Guidelines and Limitations

To design CFS regions for FC-Redirect, follow these guidelines:

• Ensure the CFS region configuration for FC-Redirect can be applied to all FC-Redirect-based applications. The applications include SME, Cisco DMM, and any future applications.

• Ensure that all FC-Redirect-capable switches that are connected to the hosts, targets, and the application switches (switches with MSM-18/4 modules in a cluster) are configured in the same region.

• If there are multiple SME clusters in a region, a target can be part of the SME configuration in only one cluster. To change the target to a different cluster, the configuration in the first cluster must be deleted before creating the configuration in the second cluster.

• All switches in the region must have a common VSAN.

• For existing SME installations, refer to “Configuring CFS Regions For FC-Redirect” section on page C-5 for steps on migrating to CFS regions.

• Remove all instances of the previous configurations when a switch is moved to a region or moved out of a region.

To configure a CFS region, refer to the “Configuring CFS Regions For FC-Redirect”.

Table 1-2 lists the SME configurations and the corresponding limits.

***Table 1-6*** ***SME Tape Configuration Limits***
Configuration	Limit
Number of clusters per switch	1
Switches in a cluster	4
Number of fc-redirect capable switches in a fabric	10
Fabrics in a cluster	2
Modules in a switch	11
Cisco MSM-18/4 modules in a cluster	32
Initiator-Target-LUNs (ITLs)	1024
LUNs behind a target	32
Host and target ports in a cluster	128
Number of hosts per target	128
Tape backup groups per cluster	4
Volume groups in a tape backup group	32
Keys in a Tape volume group	8000
Number of disk groups	128
Number of SME disks (LUNs)	2000
Cisco Key Management Center (number of keys)	32,000
Targets per switch that can be FC-redirected	32
IT connections per SME interface (soft limit)	256 Note Beyond this limit, a syslog message will be displayed. It is recommended that you provision more SME interfaces in the cluster.¹
IT connections per SME interface (hard limit)	512 Note Beyond this limit, new IT connections will not be assigned to that particular SME interface and a critical syslog will be displayed.²

***Table 1-7*** ***SME Disk Configuration Limits***
Configuration	Per Cluster	Per Switch	Per Crypto Node
Number of clusters	NA	2	1
Number of physical fabrics	2	NA	NA
Number of switches	8	NA	NA
Number of modules (line cards—SSN 16 or MSM-18/4 modules)	NA	11	NA
Cisco SME interfaces (crypto nodes used for encryption)	32	32	NA
Initiator-Target-LUNs (ITLs)	2048	2048	512
LUNs behind a target	512	512	512
Number of initiator ports	128	NA	NA
Number of target ports	128	NA	NA
Maximum number of IT nexus	128	NA	NA
Number of paths per LUN (physical paths per SME disk)	8	8	8
Number of disk groups	128	128	128
Number of SME disks (LUNs)	2048	2048	512
Cisco Key Management Center (KMC) number of keys	32,000	32,000	32,000
Maximum number of concurrent data preparations (offline data preparations)	NA	NA	64
Total number of Disk key replication relationships	2048

NA—Not applicable

Applicable from NX-OS Release 4.2(1) and later
Applicable from NX-OS Release 4.2(1) and later