Specifications

Setting the Sun host system parameters
The following sections contain the procedures to set the Sun host system
parameters for optimum performance on the ESS with the following adapters:
v JNI
v Emulex
v QLogic
JNI adapters
The following sections contain the procedures to set the Sun host system
parameters for optimum performance on the ESS with the JNI adapter:
1. Type cd/etc to change to the /etc subdirectory.
2. Backup the system file in the subdirectory.
3. Edit the system file and set the following parameters for servers with
configurations that use JNI adapters:
sd_max_throttle
This sd_max_throttle parameter specifies the maximum number of
commands that the sd driver can queue to the host bus adapter driver. The
default value is 256, but you must set the parameter to a value less than or
equal to a maximum queue depth for each LUN connected. Determine the
value using the following formula:
256/(LUNs per adapter)
The parameter shows thirty two 2105 LUNs attached to controller 1,
(c1t#d#), and forty eight 2105 LUNs attached to controller 2, (c2t#d#). The
value for sd_max_throttle is calculated using the controller with the highest
number of LUNs attached.
The sd_max_throttle parameter for the ESS LUNs in this example would be
set by adding the following line to the /etc/system file:
set sd:sd_max_throttle=5
sd_io_time
This parameter specifies the time-out value for disk operations. Add the
following line to the /etc/system file to set the sd_io_time parameter for the
ESS LUNs:
set sd:sd_io_time=0x78
sd_retry_count
This parameter specifies the retry count for disk operations. Add the
following line to the /etc/system file to set the sd_retry_count parameter for
the ESS LUNs:
set sd:sd_retry_count=5
maxphys
This parameter specifies the maximum number of bytes you can transfer for
each SCSI transaction. The default value is 126976 (124 KB). If the I/O
block size that you requested exceeds the default value, the request is
broken into more than one request. The value should be tuned to the
intended use and application requirements. For maximum bandwidth, set
the maxphys parameter by adding the following line to the /etc/system file:
set maxphys=8388608
118 ESS Host Systems Attachment Guide