Users Guide

Broadcom DRVLin-LPe-UG124-100
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Emulex Drivers for Linux User Guide

The maximum number of LUNs supported on each driver port is 256.
 The maximum number of targets supported for each driver port is 255.
 The maximum number of driver ports in one zone is 64. This limit is based on the system’s ability to recover from link
events within the time constraints of the default timers.
The NPIV use-cases that involve a virtual server environment include associating a vPort with a virtual machine, and placing
the virtual machine in its own zone, which results in one vPort per zone. In the case of load-balanced environments, this can
increase typically to two vPorts per virtual machine, to a practical limit of something far less than 50.
In the NPIV cases not related to virtual server environments, zoning is typically initiator-zoning, again resulting in one vPort,
or a low number of vPorts in the case of load-balancing, within a given zone. If too many vPorts exist within a single zone,
expected behavior includes devices being lost after link events.
The minimum lifetime of a vPort is 60 seconds. An unenforced limit of 60 seconds exists between the creation of a vPort and
the deletion of the same vPort. vPorts are designed to exist for a long time in the system, and the creation of vPorts is
asynchronous, which means that a vPort might not be finished with FC or SCSI discovery when the command to create a
vPort is finished.
3.3 FC Driver Performance Tuning
This section describes how to tune the FC driver for best performance.
3.3.1 Overview
The configurable parameters lpfc_fcp_io_sched, and lpfc_fcp_imax can enhance performance on RHEL 7.5 and
earlier kernels.
The configurable parameters lpfc_hdw_queue and lpfc_irq_chann can enhance performance on the following
operating systems:
 RHEL 8.0 and later
 RHEL 7.6 and later
 SLES 15 and later
 SLES 12 and later
These features are available through module parameters that are defined in the FC driver as well as sysfs entries defined
by the Linux kernel.
This section provides more information about how the tuning parameters and script can improve Emulex adapter
performance.
NOTE: The parameters in this section do not apply to LPe12000-series adapters.
3.3.1.1 lpfc_fcp_io_sched
The lpfc_fcp_io_sched module parameter can be configured at driver load time. It also can be set dynamically as an
sysfs entry. The driver uses the parameter to determine which algorithm to use when scheduling an FCP I/O to an I/O
channel.
When multiple I/O channels are in use, I/Os can be scheduled to an I/O channel in a round-robin fashion, or by determining
which CPU is running when the I/O is submitted.