Edit: I still wonder about keeping a spare water heater on hand
Originally published by TechChannel July 30, 2021
Rob McNelly on VIOS admin tips, OpenSSH for AIX, effective support and more
Recently my water heater died. Fortunately it’s relatively new and still under warranty, so I didn’t have to dip into my pockets to get it repaired. But I did have to wait, because the manufacturer needed to ship a part, which took a few days.
Supply chains are still being stretched, so it wasn’t surprising to learn that the required part wasn’t available in my area. Since I live in Phoenix, having to take a few showers in lukewarm water isn’t the worst thing this time of year, but still, what’s the point of a manufacturer’s warranty if my issue can’t be promptly resolved?
With all the camping I do, I’ve collected quite a bit of equipment over the years. A lot of this gear, like cots and sleeping bags and air mattresses, serves to keep me warm and comfortable. Given that I also have a 12-volt fridge with sufficient batteries to run it, not to mention a vehicle with a generator and an AC unit, one could argue that I’m more of a “glamper.” But having options, based on where you’re going and what you’re doing, is important. My point though is that during this recent stretch, I considered deploying one of my favorite camping comforts at home: a portable tank-less water heater.
While I don’t have this exact system, you get the idea. It’s great when you want to clean up at the end of a hot, sweaty, dirty day in the back country, but it doesn’t have much use in the house. It’s not an option to warm water for the dishwasher or washing machine. And as I said, with Arizona summers being what they are, I can get by without hot showers for now.
I must admit, even though it was just a few days, I missed the luxury of instant hot water. I’m sure my grandparents wouldn’t skip a beat without the convenience of an on-demand, whole house water heater. But me, the rugged outdoorsman? I was reminded how soft I am living in this modern world.
Anyway, to put a tech spin on this, I liken it to having a bares-bones disaster recovery solution. My little water heater is like a small backup box that will get me by in a pinch. By comparison, my regular home water heater is a powerful production machine that gives me everything I need to handle my water workload.
Would it make sense to purchase a second full size backup water heater, just in case I needed it? No. After all I’m not using my hot water to make money or service my customers, and it’s not as if I could lose millions for every minute without hot water. But the calculation is the same. What’s the cost of downtime? How valuable is continuous availability?
The part eventually arrived. In hindsight, it may have been faster had the manufacturer simply replaced my broken water heater. Of course from their perspective, shipping a single part is easier and cheaper. So I guess I come away from this episode with even greater appreciation for IBM support. Because when I need computer parts for a server, IBM generally ships and installs them promptly. Another advantage is that more times than not, my server will proactively call home. On occasion it’s actually IBM that lets me know when a part is failing and must be replaced. I sure wish my water heater could call home.
OpenSSH for AIX: What’s New
Chris Gibson has a nice write-up about the new features available with the latest version of OpenSSH for AIX:
The latest version of OpenSSH for AIX 7.2 now supports POWER9 HW GZIP! The requirements for this new capability are as follows:
- Processor mode: Power9 (instead of Power9_Base)*
- AIX Level: 7.2 TL 4 and above*
- zlibNX: 7.2.4.0 NX accelerated zlib compression library*
- OpenSSH version: 8.1.102.2102 and above*
- OpenSSL version: 1.0.2.2100 and above *
- ssh commands (like ssh, scp etc) should be run with -C option (compression enabled)
Read the whole thing to get the details.
Assessing Your Options With FLRT Lite
Off the top of your head, do you know if a POWER7 server will run VIOS 3.1.2.21?
Start by consulting FLRT lite and searching on VIOS. As of this writing, the current VIOS version recommendation is 3.1.2.21.
Then check the VIOS lifecycle information. Version 2.2 has reached end of support, while the projected end of support for 3.1.2.x is November 2023.
I mention POWER7 specifically because a client with that system was wondering about their options. If you go to FLRT and plug in 8202-E4C for the machine type model, you’ll see that 2.2.6.5 is the latest recommended version of VIOS code. For an 8202-E4D model (POWER7+), the recommendation is 3.1.2.21.
What would you do in this situation? Is there enough of a difference between POWER7 and POWER7+ that you would hesitate to deviate from the recommendations? In this case, even when told by support to stand pat, the client was brave and chose to install 3.1.2.21 on their POWER7 box, because that version of VIOS is still supported. It worked. Of course every environment is unique, so your mileage may vary. And ultimately, getting to POWER9 should be your goal if it is at all possible. But I can report that at least one client is now successfully running 3.1.2.21 on POWER7.
VIOS Admin Tips
I want to again plug the Power Virtual User Group (VUG) technical webinar series. Last month I cited Nigel Griffiths’s first look at the POWER9 HMC, but there’s another excellent presentation from back in May that I neglected to mention. It’s Jaqui Lynch’s deep dive on VIOS:
Session 106: VIOS—Top Tips for Successful Administration
Speaker: Jaqui Lynch, Information Architect, AIX & Linux Performance Consultant, IBM Power Champion
VIO servers are the most critical part of your system setup. If they are not happy, then no client LPAR is happy. This session provides tips on setting up and maintaining VIO servers including upgrades and patching. Backup and recovery are also covered.
Be sure to download the slides and listen to the replay. As always, she has some great information. Her recent TechChannel article on this topic is also worth your time.