This section provides instructions for setting the parameters for
Emulex or QLogic adapters on a SUN host system.
- Type cd /etc to change to the /etc subdirectory.
- Backup the system file in the subdirectory.
- Edit the system file and set the following parameters for servers
with configurations that only use Emulex or QLogic adapters.
- sd_max_throttle
- This sd_max_throttle parameter specifies the maximum number of commands
that the sd driver can queue to the host 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 connected LUN. Determine the value by using the
following formula: 256 ÷ (LUNs per adapter) where LUNs
per adapter is the largest number of LUNs that are assigned to a
single adapter.
To set the sd_max_throttle parameter for the storage unit
LUNs in this example, add the following line to the /etc/system file: set
sd:sd_max_throttle=5
- sd_io_time
- This parameter specifies the timeout value for disk operations. Add the
following line to the /etc/system file to set the sd_io_time parameter for
the storage unit 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 storage unit 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 12 6976 (124 KB). If
the I/O block size that you requested exceeds the default value, the request
is broken into more than one request. You should tune the value to the application
requirements. For maximum bandwidth, set the maxphys parameter by adding the
following line to the /etc/system file: set maxphys=1048576 (1 MB)
Note: Do
not set the value for maxphys greater than 1048576 (1 MB). Doing so can cause
the system to hang.