Dell Brocade Adapters - Manual (Page 138)

114 Brocade Adapters Troubleshooting Guide
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Tuning storage drivers
4
Robert Love, 2nd edition, 2005
Solaris tuning
To increase I/O transfer performance, set the following parameters on your system:
• Set the maximum device read/write directive (maxphy).
• Set the disk maximum transfer parameter (ssd_max_xfer_size).
Please refer to the Sun StorageTek SAM File System Configuration and Administration Guide
document for details of the two parameters.
To increase I/O write performance, set the pcie-max-read-reqsz parameter on your system. This
parameter is defined in /kernel/drv/bfa.conf. It determines the maximum read through PCIe. The
default value is 512. To increase performance, you can increase the value to 256, 1024, or 2048.
NOTE
Brocade 804 and 1007 adapters are not supported on Solaris systems so Solaris commands do not
apply to these adapters.
Windows tuning
Windows tuning involves configuring the driver and operating system tunable parameters.
Driver tunable parameters
You can manipulate several driver parameters to increase performance.
bfa_lun_queue_depth (outstanding I/O requests per LUN)
The driver uses a default LUN queue depth value of 32. This value is chosen to reflect the average
operating I/O load in most scenarios. Storport manages the I/O throttling at the per-LUN level to
guarantee the configured queue depth. During performance testing with specific high-end array
LUNs, it may be necessary to increase this I/O queue depth to a much larger value. Microsoft
recommends a value of 96 during high-performance testing scenarios. If the queue depth is not
sufficient, then you will notice performance degradation.
The queue depth can be configured at the following registry location with any value within the
range 1 through 254.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\bfad\Parameters\Device\bfa_lun_
queue_depth
Interrupt moderation using interrupt coalescing feature
Moderating interrupts can often result in reduced CPU load on the host but, unless interrupt
moderation is performed intelligently, the CPU savings might increase latency.
The default values for the Fibre Channel port interrupt attributes are configured as follows:
• Interrupt coalescing
Default: ON