A partition key (pkey) is a unique ID assigned to an InfiniBand partition. The pkey of the default partition is 0x7fff. When a pkey is created, it is a 15-bit number. After the membership type is set, the pkey value becomes a 16-bit number. The Most Significant Bit (MSB) of the 16-bit pkey value denotes the membership type. A limited member has a value of 0, and a full member has a value of 1.
A full member can communicate with both full and limited members of the partition. However, a limited member can only communicate with a full member.
When assigning a pkey value for a unique, nondefault partition, you should select a 15-bit value. For example, 0x1234 with values from 0x0001 to 0x7fff. A total of 32767 pkeys are available. Do not assign pkeys that differ only in the MSB of their 16-bit numbers (for example, 0x8005 and 0x0005).
The term hybrid rack denotes an Exalogic machine on which half the compute nodes are in a physical configuration and the other half constitutes a virtualized data center. For more information about hybrid racks, see the Exalogic Elastic Cloud Release Notes.
On a hybrid Exalogic rack, Exalogic Control ensures that a unique pkey is assigned to each partition in the virtual environment. However, in the physical half of the rack, pkeys continue to be assigned manually, typically by the network administrator. The following guidelines will help ensure that the pkeys assigned manually to the partitions created in the physical half of a hybrid rack are different from those that Exalogic Control assigns automatically to partitions created in the virtual half of the rack.
Make a list (say, L1) of all the pkeys assigned to partitions that were created before the rack was converted to a hybrid configuration.
This set includes the pkey for the IPoIB-default partition (0x7fff) and pkeys for any nondefault partitions that were created in the physical configuration. Note that these pkeys are not guaranteed to be sequential, because they are assigned manually by administrators, who may be using different conventions for assigning pkeys to partitions. For example, for EoIB partitions, some administrators may follow the convention of assigning pkey values that match the VLAN IDs used for the EoIB networks.
Identify a list (say, L2) of pkeys to be assigned to partitions created in the physical half of the hybrid rack.
Select a list that is preferably near the upper end of the 0x0001–0x7ffe range. For example, if you identify 0x7000 to 0x7ffe as you range, you can create up to 4096 partitions. We recommend the upper end, because Exalogic Control assigns pkeys starting from lower end—that is, 0x0001.
In this list (L2), mark or remove the pkeys that were assigned before the rack was converted to a hybrid configuration—that is, the L1 list you created earlier.
As you create partitions, select pkeys from only the predetermined list (L2) and keep track of the pkeys that you are assigning.
Such an approach provides a reasonable guarantee that pkeys assigned in the physical environment are different from the pkeys that Exalogic Control assigns in the virtual half of the rack.
After the Exalogic machine is converted to a hybrid rack, for every network (either IPoIB or EoIB) that you create in the virtual half of the hybrid rack, Exalogic Control automatically assigns a unique pkey, starting from 0x0001. While selecting an unused pkey for a new partition, Exalogic Control will skip any pkeys (both L1 and L2) that are used for partitions in the physical half of the configuration. This way, every partition on the hybrid rack—regardless of whether it is on the physical or virtual part—will have a unique pkey.