Creating immutable filesets and files

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

  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: