source: gpfs_3.1_ker2.6.20/share/man/man8/mmfsck.8 @ 32

.TH mmfsck 02/16/06

mmfsck Command

.SH "Name"

.PP

\fBmmfsck\fR - Checks and repairs a GPFS file system.

.SH "Synopsis"

.PP

\fBmmfsck\fR \fIDevice\fR [\fB-n\fR |

\fB-y\fR] [\fB-c\fR | \fB-o\fR] [\fB-t\fR

\fIDirectory\fR] [\fB-v\fR | \fB-V\fR]

[\fB-N\fR

{\fINode\fR[,\fINode\fR...] |

\fINodeFile\fR | \fINodeClass\fR}]

.PP

The file system must be unmounted before you can run the \fBmmfsck\fR

command with any option other than \fB-o\fR.

.PP

\fBDescription\fR

.PP

The \fBmmfsck\fR command in offline mode is intended to be used only in

situations where there have been disk or communications failures that have

caused \fBMMFS_FSSTRUCT\fR error log entries to be issued, or where it is

known that disks have been forcibly removed or otherwise permanently

unavailable for use in the file system, and other unexpected symptoms are seen

by users. In general it is unnecessary to run \fBmmfsck\fR in

offline mode unless under the direction of the IBM Support Center.

.PP

If neither the \fB-n\fR nor \fB-y\fR flag is specified, the

\fBmmfsck\fR command runs interactively prompting you for permission to

repair each consistency error as reported. It is suggested that in all

but the most severely damaged file systems, you run the \fBmmfsck\fR

command interactively (the default).

.PP

The occurrence of I/O errors, or the appearance of a message telling you to

run the \fBmmfsck\fR command, may indicate file system

inconsistencies. If either situation occurs, use the \fBmmfsck\fR

command to check file system consistency and interactively repair the file

system.

.PP

The \fBmmfsck\fR command checks for these inconsistencies:

.RS +3

.HP 3

\(bu Blocks marked allocated that do not belong to any file. The

corrective action is to mark the block free in the allocation map.

.HP 3

\(bu 

Files for which an inode is allocated and no directory entry exists (orphaned

files). The corrective action is to create directory entries for these

files in a \fBlost+found\fR subdirectory at the root of this file

system. The index number of the inode is assigned as the name.

If you do not allow the \fBmmfsck\fR command to reattach an orphaned file,

it asks for permission to delete the file.

.HP 3

\(bu Directory entries pointing to an inode that is not allocated. The

corrective action is to remove the directory entry.

.HP 3

\(bu Incorrectly formed directory entries. A directory file contains the

inode number and the generation number of the file to which it refers.

When the generation number in the directory does not match the generation

number stored in the file's inode, the corrective action is to remove the

directory entry.

.HP 3

\(bu Incorrect link counts on files and directories. The corrective

action is to update them with accurate counts.

.HP 3

\(bu Cycles in the directory structure. The corrective action is to

break any detected cycles. If the cycle was a disconnected cycle, the

new top level directory is moved to the \fBlost+found\fR directory.

.HP 3

\(bu Invalid policy files. The corrective action is to delete the

file.

.HP 3

\(bu The \fBmmfsck\fR command checks that each fileset has a root

directory, that each linked fileset has exactly one valid junction pointing to

it, and that no junctions point to unlinked filesets. In addition, the

metadata file of the filesets are checked for consistency with respect to the

inode of the file system.

.RE

.PP

If you are repairing a file system due to node failure and the file system

has quotas enabled, it is suggested that you run the \fBmmcheckquota\fR command to recreate the quota

files.

.PP

Indications leading you to the conclusion that you should run the

\fBmmfsck\fR command include:

.RS +3

.HP 3

1. 

An \fBMMFS_FSSTRUCT\fR along with an \fBMMFS_SYSTEM_UNMOUNT\fR error log

entry on any node indicating some critical piece of the file system is

inconsistent.

.HP 3

2. Disk media failures

.HP 3

3. Partial disk failure

.HP 3

4. \fBEVALIDATE=214\fR, Invalid checksum or other consistency check

failure on a disk data structure, reported in error logs or returned to an

application.

.RE

.PP

For further information on recovery actions and how to contact the IBM

Support Center, see the

\fIGeneral Parallel File

System: Problem Determination Guide\fR.

.PP

If you are running the online \fBmmfsck\fR command to free allocated

blocks that do not belong to any files, plan to make file system repairs when

system demand is low. This is an I/O intensive activity and it can

affect system performance.

.PP

\fBResults\fR

.PP

If the file system is inconsistent, the \fBmmfsck\fR command displays

information about the inconsistencies and (depending on the option entered)

may prompt you for permission to repair them. The \fBmmfsck\fR

command tries to avoid actions that may result in loss of data. In some

cases, however, it may indicate the destruction of a damaged file.

.PP

If there are no file system inconsistencies to detect, the \fBmmfsck\fR

command reports this information for the file system:

.RS +3

.HP 3

\(bu Number of files

.HP 3

\(bu Used blocks

.HP 3

\(bu Free blocks

.RE

.PP

All corrective actions, with the exception of recovering lost disk blocks

(blocks that are marked as allocated but do not belong to any file), require

that the file system be unmounted on all nodes. If the \fBmmfsck\fR

command is run on a mounted file system, lost blocks are recovered but any

other inconsistencies are only reported, not repaired.

