Creating immutable filesets and files

To configure and deploy a WORM solution, it is mandatory to create an immutable fileset in IBM Storage Scale.

About this task

Procedure

  1. Create an independent fileset by using the mmcrfileset command.
  2. Link the fileset to a directory within the file system which must not exist at this point: 
    mmlinkfileset <file system name> <fileset name> -J directory
    Note: This directory is the immutable fileset path.
  3. Set an IAM mode for the files by using the following command: 
    mmchfileset <file system name> <fileset name> --iam-mode compliant
  4. Create a test file date > testfile with read-write permissions and fill the file with some content: 
    echo “Hello World” > file
  5. Check the extended attributes of the file which indicate that the file is not immutable by using the mmlsattr command: 
    mmlsattr -L testfile
file name: testfile
metadata replication: 1 max 2
data replication: 1 max 2
immutable: no
appendOnly: no
indefiniteRetention: no
expiration Time: Wed Mar 15 17:16:13 2016
flags:
storage pool name: system
fileset name: WORMfs
snapshot name:
creation time: Wed Mar 15 17:16:13 2016
Misc attributes: ARCHIVE
Encrypted: no
  6. Set the file to read-only: 
    chmod –w testfile
  7. Set the future expiration time using mmchattr. Select a time in the immediate future for quick expiry and deletion. 
    mmchattr --expiration-time 2016-03-15@18:16:13 testfile
  8. Verify that immutability and expiration time are set by using mmchattr: 
    
mmlsattr -L testfile
file name: testfile
metadata replication: 1 max 2
data replication: 1 max 2
immutable: yes
appendOnly: no
indefiniteRetention: no
expiration Time: Wed Mar 15 18:16:13 2016
flags:
storage pool name: system
fileset name: WORMfs
snapshot name:
creation time: Wed Mar 15 17:16:13 2016
Misc attributes: ARCHIVE READONLY
Encrypted: no
  9. Verify that the files cannot be modified or deleted. Run the following commands: 
    chmod +w testfile
    The system displays an output similar to this:
    chmod: changing permissions of 'testfile': Operation not permitted
    date > testfile
    The system displays an output similar to this:
    testfile: Read-only file system
    rm -f testfile
    The system displays an output similar to this:
    
 rm: cannot remove 'testfile': Read-only file system
    For more information, see the following topics: