210 Implementing the IBM General Parallel File System (GPFS) in a Cross-Platform Environment
5. Add the remotefs to cluster 2, as shown in Example 4-34.
Example 4-34 The mmremotefs add command: Adding a remote file system to the current cluster
germany:/tmp/auth#mmremotefs add /dev/remotemantestfs2 -f /dev/mantestfs2 -C
testcluster2.england
-T /remotemantestfs2
mmremotefs: Propagating the cluster configuration data to all
affected nodes. This is an asynchronous process.
In this way, you can see which remotefs has been configured by using the mmremotefs
command, as shown Example 4-35.
Example 4-35 Using the mmremotefs command to see configured remote file systems
germany:/#mmremotefs show all
Local Name Remote Name Cluster name Mount Point Mount Options Automount Drive Priority
remotemantestfs2 mantestfs2 testcluster2.england /remotemantestfs2 rw no -
0
6. Mount the remotefs on cluster 2 by using the standard mmount command. See
Example 4-36.
Example 4-36 Using the mmount command to mount remote file system
germany:/tmp/auth#mmmount /remotemantestfs2
Thu Jul 1 11:48:00 EDT 2010: mmmount: Mounting file systems ...
/dev/remotemantestfs2 52428800 52108800 1% 4038 12%
/remotemantestfs2
4.2.5 Adding or removing a file system
To add a new file system to a cluster, use the mmcrfs command. The command has several
options. See Example 4-37.
Example 4-37 The mmcrfs command options
germany:/tmp/power#mmcrfs -?
Usage:
mmcrfs Device {"DiskDesc[;DiskDesc...]" | -F DescFile}
[-A {yes | no | automount}] [-B BlockSize] [-D {posix | nfs4}]
[-E {yes | no}] [-j {cluster | scatter}] [-k {posix | nfs4 | all}]
[-K {no | whenpossible | always}] [-L LogFileSize]
[-m DefaultMetadataReplicas] [-M MaxMetadataReplicas]
[-n NumNodes] [-Q {yes | no}] [-r DefaultDataReplicas]
[-R MaxDataReplicas] [-S {yes | no}] [-T Mountpoint]
[-t DriveLetter] [-v {yes | no}] [-z {yes | no}]
[--filesetdf | --nofilesetdf]
[--inode-limit MaxNumInodes[:NumInodesToPreallocate]]
[--mount-priority Priority] [--version VersionString]
Chapter 4. Management and maintenance 211
The following list shows the options required to create a new file system with the mmcrfs
command, as in Example 4-38:
Device A name that you want to give to this new device,
DiskDesc The disk descriptors list, or directly the disk descriptions file (-F)
-F DescFile The file that has been modified by the mmcrnsd command.
-T Sets the mount point, here an example of a newly created file system.
Example 4-38 The mmcrfs command: Creating a completely new file system
germany:/gpfs#cat nsd.conf
# hdisk1:::dataAndMetadata:80:nsdhdisk2:
nsdhdisk2:::dataAndMetadata:80::
# hdisk2:::dataAndMetadata:80:nsdhdisk3:
nsdhdisk3:::dataAndMetadata:80::
# hdisk3:::dataAndMetadata:80:nsdhdisk4:
nsdhdisk4:::dataAndMetadata:80::
# hdisk4:::dataAndMetadata:80:nsdhdisk5:
nsdhdisk5:::dataAndMetadata:80::
germany:/gpfs#mmcrfs testnewfs -F nsd.conf -T /testnewfs
The following disks of testnewfs will be formatted on node usa:
nsdhdisk2: size 26214400 KB
nsdhdisk3: size 26214400 KB
nsdhdisk4: size 26214400 KB
nsdhdisk5: size 26214400 KB
Formatting file system ...
Disks up to size 1.1 TB can be added to storage pool 'system'.
Creating Inode File
Creating Allocation Maps
Clearing Inode Allocation Map
Clearing Block Allocation Map
Formatting Allocation Map for storage pool 'system'
Completed creation of file system /dev/testnewfs.
mmcrfs: Propagating the cluster configuration data to all
affected nodes. This is an asynchronous process.
Notice the output line:
Disks up to size 1.1 TB can be added to storage pool 'system'.
This value is calculated during file system creation time when the mmcrfs command is issued,
because on each disk there is a portion where GPFS stores its control information and a disk
bitmap that shows, in the disk, which area is allocated or not. Therefore, if you try to add a
bigger disk to the same storage pool, and the space is not enough, GPFS provides, in
advance, the maximum disk size you can add to this storage pool.
Now, we re-create the same file system with the same parameters, but exclude the nsdhdisk2
disk, resulting in smaller disks, as shown Example 4-39 on page 212.

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