group to which this disk belongs.
You can specify any value from -1 (where -1 indicates that the disk has no
point of failure in common with any other disk) to 4000. If you do not
specify a failure group, the new disk inherits the failure group of the disk
being replaced.
.RE
.RS +3
\fBNote:\fR
.RE
.RS +9
While it is not absolutely necessary to specify the same disk descriptor
parameters for the new disk as the old disk, it is suggested you do so.
If the new disk is equivalent in size as the old disk, and if the
\fIDiskUsage\fR and \fIFailureGroup\fR parameters are the same, the data
and metadata can be completely migrated from the old disk to the new
disk. A disk replacement in this manner allows the file system to
maintain its current data and metadata balance.
.PP
If the new disk has a different size, \fIDiskUsage\fR parameter, or
\fIFailureGroup\fR parameter, the operation may leave the file system
unbalanced and require a restripe. Additionally, a change in size or
the \fIDiskUsage\fR parameter may cause the operation to fail since other
disks in the file system may not have sufficient space to absorb more data or
metadata. In this case you must first use the \fBmmadddisk\fR command to add the new disk, the \fBmmdeldisk\fR command to delete the old disk, and
finally the
\fBmmrestripefs\fR command to rebalance
the file system.
.RE
.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 migration of data from the old
to the new disk. 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-v {\fB\fIyes\fR\fR | no}
\fR
.RE
.RS +9
Verify that specified disks do not belong to an existing file
system. The default is \fB-v yes\fR. Specify \fB-v no\fR
only when you want to reuse disks that are no longer needed for an existing
file system. If the command is interrupted for any reason, you must use
the \fB-v no\fR option on the next invocation of the command.
.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 \fBmmrpldisk\fR command.
.PP
You may issue the \fBmmrpldisk\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 replace disk \fBgpfs10nsd\fR in \fBfs3\fR with a new disk,
\fBgpfs12nsd\fR allowing the disk usage and failure group parameters to
default to the corresponding values of \fBgpfs10nsd\fR, and have only nodes
\fBk145n01, k145n03, and k145n05\fR participate in the migration of the
data, issue this command:
.sp
.nf
mmrpldisk fs3 gpfs10nsd gpfs12nsd -N k145n01,k145n03,k145n05
.fi
.sp
.PP
The system displays information similar to:
.sp
.nf
Replacing  ...
GPFS: 6027-531 The following disks of fs3 will be formatted on\ 
node k145n03  gpfs12nsd: size 4390912 KB
Extending Allocation Map
GPFS: 6027-1503 Completed adding disks to file system fs3.
GPFS: 6027-589 Scanning file system metadata, phase 1 ...\ 
  77 % complete on Wed Jul 12 17:33:58 2000
 100 % complete on Wed Jul 12 17:33:59 2000
GPFS: 6027-552 Scan completed successfully.
GPFS: 6027-589 Scanning file system metadata, phase 2 ...\ 
GPFS: 6027-552 Scan completed successfully.
GPFS: 6027-589 Scanning file system metadata, phase 3 ...\ 
GPFS: 6027-552 Scan completed successfully.
GPFS: 6027-565 Scanning user file metadata ...
   1 % complete on Wed Jul 12 17:34:12 2000
 100 % complete on Wed Jul 12 17:34:15 2000
GPFS: 6027-552 Scan completed successfully.
Done
mmrpldisk: 6027-1371 Propagating the changes to all affected
                     nodes. This is an asynchronous process.
.fi
.sp
.SH "See also"
.PP
mmadddisk Command
.PP
mmchdisk Command
.PP
mmcrnsd Command
.PP
mmlsdisk Command
.PP
mmlsnsd Command
.PP
mmrestripefs Command
.SH "Location"
.PP
\fB/usr/lpp/mmfs/bin\fR
.PP