It has taken me a while to fully understand the difference between HADR_TIMEOUT and HADR_PEER_WINDOW. I think there is some confusion here, so I’d like to address what each means and some considerations when setting them. In general, you’ll only need HADR_TIMEOUT when using HADR and only need HADR_PEER_WINDOW when using TSA(db2haicu) or some other automated failover tool.… Read the restContinue reading »
Tag: High Availability
High Level Overview of Reads On Standby
With DB2 9.7 Fixpack 1, IBM started supporting reads on the HADR standby. This was a bit of an exciting feature for some of us. But in practice there are enough restrictions that it ends up not being an option that many clients choose.… Read the restContinue reading »
When is a Reorg Really Online?
We bandy about the term “online” reorg. But you’d be surprised how often there are issues with that. IBM officially calls it an “INPLACE” reorg. Read on to understand exactly when it is fully online and when it is not.
When we first got our hands on online reorgs, it seemed like the “INPLACE” keyword was all we needed, and we had availability during reorg – that any they required less disk space at one time.… Read the restContinue reading »
IDUG NA 2013 Brain Dump
Wait, don’t avoid reading this because you didn’t go to the conference. There is still valuable stuff here. In fact, it is even more valuable for those who did not go. Last year, I posted my brain dump by basically re-writing all of my paper notes.… Read the restContinue reading »
TSA/db2haicu error and resolution
Especially with TSA and db2haicu, sometimes you see an error, and you have a bag of tricks that you try, even though you don’t understand exactly why they work. In this case, I had a brand-spanking-new server, with DB2 installed the very same day, and no matter what I did, db2haicu would fail on creating the domain with this error message in the diag.log:… Read the restContinue reading »
Using TSA/db2haicu to automate failover Part 4: Dealing with Problems After Setup
Updated March 2019 with the command to get the first output
Most of what you’ll need to set up and test TSA using db2haicu is in my first few posts on the topic:
Using TSA/db2haicu to automate failover – Part 1: The Preparation
Using TSA/db2haicu to automate failover – Part 2: How it looks if it goes smoothly
Using TSA/db2haicu to Automate Failover Part 3: Testing, Ways Setup can go Wrong and What to do.… Read the rest
“Now, now you two play nice” … DB2 and HACMP Failover
The holy grail of I/T is to be up all the time with no user impact. As most companies mature in the I/T area there is a shift from reactive tactics to proactive measures. There is a strong desire to be an industry leader and adhere to a “Five 9’s” mentality.… Read the restContinue reading »
Guest Bloggers Next Week!
The week of December 17th, I’ll be welcoming guest bloggers once again. Mike Krafick, who did a couple of guest blogs for me earlier in the year (10 Minute Triage: Assessing Problems Quickly (Part 1) and 10 Minute Triage: Assessing Problems Quickly (Part 2)) is teaming up with a great SA to bring us great details on using DB2 with HACMP.… Read the restContinue reading »
When Both HADR Servers are Rebooted at the Same Time, DB2 Won’t Work
I have a client that has been having some issues that cause both HADR servers to go down at the same time. Ignoring for the moment that it’s a bad idea to share resources that can cause this to happen, they seem frustrated that when both servers come back up, DB2 does not automatically come back up.… Read the restContinue reading »
Three HADR Failures
When you move DB2 servers from one hosting provider to another, you have to re-do hadr. Along with another DBA, I had 6 production databases across 3 instances to move last Saturday night, along with the HADR databases. The entire change had been tested ahead of time at least once, and probably more like 3 times, with no hiccups.… Read the restContinue reading »
How to Disable ASLR and Why you Should do it
Update: Oct 28, 2013 – the below applies only to DB2 before DB2 10.1 Fixpack 3. IBM says that ASLR can safely be used with DB2 on 10.1 Fixpack 3 and later. See the technote at http://www-01.ibm.com/support/docview.wss?uid=swg21365583. FixPack 3 was released on September 27th.… Read the restContinue reading »
Using TSA/db2haicu to Automate Failover Part 3: Testing, Ways Setup can go Wrong and What to do.
Part 3 in this series is a bit overdue. Parts 1 and 2 were back in April. This is a complicated topic. Please use any procedures here with extreme care, and keep in mind that if you have anything other than the standard two-server HADR-only TSA implementation, these procedures probably aren’t the best idea, as they could break other things.… Read the restContinue reading »