A-SIS is the technology of de-duplication introduced by NetApp FAS.
It’s trying to reduce the space usage of existing data with block-level de-dupe.
License is required.
Data OnTAP 7.3.2 need additional NearStore license.
sis on {vol_path}
sis status
sis start -s {vol_path}
Before dedupe:
node1> df -Vh
Filesystem total used avail capacity Mounted on
/vol/vol0/ 291MB 150MB 141MB 52% /vol/vol0/
/vol/vol0/.snapshot 0TB 0TB 0TB —% /vol/vol0/.snapshot
/vol/vol1/ 400MB 29MB 370MB 7% /vol/vol1/
/vol/vol1/.snapshot 100MB 0MB 100MB 0% /vol/vol1/.snapshot
After dedupe:
node1> df -Vh
Filesystem total used avail capacity Mounted on
/vol/vol0/ 291MB 150MB 141MB 52% /vol/vol0/
/vol/vol0/.snapshot 0TB 0TB 0TB —% /vol/vol0/.snapshot
/vol/vol1/ 400MB 15MB 384MB 4% /vol/vol1/
/vol/vol1/.snapshot 100MB 0MB 100MB 0% /vol/vol1/.snapshot
LUN environment is not suit for de-duplication
- The duplicate blocks will be moving to the available blocks in the remaining space of volume. That’s why additional space will be used by de-duplication with all of default LUN environment settings.
- Why will de-duplication use additional space to save the duplicate blocks, but not use space of the existing LUN space? Because the LUN space if it has been reserved, the host OS will consider the space of the LUN belongs to itself, so it can do anything like deleting/copying/moving on it with normal IO commands. If the duplicate blocks are saved on the LUN space, then problem occurs.
- The only possibility of using de-dupe technology in LUN environment is to make Thin Provisioning.