Release Notes Device Mapper Multipath Enablement Kit for HP StorageWorks Disk Arrays v4.2.0 (AA-RWF9G-TE, March 2009)

Known issues
Following are the known issues in the HPDM Multipath 4.2.0 release:
• Path failure messages are seen in the log file when encountered with a Unit Attention condition.
This behavior can be observed during online LUN addition, deletion, LUN transition across the
controller. These paths can be recovered after the polling interval set.
• multipath commands may take longer time to execute on heavily loaded servers or under path
failure conditions.
• User friendly multipath device names may change on reboot if /var is mounted on a partition
other than the root file system. It is recommended to have /(root) and /var on the same partition
or change the multipath bindings file location using the 'bindings_file' parameter in the
/etc/multipath.conf file.
• Blacklisting the multipath device in the /etc/multipath.conf file and restarting the multipath
service may not remove the device on RHEL 4 distributions. Execute the following command to
remove the blacklisted device:
# multipath -f <device>
• Using fdisk command to create partitions may fail to create Multipath device for the partition
device. It is recommended to use parted command to create partitions for the device.
• multipathd daemon crashes on systems configured with device paths more than the system
open file limits (default system open file limit=1024). It is recommended to change the system open
file limits by using either the 'max_fds' parameter in /etc/multipath.conf file or by using
the ulimit -n command and restart the multipathd demon.
• Multipath -l command may not reflect the correct path status for Logical Units presented from
MSA2012sa array when paths fail or are restored under heavy load conditions. To refresh the
path status, execute the # multipath -v0 command.
• Multipath devices may not be created for Logical Units when the system disks or internal controllers
are cciss devices. It is recommended to blacklist these devices in the /etc/multipath.conf
file and restart the multipathd daemon.
• If an existing LUN is deleted or unpresented from RHEL host, a DM multipath device with the invalid
WWN may be created which cannot be used and will be removed after the system reboots.
• For LUNs greater than 2TB in RHEL4 and SLES9 operating systems, DM multipath devices may
not be created with appropriate size.
Support
Telephone numbers for worldwide technical support are listed on the HP support website:
http://www.hp.com/support/
Collect the following information before calling the worldwide technical support:
• Technical support registration number (if applicable)
• Product serial numbers
• Product model names and numbers
• Applicable error messages
• Operating system type and revision level
• Detailed, specific questions
For continuous quality improvement, calls may be recorded or monitored.
Device Mapper Multipath Enablement Kit for HP StorageWorks Disk Arrays v4.2.0 13