What are the best practices of shelf numbering for attaching SAS shelves to a storage system?
Applies to
- ONTAP OS
- Disk Shelves
- SAS Shelves
Answer
What are the best practices of shelf numbering for attaching SAS shelves to a storage system?
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Each SAS shelf directly attached to a High-Availability (HA) controller pair, or to a standalone non-HA controller, requires a unique Shelf ID in the range 0-98. In instances where the node contains internal disks, the internal shelf is set to ID 0, leaving ID's 1-99 available for external shelves.
In a clustered Data ONTAP environment, the shelf IDs only need to be unique within an HA pair, not across the entire cluster.
For example, if HA pair Node01/Node02 used Shelf ID 10, then HA pair Node03/Node04 may also use Shelf ID 10 if so desired.
Note that when Shelf IDs are repeated across a cluster, extra care should be taken to ensure that any maintenance required is performed on the correct shelf - such as verifying the shelf serial number - and not relying soley on the Shelf ID for identification.
Note: NetApp recommends numbering shelves in stacks by the 10's rule.
For a filer with no internal disks the number would be as follows:
Node 1:
- Stack 1 contains shelf ID's 0-9
- Stack 2 contains shelf ID's 10-19
Node 2:
- Stack 1 contains shelf ID's 20-29
- Stack 2 contains shelf ID's 30-39
In the case of a filer with internal disks and dual PCM's (i.e. FAS2240 series), the above would change to:
Node 1:
- Stack 1 contains shelf ID's 1-9
- Stack 2 contains shelf ID's 10-19
Node 2:
- Stack 1 contains shelf ID's 20-29
- Stack 2 contains shelf ID's 30-39
Additional Information
Further information regarding specific shelves may be found in the documentation library.