One of the things that repeatedly seem to puzzle users about the DRBD is the question of whether to use internal or external metadata. Remember, DRBD sets aside a small area on a local disk (on every cluster node) where it keeps the Activity Log, the quick-sync bitmap, data generation UUIDs, and a few other bits and pieces for local housekeeping.
The specific aspect that is to be discussed here is the Activity Log. Without going into too much detail, let’s be satisfied with the factoid that DRBD[Read more...]
As someone may have noticed, I recently wrote a trilogy on how to dive into the MySQL Cluster source code. Unfortunately my overtures towards the MySQL Cluster source code ended up being only a look-but-don't-touch affair, as I failed to actually get to touch her internals with my text editor. Even so, in this post I'd like to tell about the background to my love affair with this beauty, by relating to some benchmarks I've been working on together with my customers.
Oh, and I'd like to apologize already, that I cannot mention where these benchmarks were done, what the schema looked like and the exact numbers. If you want that kind of real benchmarks, you should read Mikael's blog, or watch the slides from this webinar[Read more...]
This is part II of my efforts to prove myself that I can do programming. In part one I successfully created a MySQL Cluster branch for myself and compiled it.
Let's go to the public MySQL bug database and see if there are any trivial MySQL Cluster bugs I could sharpen my teeth on. Heh, sure enough #32658 looks simple enough. There is a typo in an output string - so I could fix that without even doing any C++ code! (Funnily, a MySQL internal comment to the bug says something about it being embarrassing. Guess it is a good bug for me then, as patching over embarrasments is what Sales Engineers do routinely :-)
Let me see...
My collagues Anders and even Ivan sometimes blog about the grandeur of being a Sales Engineer. And I agree, it is a great job, probably the best I ever had, so far. But let me share a secret: It's not as technical as you'd think. Sure, they call me a "pre-sales consultant" alright, but I would be ashamed of comparing my own work with those of the real consultants. I sometimes jokingly say that the most amazing technical things in my job are airplanes (they fly in the air!) and how to make a nice slideshow. (OpenOffice Impress sucks btw, and I always envy my OS X + Keynote using friends on this one[Read more...]
By popular demand, we are now offering an on-line incarnation of our DRBD Total training sessions, normally taught in a 4-day on-site course. The next such training commences on May 18 (next Monday), and we still have a few seats left — so if you’re interested, grab one while you still can!
Here is an overview of the course highlights:
Every course attendee gets a virtual[Read more...]
Both DRBD and Dolphin Express already being a fixture in the MySQL (http://www.mysql.com) universe, this webinar should be particularly interesting to those of you who want to minimize database write latency while maintaining fully redundant and transaction-safe high availability. However, it’s also a must see for virtualization and mail service DRBD users, who also typically have a need for low latency.
This is, of[Read more...]
I’ve been asked by a number of people on how to do an upgrade from DRBD version 0.7 to DRBD 8. This upgrade does necessitate some minimal service down time, but it’s really not rocket science. And no, it does not force you to sync all of your data all over again.
Here’s my quick write-up.
Do not, I repeat do not attempt your upgrade unless you have at least read this blog entry to the finish.
First, you need to make sure that you have both your DRBD 8 userland binaries and kernel module ready to install. For our support customers, this means that you simply download two RPMs (or .debs) from our support web site. Make sure you have the right packages; you want those that match your system architecture and (for the kernel module) also your running[Read more...]