You deduplicate data using the fsdedupadm command. The fsdedupadm command performs the following functions:
For more information about the keywords, see the fsdedupadm
(1M) manual page.
The following example creates a file system, creates duplicate data on the file system, and deduplicates the file system.
Example of deduplicating a file system
fsvol1
:# mkfs -t vxfs /dev/vx/rdsk/fsdg/fsvol1
/mnt1
:# mount -t vxfs /dev/vx/dsk/fsdg/fsvol1 /mnt1
temp1
, on /mnt1
and copy the file1
file into the directory:# mkdir /mnt1/temp1 # cd /mnt1/temp1 # cp /root/file1 . # /opt/VRTS/bin/fsadm -S shared /mnt1
Mountpoint Size(KB) Available(KB) Used(KB) Logical_Size(KB) Space_Saved(KB) /mnt1 20971520 19335962 346609 602609 0
The file1
file is approximately 250 MB, as shown by the output of the fsadm command.
temp2
, and copy the same file, file1
, into the new directory:# mkdir /mnt1/temp2 # cd /mnt1/temp2 # cp /root/file1 . # /opt/VRTS/bin/fsadm -S shared /mnt1
Mountpoint Size(KB) Available(KB) Used(KB) Logical_Size(KB) Space_Saved(KB) /mnt1 4194304 3588700 548740 548740 0%
By copying the same file into temp2
, you now have duplicate data. The output of the fsadm command show that you are now using twice the amount of space.
/mnt1
:# /opt/VRTS/bin/fsdedupadm enable -c 4096 /mnt1 # /opt/VRTS/bin/fsdedupadm list /mnt1
Chunksize Enabled SkipShared Schedule NodeList Filesystem --------------------------------------------------------------------- 4096 YES True NONE node1 /mnt1
/mnt1
:# /opt/VRTS/bin/fsdedupadm start /mnt1 UX:vxfs fsdedupadm: INFO: V-3-20: 0000: deduplication is started on /mnt1.
# /opt/VRTS/bin/fsdedupadm status /mnt1 Saving Status Node Type Filesystem -------------------------------------------------------------------------------- 42% COMPLETED fsaixp702-v05 MANUAL /mnt1 2014/09/23 22:48:22 Begin full scan. 2014/09/23 22:51:45 End detecting duplicates and filesystem changes.
# /opt/VRTS/bin/fsadm -S shared /mnt1
Mountpoint Size(KB) Available(KB) Used(KB) Logical_Size(KB) Space_Saved(KB) /mnt1 20971520 19335962 346609 602609 256000
The output shows that the used space is nearly identical to when you had only one copy of the file1
file on the file system.