User guide

DataDirect Networks SFA™ OS 2.1.1.2 Release Notes Revision A2 | 11
• With RHEL6.2 and OFED 1.5.4.0 in an IB switch attached environment, it is possible
that a virtual disk on a controller may not be added back to the multipath device map
after a failover.
To find the offline device, issue the command:
lsscsi | awk -F/ '{print $NF}' | while read a; do printf "%s " $a; cat
,/sys/block/$a/device/state; done
To bring the device back online, issue the command:
#echo running > /sys/block/<sd??>/device/state and #multipath -r
where you replace <sd??> with the appropriate sd, for example sdaf, found from the
previous command.
A workaround for this issue is to update these packages:
o device-mapper:1.02.74-10.e16
o device-mapper-multipath: 0.4.9-56.el6_3.1.x86_64
DDN recommends that you install these as soon as possible.
• In an InfiniBand switch environment, there is a small chance that if a cable between
the switch and the controller is pulled, both the physical link and the logical link will
be lost. This has occurred with a Mellanox 6025F Switch and a Mellanox HCA.
• In an InfiniBand switch environment running RHEL 5.7, if a cable is pulled from
either an initiator or a target, a failover occurs as expected; however, once the
connection is reestablished, it does not fail back to the original controller.
o In order to resolve this issue, you must issue the command,
# udevtrigger.
o The Linux man pages state that the command will simply “request kernel
devices events for coldplug”. This will force udev to send a notification for
newly discovered path, which will allow the multipath daemon to detect that
the path has returned. After the multipath discovery takes place, I/Os can be
rebalanced back to allow the preferred paths to be used.
• In an InfiniBand switch environment, an online upgrade causes an I/O error while
upgrading the second controller with SLES 10 SP4. In an FC environment, there are
no issues because the discovery rate is much quicker. The only option for SFA
upgrades with SLES 10 SP4 is to perform the upgrade offline.
To perform the upgrade offline,
1. Issue the CLI command
set subsystem offline.
2. Perform the controller firmware upgrade on both controllers.
3. Issue the CLI command shutdown subsystem restart.
4. After both controllers come back online, issue the CLI command
application show discovered
_initiator. This should report “No
discovered_initiators exist.” This will be the state until a read request for
information from those SCSI devices is issued. Once the devices are
accessed, there will be a small delay as they are rediscovered by the system.
5.5 SFA12K-20, SFA12K-40, SFA10K-X, and SFA7700
In the GUI, the discovered initiators shown (from GUI Application > Show Initiators | Show
Subsystem Summary) includes erroneous status information for nonexistent ports 4, 5, 6, and
7. For the SFA7700 with the dual Fibre Channel card, the status display for ports 2 through 7
is erroneous as these ports are nonexistent as well. (DE10785)