What is the "wafl scan status" command?
Applies to
- Data ONTAP 8
- ONTAP 9
Answer
- WAFL uses various background scanners to perform file system operations
- Commonly snapshot creation or deletion are the two most common scanners
- To run this:
::> node run -node node1::> priv set advanced::> wafl scan status
- Scan ID - This is the process ID associated with the scan. The ID will not change if the process never completes, or if it is stopped
Note: wafl scan status is a command that requires advanced privileges for both Data ONTAP 7-mode and newer Clustered Data ONTAP/ONTAP systems. It is recommended to use only with NetApp personnel
Type of scans:
- active bitmap rearrangement: a scanner which performs optimizations on WAFL data structures. Not needed as of ONTAP 9
- container block reclamation: a scan which cleans up recently freed WAFL blocks on a per volume basis. The work performed by this scanner aids in calculating the free space in a volume. This is commonly ran during a snapshot deletion
- Inode to parent: Mapping of inode numbers to relative path names, which may be used in fpolicy in Data ONTAP 7-Mode. More details can be found in the article How to enable or disable I2P on a volume
- deswizzling: On Data ONTAP 7-mode and ONTAP 9 DP style SnapMirror destination volumes, this scan maps aggregate (physical) block locations to the volume block location, as the transfer does not include the physical disk block location. Please consult our article on deswizzling for more information on this
- snap create summary update: A scan to update internal metadata when a volume snapshot is taken
- blocks used summary update: A scan to update internal metadata of snapshot space usage when a volume snapshot is taken
- WAFL layout measurement: Part of the reallocate process
- cooling: Part of Fabricpool's technology which marks blocks as cool to be tiered
- tiering: Part of Fabricpool's technology which tiers warm data to cold storage
- inactive data reporting: A scan used to build report of blocks that are cold is built to understand data access patterns per volume
Note: There are more types of scans, but these are the most common ones
Additional Information
Example: Here is an example of running wafl scan status on ONTAP 9. The syntax is the same for 7-mode except for the first line
::*> wafl scan status Volume vol1: Scan id Type of scan progress 131021 container block reclamation block 245 of 673 (fbn 666) Volume vol2: Scan id Type of scan progress 131015 container block reclamation block 410 of 1050 (fbn 305) Volume vol3: Scan id Type of scan progress 131013 container block reclamation block 2463 of 4038 (fbn 3586) Volume vol4: Scan id Type of scan progress 131017 container block reclamation block 32 of 97 (fbn 63) Volume vol5: Scan id Type of scan progress 130504 WAFL layout measurement public inode 1599012 of 9074660, block 765 of 1996 Volume vol6: Scan id Type of scan progress 131029 container block reclamation block 5 of 20 (fbn 17) Volume vol7: Scan id Type of scan progress 131024 volume deswizzling snap 911, inode 4068843 of 6198122. level 1 of normal files. Totals: Normal files: L1:5/179926 L2:4/33564 L3:1/1237 L4:0/0 Inode file: L0:0/0 L1:0/0 L2:0/0 L3:0/0 L4:0/0 131023 container block reclamation block 1229 of 2019 (fbn 268) Volume vol8: Scan id Type of scan progress 131038 container block reclamation block 3 of 17 (fbn 6) Volume vol9: Scan id Type of scan progress 131020 volume deswizzling snap 910, inode 1822107 of 13286210. level 1 of normal files. Totals: Normal files: L1:14/95800 L2:8/169379 L3:1/10743 L4:0/0 Inode file: L0:0/0 L1:0/0 L2:0/0 L3:0/0 L4:0/0 131019 container block reclamation block 3684 of 8144 (fbn 6565)