In this
below note, I have configured the ADVM & ACFS mount point already. So I am creating
snapshot for the existing ACFS mount points. If you don’t have ACFS mount
points then we have to create it first.
What is ACFS Snapshot
The snapshot copy is space-efficient and uses Copy-On-Write functionality. Oracle ACFS snapshots are immediately available for use after they are created. The snapshots are created in the
.ACFS/snaps/ directory of the file system. They are always
online while the file system is mounted. Oracle ACFS read-write snapshots
enable fast creation of a snapshot image that can be both read and written
without impacting the state of the Oracle ACFS file system
1)
We can use the snapshot before installing
& removing patches for the $ORACLE_HOME or any application which are in production environment. We will have original
copy of data in the snapshot which we can move it at any time.
2)
Testing of new versions of application
software on production file data reflected in the read-write snapshot image
without modifying the original
production file system
3)
Running test scenarios on a real data set
without modifying the original production file system
4)
Oracle ACFS snapshot can support the online
recovery of files inadvertently modified or deleted from a file system.
View detail information on each
file system
To Collect more information about ACFS, you
will get it through the below view
oracrs +ASM1 > /sbin/acfsutil
info fs –h
It has penalty of option available on this view
To collect the
statistics for the ACFS Mount point
oracrs +ASM1 > /sbin/acfsutil
info fs /oracle/dbdump -s
amount of change
since mount: 0.11 MB
average rate of change
since mount: 0 KB/s
CREATE ACFS SNAPSHOTS
TO create a
snapshot in read-write or read-only mode
oracrs +ASM1> /sbin/acfsutil
snap create SNAP_PREUPGRADE /oracle/dbadmin
acfsutil snap create: Snapshot operation is
complete.
VIEW ACFS SNAPSHOTS
To know about the snapshot for the
particular mount in the ACFS, below command will work from 11.2.0.3 onwards
$ /sbin/acfsutil
snap info /oracle/dbdump
To view current snapshot files. All the
snapshot will be located under the mount point of the ACFS file system
.ACFS/snaps folder
oracrs +ASM1 >
cd /oracle/dbadmin/
oracrs +ASM1 > pwd
/oracle/dbadmin/.ACFS/snaps
oracrs +ASM1 > ls
-lrt
total 4
drwxrwxr-x 22 oracle oinstall 4096 Jan 20
11:42 SNAP_PREUPGRADE
oracrs +ASM1 >
To view the specific mount point information
and it gives us total no of snapshot available for the current mount point
oracrs +ASM1 > /sbin/acfsutil
info fs /oracle/dbadmin
/oracle/dbadmin
ACFS Version: 11.2.0.2.0
flags: MountPoint,Available
mount time: Thu Jan 12 09:58:51
2012
volumes: 1
total size: 20669530112
total free: 20450643968
primary volume: /dev/asm/acfs_vol1-98
label:
flags:
Primary,Available,ADVM
on-disk version: 40.0
allocation unit: 4096
major, minor: 252, 50177
size: 20669530112
free: 20450643968
ADVM diskgroup ACFS
ADVM resize increment: 268435456
ADVM redundancy: unprotected
ADVM stripe columns: 4
ADVM stripe width: 131072
number of snapshots: 1
snapshot space usage: 3198976
To view the snapshot information through
sqlplus
SQL> SELECT
SUBSTR(fs_name,1,34) FILESYSTEM,SUBSTR(snap_name,1,28) SNAPSHOT, CREATE_TIME
TIME FROM V$ASM_ACFSSNAPSHOTS;
FILESYSTEM SNAPSHOT TIME
----------------------------------
---------------------------- -----------
/oracle/dbadmin SNAP_PREUPGRADE 20-JAN-2012
DELETE ACFS SNAPSHOTS
oracrs +ASM1 >
/sbin/acfsutil snap delete SNAP_PREUPGRADE
/oracle/dbadmin
acfsutil snap
delete: Snapshot operation is complete.
To identify the file system which are
allocated through the ACFS
SQL> col
FS_NAME format a15
SQL> select *
from V$ASM_FILESYSTEM;
FS_NAME AVAILABLE_T BLOCK_SIZE STATE CORRU NUM_VOL TOTAL_SIZE
--------------- ----------- ----------
------------- ----- ---------- ----------
TOTAL_FREE TOTAL_SNAP_SPACE_USAGE
---------- ----------------------
/oracle/dbadmin 12-JAN-2012 4 AVAILABLE FALSE 1
19712
19492.9375 0
To know about the mount point and volumes
allocated in the ACFS
SQL> col
FS_NAME format a15
SQL> col
VOL_DEVICE format a15
SQL> col VOL_LABEL format a15
SQL> select *
from v$asm_acfsvolumes;
FS_NAME VOL_DEVICE VOL_LABEL PRIMA
TOTAL_MB FREE_MB
--------------- ---------------
--------------- ----- ---------- ----/oracle/dbadmin /dev/asm/acfs_v TRUE 19712 19492.9375
ol1-98
TO understand more about the current volume
statistics for ACFS volumes
SQL> col
VOLUME_NAME format a15
SQL> select *
from V$ASM_VOLUME_STAT;
GROUP_NUMBER VOLUME_NAME COMPOUND_INDEX VOLUME_NUMBER READS
WRITES
------------ --------------- --------------
------------- ---------- ----------
READ_ERRS WRITE_ERRS READ_TIME WRITE_TIME BYTES_READ BYTES_WRITTEN
---------- ---------- ---------- ----------
---------- -------------
1 ACFS_VOL1
16777217 1 23342
5887
0 0 12.073
18.228 34204672 5329920
SQL> col
VOLUME_NAME format a15
SQL> col USAGE
format a15
SQL> col
MOUNTPATH format a15
SQL> select
VOLUME_NAME,SIZE_MB,STRIPE_COLUMNS,USAGE,MOUNTPATH from v$asm_volume;
VOLUME_NAME SIZE_MB STRIPE_COLUMNS USAGE MOUNTPATH
--------------- ---------- --------------
--------------- ---------------
ACFS_VOL1 19712 4 ACFS /oracle/dbadmin
In
side the ASMCMD tool, we can find about the volumes through the below commands
volcreate
voldelete
voldisable
volenable
volinfo
volresize
volset
volstat
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