Adding Disk Cache to a File System

To increase the disk cache for a file system, you add disk partitions or disk drives, and then update the mcf file and use the samgrowfs command to expand the file system. You do not need to reinitialize or restore the file system.

When making changes to the mcf file, be aware of the following:

• You can configure up to 252 disk partitions in a file system.

• To increase the size of a Sun QFS file system, you must add at least one new metadata partition. Metadata partitions require an Equipment Type value of mm.

• If you want to add new partitions for metadata or for data, add them to the mcf file after the existing disk partitions.

• Do not change the Equipment Identifier name in the mcf file. If the name in the mcf file does not match the name in the superblock, the file system can no longer be mounted. Instead, the following message is logged in /var/adm/messages:

  WARNING SAM-FS superblock equipment identifier <id> 
  on eq <eq> does not match <id> in mcf

How to Add Disk Cache to a File System

1. Unmount the file system you want to expand. If the file system is shared, unmount the file system on all client hosts and then on the metadata server.

   You can then perform the remaining steps in this procedure on the metadata server. For more information about unmounting a file system, see Unmounting File Systems in Sun QFS and Sun Storage Archive Manager 5.3 Installation Guide.

2. If you want to rename the file system during this procedure, use the samfsck command with the -R and -F options.

   For more information, see the samfsck(1M) man page.

3. In the /etc/opt/SUNWsamfs/mcf file, add the disk cache.
4. Check for errors in the mcf file.

   # sam-fsd

   If the output from this command shows errors, correct them before proceeding to the next step.

5. Propagate the mcf file changes to the system:

   # samd config

   For more information, see the samd(1M) man page.

6. Issue the samgrowfs command on the file system that is being expanded.

   For example, type the following command to expand file system samfs1:

7. Mount the file system.

   For information about mounting a Sun QFS file system, see the mount_samfs(1M) man page.

8. If the file system is a Sun QFS shared file system, edit the mcf file on each participating client host to match the metadata server's mcf file.