Service manual

Troubleshooting 3-55
• A read operation reads from a specified device into a buffer.
• A write operation writes from a buffer to a specified device.
• A compare operation compares the contents of the two buffers.
• The exer command uses two buffers, buffer 1 and buffer 2, to carry out the
operations. A read or write operation can be performed using either buffer.
A compare operation uses both buffers.
You can tailor exer by using options to specify the following:
• An address range to test within the test device(s)
• The packet size (number of bytes read or written in one I/O operation)
• The number of passes to run
• How many seconds to run for
• A sequence of individual operations performed on the test device(s). The
qualifier used to specify this is called the action string qualifier.
If you simply specify “exer <device>”, the exerciser will do one pass of random
reads of the entire device (which could take many minutes).
CAUTION: Running exer on disks can destroy data on the disks.
Syntax
exer [-sb start_block] [-eb end_block] [-p pass_count]
[-l blocks] [-bs block_size] [-bc blocks_per_io]
[-d1 buf1_string] [-d2 buf2_string]
[-a action_string] [-sec seconds] [-m] [-v] [-delay millisecs] device_name