Steps For Major Version Upgrades Ndu In Nas And San Environments - IBM N Series Hardware Manual

Removing all old core files
Clear /etc/crash/ of old core files before performing the NDU. Run savecore -l to determine
whether there are any cores in memory and, if so, flush them as required.
Upgrading disk and shelf firmware
Shelf firmware upgrades must be completed before performing Data ONTAP NDU.
Disk firmware upgrades are automatically performed in the background for all drives starting
with Data ONTAP 8.0.2.
For more information about upgrading shelf and disk firmware, see 20.2, "Shelf firmware
NDU" on page 270 and 20.3, "Disk firmware NDU" on page 272.
Verifying system load
Perform NDUs only when processor and disk activity are as low as possible. The upgrade
process requires one controller to assume the load normally handled by both controllers. By
minimizing the system load, you reduce the risk of host I/O requests being delayed or timed
out.
Before initiating a Data ONTAP NDU, monitor processor and disk utilization for 30 seconds
with the following command at the console of each storage system controller:
sysstat -c 10 -x 3
Avoid having the values in the CPU and Disk Util columns e above 50% for all 10
measurements reported. Make sure that no additional load is added to the storage system
until the upgrade completes.
Synchronizing date and time
Make sure that the date and time are synchronized between the two controllers. Although
synchronized time is not required, it is important in case an issue arises that requires
examining time- and date-based logs from both controllers.
Connecting to the storage controllers
Using serial cables, a console server, and the system's remote LAN module (RLM) or a
baseboard management controller (BMC), open a terminal session to the console port of the
two storage controllers.
Network connections to the controllers are lost during takeover and giveback operations.
Therefore telnet, SSH, and FilerView sessions do not work for the NDU process.

20.1.6 Steps for major version upgrades NDU in NAS and SAN environments

The procedural documentation for running an NDU is in the product documentation on the
IBM Support site. See the "Upgrade and Revert Guide" of the product documentation for the
destination release of the planned upgrade.
For example, when doing an NDU from Data ONTAP 7.3.3. to 8.1, see the Data ONTAP 8.1
7-Mode Upgrade and Revert/Downgrade Guide at:
http://www.ibm.com/support/docview.wss?uid=ssg1S7003776
269
Chapter 20. Designing for nondisruptive upgrades