Hitachi Dynamic Link Manager Software Users Guide for Linux

Notes on Using HDLM
Note the following when using HDLM.
Notes Common to OSs
The following notes are common to OSs:
• Do not activate the same volume group concurrently from multiple
servers.
• When a path error exists, the period of time required to return a response
to the application that made an I/O request to HDLM depends on the
timeout values specified for the fibre channel switch and HBA.
Therefore, if an error occurs in all the paths for a single LU, this response
time will be the total period of time required for the corresponding fibre
channel switches and HBAs to detect a timeout for the I/O requested for
each path.
For details on the timeout values for fibre channel switches and HBAs, see
the appropriate manual for the device. The following figure gives an
overview of the period required to return a response from the time an
application requests an I/O to the time the application receives the
response.
4-2
HDLM Operation
Hitachi Dynamic Link Manager (for Linux®) User Guide