Setting Parameters For Emulex Adapters - IBM TotalStorage DS6000 Attachment Manual

Setting parameters for Emulex adapters

This section provides instructions for setting parameters for Emulex adapters for
your PRIMEPOWER host system.
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
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DS6000 Host Systems Attachment Guide
configurations that only use Emulex or QLogic adapters.
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 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 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.