.PP

If a bad disk is detected, the \fBmmfsck\fR command stops the disk and

writes an entry to the error log. The operator must manually start and

resume the disk when the problem is fixed.

.PP

The file system must be unmounted on all nodes before the \fBmmfsck\fR

command can repair file system inconsistencies.

.SH "Parameters"

.PP

.RS +3

\fB\fIDevice\fR

\fR

.RE

.RS +9

The device name of the file system to be checked and repaired. 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-N {\fINode\fR[,\fINode\fR...] |

\fINodeFile\fR | \fINodeClass\fR}

\fR

.RE

.RS +9

Specify the nodes to participate in the check and repair of the file

system. This command supports all defined node classes. The

default is \fBall\fR (all nodes in the GPFS cluster will participate in the

check and repair 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-c

\fR

.RE

.RS +9

When the file system log has been lost and the file system is

replicated, this option specifies that the \fBmmfsck\fR command attempt

corrective action by comparing the replicas of metadata and data. If

this error condition occurs, it is indicated by an error log entry. The

\fB-c\fR and \fB-o\fR flags are mutually exclusive.

.RE

.PP

.RS +3

\fB-n

\fR

.RE

.RS +9

Specifies a \fBno\fR response to all prompts from the \fBmmfsck\fR

command. The option reports inconsistencies but it does not change the

file system. To save this information, redirect it to an output file

when you issue the \fBmmfsck\fR command.

.RE

.PP

.RS +3

\fB-o

\fR

.RE

.RS +9

Specifies that the file system can be mounted during the operation

of the \fBmmfsck\fR command. Online mode does not perform a full

file system consistency check, but blocks marked as allocated that do not

belong to a file are recovered. The \fB-c\fR and \fB-o\fR flags

are mutually exclusive.

.RE

.PP

.RS +3

\fB-y

\fR

.RE

.RS +9

Specifies a \fByes\fR response to all prompts from the \fBmmfsck\fR

command. Use this option only on severely damaged file systems.

It allows the \fBmmfsck\fR command to take any action necessary for

repairs.

.RE

.PP

.RS +3

\fB-t \fIDirectory\fR

\fR

.RE

.RS +9

Specifies the directory to be used for temporary storage during

\fBmmfsck\fR command processing. The default directory is

\fB/tmp\fR. The minimum space required (in byes) is equal to the

maximum number of inodes in the file system multiplied by 8.

.RE

.PP

.RS +3

\fB-v

\fR

.RE

.RS +9

Specifies the output is verbose.

.RE

.PP

.RS +3

\fB-V

\fR

.RE

.RS +9

Specifies the output is verbose and contain information for debugging

purposes.

.RE

.SH "Exit status"

.PP

.PP

.RS +3

\fB0

\fR

.RE

.RS +9

Successful completion.

.RE

.PP

.RS +3

\fB2

\fR

.RE

.RS +9

The command was interrupted before it completed checks or repairs.

.RE

.PP

.RS +3

\fB4

\fR

.RE

.RS +9

The command changed the file system and it must now be restarted.

.RE

.PP

.RS +3

\fB8

\fR

.RE

.RS +9

The file system contains damage that has not been repaired.

.RE

.SH "Security"

.PP

You must have root authority to run the \fBmmfsck\fR command.

.PP

You may issue the \fBmmfsck\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"

.RS +3

.HP 3

1. To run the \fBmmfsck\fR command on the \fBfs1\fR file system,

receive a report, but not fix inconsistencies, issue this command:

.sp

.nf

mmfsck fs1 -n

.fi

.sp

The system displays information similar to:

.sp

.nf

Checking "fs1"

Checking inodes

Checking inode map file

Checking directories and files

Checking log files

Checking extended attributes file

Checking allocation summary file

Checking policy file

Validated policy 'for stripe group fs1': parsed 3 Placement 

Rules, 0 Migrate/Delete/Exclude Rules

Checking filesets metadata

Checking file reference counts

Checking file system replication status

       1212416 inodes

         87560 allocated

             0 repairable

             0 repaired

             0 damaged

             0 deallocated

             0 orphaned

             0 attached

       7211746 subblocks

        227650 allocated

             0 unreferenced

             0 deletable

             0 deallocated

         44504 addresses

             0 suspended

File system is clean.

.fi

.sp

\fBmmfsck\fR found no inconsistencies in this file system.

.HP 3

2. To run the \fBmmfsck\fR command on the \fB/dev/fs2\fR file system,

receive a report, and fix inconsistencies, issue this command:

.sp

.nf

mmfsck /dev/fs2 -y\ 

.fi

.sp

The system displays information similar to:

.sp

.nf

Checking "/dev/fs2"

Checking inodes

Checking inode map file

Checking directories and files

Checking log files

Checking extended attributes file

Checking file reference counts

File inode 6912 is not referenced by any directory.

Reattach inode to lost+found? yes

Checking file system replication status

       33792 inodes

          46   allocated

           0   repairable

           0   repaired

           0   damaged

           0   deallocated

           1   orphaned

           1   attached

     3332520 subblocks

       19762   allocated

           0   unreferenced

           0   deletable

           0   deallocated

         728 addresses

           0   suspended

File system is clean.

.fi

.sp

.RE

.SH "See also"

.PP

mmcheckquota Command

.PP

mmcrfs Command

.PP

mmdelfs Command

.PP

mmdf Command

.PP

mmlsfs Command

.SH "Location"

.PP

\fB/usr/lpp/mmfs/bin\fR

.PP