atime synchronization example

The following example shows how to use the atime attribute to trigger retention for the existing wind.jpg object after atime synchronization has been enabled for the namespace; the example uses the NFS protocol:

Procedure

  1. (Optional) Check the current retention setting for the wind.jpg object:

    cat /metadatamount/images/wind.jpg/retention.txt
    0
    Deletion Allowed
  2. (Optional) Check the current permissions for the wind.jpg object:

    ls -l /datamount/images/wind.jpg
    -r--r--r-- 1 root root 23221 Mar 19 09:45 /datamount/images/wind.jpg

    Notice that the object has no write permissions.

  3. Set the atime attribute for the wind.jpg object:

    touch -a -t 201512310000 /datamount/images/wind.jpg
    NoteTo set the value of the atime attribute, you can use the Windows SetFileTime library call, the Unix utime library call, or the Unix touch command.
  4. (Optional) Verify step 3:

    stat /datamount/images/wind.jpg
    File: "/datamount/images/wind.jpg"
    Size: 23221 Blocks: 112 IO Block: 32768 regular file
    Device: 15h/21d Inode: 18 Links: 1
    Access: (0444/-r--r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
    Access: 2015-12-31 00:00:00.000000000 -0500
    Modify: 2012-03-19 09:45:18.000000000 -0400
    Change: 2012-03-23 13:10:17.000000000 -0400
  5. Add write permissions to the wind.jpg object:

    chmod a+w /datamount/images/wind.jpg
  6. Remove all write permissions from the wind.jpg object:

    chmod a-w /datamount/images/wind.jpg
  7. (Optional) Verify that the retention setting has changed to match the atime value:

    cat /metadatamount/images/wind.jpg/retention.txt
    1451520000
    2015-12-31T00:00:00-0500