Dynamically Adding a Disk to an Online File System

Objectives:

Add a disk to a storage pool online Re-balance existing data in the file system

Requirements:

Complete Exercise 1: Installing the cluster A File System (Use Exercise 2 to create a file system if you do not already have one). Device to add         /dev/sd___

Step 1: Add a disk to the existing file system

Verify that GPFS is running and the file system is mounted using the mmgetstate command and the df command a. The mmgetstate command will show the status of the nodes in the cluster. > mmgetstate -a b. The df command will display the mounted GPFS file system. df Create a disk descriptor file /gpfs-course/data/adddisk.txt for the new disk using the format #DiskName:serverlist::DiskUsage:FailureGroup:DesiredName:StoragePool /dev/sd_:::dataOnly::nsd5:pool1 Use the mmcrnsd command to create the NSD > mmcrnsd -F /gpfs-course/data/adddisk.txt Verify the disk has been created using the mmlsnsd command > mmlsnsd The disk you just added should show as a (free disk) Add the new NSD to the fs1 file system using the mmadddisk command > mmadddisk fs1 -F /gpfs-course/data/adddisk.txt Verify the NSD was added using the mmdf command > mmdf fs1 disk disk size failure holds holds free KB free KB name in KB group metadata data in full blocks in fragments --------------- ------------- -------- -------- ----- -------------------- ------------------- Disks in storage pool: system nsd1 20971520 1 yes yes 20873984 (100%) 284 ( 0%) nsd2 20971520 2 yes yes 20873984 (100%) 202 ( 0%) ------------- -------------------- ------------------- (pool total) 41943040 41747968 (100%) 486 ( 0%) Disks in storage pool: pool1 nsd3 20971520 1 no yes 20969408 (100%) 62 ( 0%) nsd4 20971520 2 no yes 20969408 (100%) 62 ( 0%) nsd5 20971520 -1 no yes 20969408 (100%) 62 ( 0%) ------------- -------------------- ------------------- (pool total) 62914560 62908224 (100%) 186 ( 0%) ============= ==================== =================== (data) 104857600 104656192 (100%) 672 ( 0%) (metadata) 41943040 41747968 (100%) 486 ( 0%) ============= ==================== =================== (total) 104857600 104656192 (100%) 672 ( 0%) Inode Information ----------------- Number of used inodes: 4045 Number of free inodes: 78131 Number of allocated inodes: 82176 Maximum number of inodes: 82176

Step 2: Re-balancing the data

In some cases you may wish to have GPFS re-balance existing data over the new disks that were added to the file system. Often it is not necessary to manually re-balance the data across the new disks. New data that is added to the file system is correctly striped. Re-striping a large file system requires a large number of insert and delete operations and may affect system performance. Plan to perform this task when system demand is low. To re-balance the existing data in the file system use the mmrestripefs command. > mmrestripefs fs1 -b Use the mmdf command to view the utilization of each disk.