Why is the /proc/scsi/qla2xxx/ or /proc/scsi/lpfc/ directory missing in Red Hat Enterprise Linux 5 and what has replaced it?

Issue

• The 2.6.11 Linux kernel introduced certain changes to the lpfc (emulex driver) and qla2xxx (Qlogic driver) Fibre Channel Host Bus Adapter (HBA) drivers which removed the following entries from the proc pseudo-filesystem: /proc/scsi/qla2xxx, /proc/scsi/lpfc. These entries had provided a centralized repository of information about the drivers and connected hardware. After the changes, the drivers started storing all this information within the /sys filesystem. Since Red Hat Enterprise Linux 5 uses version 2.6.18 of the Linux kernel it is affected by this change.

• Using the /sys filesystem has the advantage that all the Fibre Channel drivers now use a unified and consistent manner to report data. However it also means that the data previously available in a single file is now scattered across a myriad of files in different parts of the /sys filesystem.

• One basic example is the status of a Fibre Channel HBA: checking this can now be accomplished with the following command:

# cat /sys/class/scsi_host/host#/state

• ...where host# is the H-value in the HBTL SCSI addressing format, which references the appropriate Fibre Channel HBA. For emulex adapters (lpfc driver) for example, this command would yield:

# cat /sys/class/scsi_host/host1/state
Link Up - Ready:
Fabric

• For qlogic devices (qla2xxx driver) the output would instead be as follows:

# cat /sys/class/scsi_host/host1/state
Link Up - F_Port