Oracle ASM ACFS File System Snapshot Management

 

How to Create Snapshots of an Oracle ACFS File System

$ /sbin/acfsutil snap create mysnapshot_20180926 /acfsmounts/acfs1

acfsutil snap create: Snapshot operation is complete.
$ ls -lrt /acfsmounts/acfs1/.ACFS/snaps/mysnapshot_20180926

How to Rename Snapshots of an Oracle ACFS File System

$ /sbin/acfsutil snap rename mysnapshot_20180926 mysnapshot_20180926_L0 /acfsmounts/acfs1

acfsutil snap rename: Snapshot operation is complete.

How to Find Oracle ACFS File System Snapshot Information

$ /sbin/acfsutil snap info -t mysnapshot_20180926_L0 /acfsmounts/acfs1
mysnapshot_20180926_L0    RO<= read only

How to Convert Oracle ACFS Snapshot from RO to RW

$  /sbin/acfsutil snap convert -w mysnapshot_20180926_L0 /acfsmounts/acfs1
acfsutil snap convert: Snapshot operation is complete.

$ /sbin/acfsutil snap info -t mysnapshot_20180926_L0 /acfsmounts/acfs1
mysnapshot_20180926_L0    RW

How to Restore ACFS File System from Snapshot 

The current master and all other snapshots will be deleted.

WARNING: This operation cannot be reversed.  Admin privileges
$ ls -lrt
total 80
drwx------ 2 oragrid oinstall 65536 Sep 26 13:37 lost+found
-rw-r--r-- 1 oragrid oinstall     0 Sep 26 14:19 a
-rw-r--r-- 1 oragrid oinstall     0 Sep 26 14:19 test
drwxr-xr-x 2 oragrid oinstall  8192 Sep 26 14:19 test_backup

Run the query as root user
File system must be unmounted

# umount /acfsmounts/acfs1
# /sbin/acfsutil snap remaster mysnapshot_20180926_L0 /dev/asm/vol3-69
fsck from util-linux 2.23.2
version                   = 12.2.0.1.0
Oracle ASM Cluster File System (ACFS) On-Disk Structure Version: 43.0
ACFS file system created at: Wed Sep 26 13:31:01 2018
Remastering snapshot 'mysnapshot_20180926_L0' as the master file system,
    deleting the current master file system,
    and deleting all the other snapshots.
    If you continue, 'snap remaster' must run to completion.
fsck.acfs: Do you want to continue? [0=no,1=yes]:
1
       'snap remaster' phase: 0
       'snap remaster' phase: 1
       'snap remaster' phase: 2
       'snap remaster' phase: 3
       'snap remaster' phase: 4
       'snap remaster' phase: 5
       'snap remaster' phase: 6
       'snap remaster' phase: 7
       'snap remaster' phase: 8
       'snap remaster' phase: 9

invoking ACFS Checker, which will check the remastered snapshot file system, and ACFS Fixer, which will reclaim released storage
*****************************
********** Pass: 1 **********
*****************************
checking primary file system
       Files checked in primary file system: 100%

reclaiming snap remaster released storage

*****************************
********** Pass: 2 **********
*****************************
checking primary file system
       Files checked in primary file system: 100%



*****************************
********** Pass: 3 **********
*****************************
checking primary file system
       Files checked in primary file system: 100%


        Checking if any files are orphaned...

        0 orphans found

Snapshot 'mysnapshot_20180926_L0' has been remastered as the master file system.

Yes I can see the snapshot has been restored to L0 and as expected all the snapshots has been deleted

#mount -t acfs /dev/asm/vol3-69 /acfsmounts/acfs1
cd /acfsmounts/acfs1
# ls -lrt
total 64
drwx------ 2 oragrid oinstall 4096 Sep 26 13:37 lost+found

# /sbin/acfsutil snap info  /acfsmounts/acfs1
    number of snapshots:  0
    snapshot space usage: 0  ( 0.00 )