>>>> Is a firmware upgrade disruptive to FC traffic? The docs seem to imply that it is not but don't explicitly state it.
In brocade firmware upgradation requires a reboot the switch to make it afect. So there would not be any I/O during this period. You should have a director switch, OR two separate fabric to upgrade switch firmware in 0 downtime.
>>>2. Given the two-revision limitation, would this be the correct path from 5.2.0a to 6.2.0g? 5.2.0a -> 6.0.1a -> 6.2.0g
Suppose the firmware version are as follows.. x.0 --> x.1 --> x.2 --> x.3 You can upgrade the firmware level directly from x.0 to x.2 But you cannot upgrade the firmware level directly from x.0 to x.3. You have to follow x.0 --> x.1 --> x.2 --> x.3 OR x.0 --> x.1 --> x.3 Means, you can skip only one version. If you are trying upgrade from x.0 to x.3, the section will end throwing error.
When you enter the firmwareDownload command, the switch says it will do a "warm/non-disruptive" reboot. That sounds to me like it does not disrupt FC traffic. After the download is complete, it then does a "HA reboot". I know it disrupts IP traffic (the telnet session) but does that step disrupt FC traffic?
"HA reboot" (High Available) is available in brocade director switches. What is the switch model? While rebooting if you are getting the option "HA reboot", then it should be director. Means switch internaly has two partion (Two processor, memory etc), while rebooting only one partition will go down. The other Processor will controll I/O. Means there is no down time.
So it sounds like if you enter "firmwareShow" and you get something indicating that there are two partitions then you can do a firmware update without FC traffic disruption.
The switches do have two (2) firmware 'partitions', but the idea is to be able to store two different versions and rollback quick. There is still only one processor for high-level functions. The low-level FC routing circuitry is not switched off while the embedded OS is reloaded.
A director (= larger switch) has two processors and the primary can quickly fail over the high-level functions to the standby processor before it is rebooting.
A note regarding upgrading: starting with firmware 5.3.x, the code enforces a single-version upgrade path, meaning you can no longer "skip" a revision. Your path would have to be:
5.2.0a -> 5.3.x -> 6.0.x -> 6.1.x -> 6.2.0g
If you try (for example) to upgrade directly from 5.3.x to 6.1.x, the upgrade process will error out.
On the non-director switches running a v4.1 code or later, non-disruptive upgrades are possible. I have a number of 2/32s (Brocade 3900) and 4/32 (Brocade 4100) that I have done this on.
On these switches, the HA Reboot saves the switching state to the flash filesystem and re-reads it after the reboot. The ASICs (low level components) will keep passing data during the reboot.
Starting with the upgrade to the v6.0 FOS releases, you can only upgrade from one release back.
