PRIMECLUSTER Global File Services Configuration and Administration Guide 4.1 (Linux)

9.2.2.4 Setting MDS operational information

The following is an example of creating a typical GFS Shared File System specifying MDS operation information to improve availability:

• Priority settings of MDS placement

  The -o node option of sfcmkfs(8) specifies the priority of placing the primary MDS and the secondary MDS. The primary MDS and secondary MDS candidates are set according to order of specifying shared host names.

  The following shows an example of creating a file system using sfcmkfs(8) in the situation where mikan is placed as the primary MDS Candidate, and Karin, as the secondary MDS candidate.

 
# sfcmkfs -o node=mikan,karin,mango,akebi /dev/sfdsk/gfs/dsk/volume1
 
Representative partition (meta-data, log and data) : /dev/sfdsk/gfs/dsk/volume1
Shared hosts   :  mikan, karin, mango, and akebi
Primary MDS    :  mikan
Secondary MDS  :  karin

• Configuration that enables MDS placement on all nodes

  To enable MDS placement on all nodes, use the -o mdsnode option of the sfcmkfs(8) command.

  The following shows an example of creating a file system using sfcmkfs(8) when MDS is placed on all nodes.

 
# sfcmkfs -o mdsnode=all,node=mikan,karin,mango,akebi /dev/sfdsk/gfs/dsk/volume1
 
Representative partition (meta-data, log and data) : /dev/sfdsk/gfs/dsk/volume1
Shared hosts   :  mikan, karin, mango, and akebi
Primary MDS    :  mikan
Secondary MDS  :  karin
Host on which MDS can be placed :  mikan, karin, mango, akebi

• Configuration that restricts the range of MDS placement

  To restrict the MDS placement range to specific shared hosts, use the -o mdsnode option of the sfcmkfs(8) command to specify the number of nodes.

  The following shows an example of creating a file system using sfcmkfs(8) with the placement range of MDS restricted to three nodes.

 
# sfcmkfs -o mdsnode=3,node=mikan,karin,mango,akebi /dev/sfdsk/gfs/dsk/volume1
 
Representative partition (meta-data, log and data) : /dev/sfdsk/gfs/dsk/volume1
Shared hosts   :  mikan, karin, mango, and akebi
Primary MDS    :  mikan
Secondary MDS  :  karin
Host on which MDS can be placed :  mikan, karin, and mango