Managing file systems
There are several file system management tasks outlined in this topic.
For information on how to create GPFS™ file systems, see A sample file system creation and the mmcrfs command. For information on how to create GPFS file systems, see the A sample file system creation section in the
Managing filesets, storage pools and policies is also a file system management task. For more information on managing storage pools, filesets and policies, see Information lifecycle management for IBM Spectrum Scale. Use the following information to manage file systems in IBM Spectrum Scale.
Managing file system through GPFS GUI
To work with this function
in the GUI, log on to the IBM Spectrum
Scale GUI
and select Files > File
Systems.
Note: Creation of file systems is
not supported in the 4.2 GUI.
- Mounting a file system
You must explicitly mount a GPFS file system if this is the first time the file system is being mounted after its creation, or you specified not to automatically mount (-A no) the file system when you created it. - Unmounting a file system
Some GPFS administration tasks require you to unmount the file system before they can be performed. You can unmount a GPFS file system using the mmumount command. - Deleting a file system
Before deleting a file system, unmount it on all nodes. - Determining which nodes have a file system mounted
The mmlsmount command is used to determine which nodes have a given file system mounted. The name and IP address of each node that has the file system mounted is displayed. This command can be used for all file systems, all remotely mounted file systems, or file systems mounted on nodes of certain clusters. - Checking and repairing a file system
The mmfsck command finds and repairs conditions that can cause problems in your file system. The mmfsck command operates in two modes: online and offline. - Dynamic validation of descriptors on disk
IBM Spectrum Scale can periodically scan descriptors on disk to detect and fix corruption early rather than waiting until the next remount. - Listing file system attributes
Use the mmlsfs command to display the current file system attributes. Depending on your configuration, additional information that is set by GPFS can be displayed to help in problem determination when you contact the IBM® Support Center. - Modifying file system attributes
Use the mmchfs command to modify existing file system attributes. - Querying and changing file replication attributes
If your availability requirements change, you can have GPFS display the current replication factors for one or more files by issuing the mmlsattr command. You might then decide to change replication for one or more files using the mmchattr command. - Using Direct I/O on a file in a GPFS file system
The Direct I/O caching policy can be set for files in a GPFS file system by specifying the -D option on the mmchattr command. - File compression
You can compress or decompress files either with the mmchattr command or with the mmapplypolicy command with a MIGRATE rule. You can do the compression or decompression synchronously or defer it until a later call to mmrestripefile or mmrestripefs. - Setting the Quality of Service for I/O operations (QoS)
QoS limits the effect of I/O-intensive GPFS maintenance commands on overall system I/O performance. - Restriping a GPFS file system
Writing data into a GPFS file system correctly stripes the file. However, if you have added disks to a GPFS file system that are seldom updated, use the mmrestripefs command to restripe the file system to achieve maximum performance. You can also use mmrestripefs to perform any incomplete or deferred file compression or decompression. - Querying file system space
Although you can use the df command to summarize the amount of free space on all GPFS disks, the mmdf command is useful for determining how well-balanced the file system is across your disks. (Also, the output from mmdf can be more up to date than the output from df.) Additionally, you can use the mmdf command to diagnose space problems that might result from fragmentation. - Querying and reducing file system fragmentation
Disk fragmentation within a file system is an unavoidable condition. When a file is closed after it has been written to, the last logical block of data is reduced to the actual number of subblocks required, thus creating a fragmented block. - Protecting data in a file system using backup
GPFS provides ways to back up the file system user data and the overall file system configuration information. - Scale Out Backup and Restore (SOBAR)
Scale Out Backup and Restore (SOBAR) is a specialized mechanism for data protection against disaster only for GPFS file systems that are managed by IBM Spectrum Protect™ Hierarchical Storage Management (HSM). For such systems, the opportunity exists to pre-migrate all file data into the HSM storage and take a snapshot of the file system structural metadata, and save a backup image of the file system structure. This metadata image backup, consisting of several image files, can be safely stored in the backup pool of the IBM Spectrum Protect server and later used to restore the file system in the event of a disaster. - Scheduling backups using IBM Spectrum Protect scheduler
The IBM Spectrum Protect scheduler typically utilizes the IBM Spectrum Protect Backup-Archive client backup commands that should be avoided in the IBM Spectrum Scale setup. Instead, you can configure a IBM Spectrum Protect client schedule to call a script as described in the following steps. - Configuration reference for using IBM Spectrum Protect with IBM Spectrum Scale
When using the IBM Spectrum Protect client in an IBM Spectrum Scale environment, several options in the dsm.sys and dsm.opt configuration files need to be taken into consideration. - Restoring a subset of files or directories from a local file system snapshot
You can restore a subset of files or directories from a local snapshot of a file system in case of accidental deletion. - Restoring a subset of files or directories from a local fileset snapshot
You can restore a subset of files or directories from a local snapshot of an independent fileset in case of accidental deletion. - Restoring a subset of files or directories from local snapshots using the sample script
You can restore a subset of files or directories from local snapshots using a sample script in case of accidental deletion.
Parent topic: Administering