LUN masking and "rule of 17"

Device masking with symmask - Yes, there are similarities to Clariion's Storage Groups, but essentially you are enabling access to one or more Symmetrix devices to one or more WWNs of initiator(s). There are also other things you can do such as enable heterogeneous port settings (similar to Clariion's host type setting usually automatically picked by the naviagent). If you are familiar with Clariions, think of mapping devices as picking which SP the LUN will be owned by (in symmetrix, which FA's will "own" the LUN). And think of masking as similar to adding the LUN(s) to a storage group, which will give visibility of the LUNs to the host. I would read EMC's masking manual as there are many things you can do such as LUN offsets (pre-72 microcode) and heterogeneous settings for different hosts.


As far as the rule of 17, it is indeed for FA redundancy from the host's perspective. Without going in to great detail, the backend of a Symmetrix is laid out in such a way that the rule of 17 provides the highest level or redundancy internal to the Symm. Also keep in mind that unlike a Clariion, a host can utilize both FA's at the same time as the Symm is an active/active array. Powerpath does a good job of this load balancing.

For resources about the SYMCLI, check out the Solutions Enabler manuals on Powerlink. There is a SYMCLI quick reference, and many other details documents available for download. Reading these manuals, along with using the commands will help you become savvy to the CLI toolset.