Reader Feedback: More on Preventing System Startup, Attention Lights, and Adding Drives
July 9, 2008 Joe Hertvik
In recent articles, I discussed some techniques for preventing your subsystems from restarting after a full system backup; turning off your iSeries, System i, and Power i attention lights; and preparing to add disk drives to your system. After publishing these tips, several readers wrote in with corrections, additions, and stories that flesh out the techniques even further. This week, let’s look at what you had to say and see what additional information we can pick up from them.
More On Stopping Your System i From Starting Up
After printing a tip on stopping your controlling subsystem from restarting after performing an Option 21 (full system backup) from the GO SAVE menu, several readers wrote me about another technique for keeping their systems in restricted mode. Their technique centered around using the system’s IPL attributes to keep it in a restricted state.
Here’s what reader Tom Kreimer had to say:
I prefer to set the Start to Restricted State (STRRSTD) parameter to *YES on the “Change IPL Attributes” command (CHGIPLA) instead of changing my startup program system value to *NONE. Its advantage is that it is a one line change, and it changes itself back to *NO automatically for the next IPL. I recommend that you don’t mess with the other CHGIPLA attributes for this purpose, as STRRSTD is enough to get it done. Also, be sure to read the help text for each CHGIPL parameter you change. Some changes are permanent, and some are temporary (i.e., they flip back to their original state after the IPL).
Dennis from South Africa and Trevor Briggs also wrote in with similar comments. For more information on using STRRSTD to put your system in restricted mode after an IPL, check out this article on IPLing into Restricted State.
The problem with using STRRSTD in this situation was that the tip called for a solution for keeping the system in restricted after an Option 21 backup. When you set STRRSTD to *YES, its only purpose is to prevent your controlling subsystem from starting after an IPL and leaving your system in restricted state. For a full system backup using Option 21, the backup routine itself puts the system into restricted state before the backup and then restarts the controlling subsystem afterward. Restarting the controlling subsystem activates your startup program, which takes the system out of restricted state. STRRSTD doesn’t have any effect in this situation because it (as far as I know) doesn’t affect how Option 21 restarts the controlling subsystem. That was why I didn’t recommend using it to solve the reader’s problem. The only solution to prevent your controlling subsystem from restarting after a full system backup is to change your system startup program system to *NONE, as detailed in the article.
Turning Off the System Attention Light in Other HMC Realities
Regarding my article on turning off the system attention light on Power i, System i, and iSeries boxes, two readers wrote in describing alternate scenarios for turning off the system attention lights by using the Hardware Management Console (HMC).
First, Terry Herrin wrote in to tell me that my HMC technique for turning off the attention light doesn’t work in all cases. Here’s what he said, along with some instructions for how to turn the light off when using other versions of the HMC software:
At the bottom of your articles, you put in a notice regarding the version of i5/OS that you tested the article with. But you may also want to mention what version of HMC software you used in your tests. In your article on the System i Attention Light, your instructions for turning off the System Attention LED are not correct for Version 7 of the HMC. We are running HMC level 7.3.3 here, and the instructions for turning off the LED in that version are:
Note: These instructions were untested before publishing, so there may be some variations when you try to run them on a 7.3.3 HMC machine.
Terry has a point. In future articles, I will note the HMC version and level that I am testing with. So if any other readers are having problems using my HMC instructions to turn off their system attention light, try these instructions and see if they do the job.
In addition to Terry’s contribution, reader J. Brown from Wyoming wrote in with this observation about the relationship between the Thin Console for System i and the system attention light:
If the console is a “thin client” console, and you power off the console, you will also turn on the SA light. IBM tells us it is because the thin console is wired to one of the HMC ports, and if the HMC gets disconnected, this is a serious error. This is even though the thin console is not an HMC, and powering it off should not be any bigger of a deal than powering off a twinax console, IBM tells us they are not going to fix this situation (maybe that is one reason why the “thin console” device is not going to be offered anymore). Outside of this problem, we found that the thin console was a great replacement for a twinax console, when the HMC is not required in your environment (no LPARS are needed). It seems to me that the thin console is a better option than using a PC for the console, but that is just my humble opinion.
According to a recent article on IBM’s April Power i announcements, Big Blue is indeed pulling the plug on its Thin Console for System i as of July 8.
Hard Drive Installation From the Do-It-Yourselfer
After publishing an article about preparing for a disk drive upgrade, reader Richard Shearwood wrote in to talk about his experiences installing the disk drives himself. While, for liability purposes, I usually hire a third-party installer or IBM for installations, it’s interesting to hear how a DIY hard drive installer does his job:
I recently needed to add disk to our system, and in my case I had no downtime at all. Here’s how it went down.
My system unit was full, but my 5095 expansion unit was empty (of disks, at any rate). I powered off the slots I needed and added the IOP and RAID cards, cabled the back plane connectors, and plugged six new disks into the DB1-6 bays. I then closed everything up. I powered on the slots, and the RAID card was assigned to the IOP. I needed a second IOP reset to recognize the disk slots which had been previously attached to a 5712 card (for no good reason).
I then fired up iSeries Navigator and opened the Configuration and Service-→Hardware→Disk units node for my partition. Since my shop has a LAN console, I have a service tools port available and I was able to run the graphical disk tool. I used the Add Disk wizard. Yes, it sounds corny, but I already know how to use the green screen for this, so I thought the wizard would be interesting. This started up RAID on the disks for me (Balanced RAID-5). I then ran the task to add the disks to the ASP and balance the data.
Here’s the thing. It’s MUCH faster to do this with the system up than with the system down in limited paging mode. I guess the whole process took around two to three hours with no downtime and no impact to users. Perhaps if our disks were really, really busy, we would have wanted to run the disk balancing as a separate task using the Start ASP Balance (STRASPBAL) command to reduce the impact on users. But in our case the system coped fine with the extra I/O.
I have to say how much I love hot-add and hot-swap capability in these systems. And LAN console functionality has a useful place in this too, possibly even on Power 5 boxes and higher.
Thanks, Richard, for sharing your adventures in disk drive installation. As always, if anyone reading my articles has any corrections, additions, or plain old stories of i5/OS administrative derring-do, send them over to me through the IT Jungle Contact Web page, and I’ll consider them for publication in a later issue.