As you probably already know ONTAP manages disks in groups called aggregates. An aggregate is build from one or more RAID group. Any given disk can be only a member of a single aggregate. Of course, if you read my previous entry you already know this is not always the truth. The exception is when you have partitioned disks (if you haven’t check that out yet, i wrote an short article on that subject here: NetApp cDOT – Advanced Drive Partitioning).
If terms like an aggregate or RAID group are quite new to You, please refer to my older entries: NetApp – Data ONTAP storage architecture – part 1 and NetApp – Data ONTAP storage architecture – part 2.
In this entry I would like to show you how to build new aggregate, how to extend one, and how to manage your spare disks, and how to utilize your brand new disks.
Manage new disks
Once the new shelf is connected to Your cluster new disks should be assigned to one node as spare disks. It depends on Your auto assign option, and auto-assign policy if the disks will be automatically assigned, or not. You can verify that with disk option show command:
cDOT_cluster::> disk option show Node BKg. FW. Upd. Auto Copy Auto Assign Auto Assign Policy ------------- ------------- ------------ ------------- ------------------ cDOT_node1 on on on shelf cDOT_node2 on on on shelf 2 entries were displayed.
Based on my output you can notice that the assign asign is on, and the policy is shelf. Possible policies are:
- stack – automatic ownership at the stack or loop level
- shelf – automatic ownership at the shelf level
- bay – automatic ownership at the bay level
- default – policy depends on the system model
If there are multiple stacks or shelves, that have different ownership, one disk must be manually assigned on each shelf/stack before automatic ownership assignment will work.