ESXi FC paths to device are fewer than zoned paths

Products

• VMware vSphere ESXi

Issue/Introduction

• ESXi hosts are zoned at FC fabric level with a specific number of paths per device, for example, 8 paths.
  
  
• ESXi detects and establishes a smaller number of paths, e.g. 4 paths.
  
  
• There no dead paths or path related errors.

Environment

VMware vSphere ESXi (all versions)

Cause

This arises if the missing paths are not correctly zoned, or access is not provided to LUNs correctly via zoned storage target ports. 

This can typically be corroborated from the FC driver logging in the  ESXi /var/run/log/boot log by tracking the ESXi login to the fabric, and discovery of targets and devices.

Example with fnic driver (driver logging will vary by vendor):

1) The HBAs will log in to fabric
cpu41:2098112)nfnic: <1>: INFO: fdls_process_flogi_rsp: 450: FLOGI response accepted: fcid:0x###### fabric_wwpn:0x###############
cpu0:2098119)nfnic: <2>: INFO: fdls_process_flogi_rsp: 450: FLOGI response accepted: fcid:0x###### fabric_wwpn:0x###############

[fcid = fcid assigned to HBA by switch, fabric_wwpn = switch wwpn] 

2) Each HBA will query its FC swtich port and be returned a list of targets to which it is zoned for access:
cpu41:2098112)nfnic: <1>: INFO: fdls_send_gpn_ft: 1272: Sending fabric GPNFT for fcid:0x#######
cpu41:2098112)nfnic: <1>: INFO: fdls_process_gpn_ft_rsp: 2560: FDLS process GPN_FT response: iport state: 3 fabric state(10) len: 328
cpu41:2098112)nfnic: <1>: INFO: fdls_process_gpn_ft_tgt_list: 2404: FDLS process GPN_FT tgt list: 0x####### ctrl:0x0
cpu41:2098112)nfnic: <1>: INFO: fdls_create_tport: 2234: FDLS create tport: fcid: 0x####### wwpn: 0x###############
cpu41:2098112)nfnic: <1>: INFO: fdls_process_gpn_ft_tgt_list: 2404: FDLS process GPN_FT tgt list: 0x#######0 ctrl:0x0
cpu41:2098112)nfnic: <1>: INFO: fdls_create_tport: 2234: FDLS create tport: fcid: 0x####### wwpn: 0x###############
....

3) In turn, each HBA will query each target and be returned a list of LUNs to access via each target:
cpu53:2098114)nfnic: <1>: INFO: fnic_handle_report_lun: 1420: Report luns response for target_fcid : 0x###### target_id:# num_luns 30
cpu53:2098114)nfnic: <1>: INFO: fnic_handle_report_lun: 1420: Report luns response for target_fcid : 0x###### target_id:# num_luns 11
cpu53:2098114)nfnic: <1>: INFO: fnic_handle_report_lun: 1420: Report luns response for target_fcid : 0x###### target_id:# num_luns 130
...

Each HBA discovery of a device via a specific target = a zoned path. Each HBA will typically discover the same device via a number of targets

If the the number of device discoveries summed over all HBAs and targets equals the number of paths ESXI detects to the targets (no. of devices x no. of paths per device), then, this indicates that ESXi has created paths for all zoned connections notified to it from the fabric. 

Resolution

Review the zoning configuration on the FC fabric.