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I have forgotten to describe a really handy function when you analyse a crash dump. Solaris has an in-memory buffer for the console messages. In the case you write a crash dump, obviously this messages are written into the crash dump as well.

The Solaris Operating Environment has several functions to enable the user or the support engineer in the case something went wrong. Crash and core dumps are an invaluable resource to find the root cause of a problem. Don´t throw them away without looking at them.

Okay, now you have all this crash and core dumps, it would be nice to do something useful with it. Okay, i show you just some basic tricks to get some insight into the state of a system when it wrote a crash dump.

Solaris has mechanisms to control the behaviour of dump mechanisms. These mechanisms are different for crash and core dumps.

Okay, a dumps are not only a consequence of errors. You can force the generation of both kinds. This is really useful when you want to freeze the current state of the system or an application for further examination.

No software is without errors. This is a basic law of computer science. And when there is no bug in the software (by a strange kind of luck) your hardware has bugs. And when there are no bugs in the hardware, cosmic rays are flipping bits. Thus an operating system needs some mechanisms to stop a process or the complete kernel at once without allowing the system to write anything back to disk and thus manifesting the corrupted state. This tutorial will cover the most important concepts surrounding the last life signs of a system or an application.

As my time allows it, i´m continue to work at the "Less known Solaris Features" book. You can download it here.. There will be no further announcements about the document until it reaches 1.0 . Nevertheless i will announce new versions at my Twitter page.

PS: A little bit short 500 downloads so far ...

It´s far from completion, it needs correction reading, some small tutorials are still missing and almost everything may change until i call this document final. But nevertheless i want you give a preview of the "Less known Solaris Features" pdfbook. 200 pages long. You can download it here.

One of the limitations of Opensolaris 2008.05 will be the missing LiveUpgrade. But ... well ... you have something better. The whole concept of LifeUpgrade was transformed into the future by using the capabilities of ZFS.

Okay, quite often the configuration of a feature or application mandates that the data on the disk doesn´t change while you activate it. Okay, an easy way would be simply unmounting the disk. Okay, that´s possible but then you can´t access the data on the disk at all. You can´t even read from the filesystem, albeit this doesn´t change anything on the disk (okay, as long you´ve mounted the disk with noatime).

Okay, the next installment of the "Less known Solaris Features" series is online. This time i will discuss the feature Point in time copies with AVS. As i have to go through some theory at first, it´s a quite long tutorial. It´s the longest so far. Point-in-time copies are a rather unusual feature for small installations, but they are absolutly essential for many enterprise customers. And when you really think about it, there are many usecases even for small installations.

• Part 1: Introduction
• Part 2: Basics
• Part 3: Independent copy
• Part 4: Dependent copy
• Part 5: Compact dependent copy
• Part 6: Preparation of the test environment
• Part 7: Starting a point-in-time copy
• Part 8: Working with point-in-time copies
• Part 9: Disaster Recovery
• Part 10: Administration
• Part 11: Conclusion

Have fun while trying out the feature!

I hope i gave you some insight into this really interesting feature of Solaris and Opensolaris. There are vast posibilities to use it in your daily use. It´s not limited to desaster recovery or backups. One of my customers uses this tool to create independent copies of their database. They take a snapshot at midnight and export it on a different database server. The rationale for this process: They run some long running analytics with a huge load on the I/O system on this independent copy. By using the copy the analysis doesn´t interfere with the production use of the database. Another customer uses this feature for generating test copies of their production data for testing new software versions. You see, the possibilties are vast and virtually endless.

Okay, there are several administrative procedures with the point-in-time copy functionality. I will describe only the most important ones, as i don´t want to substitute the manal with this tutorial.

The process of syncing master and shadow is bidirectional. You can´t not only update the shadow from the master, you can update the master from the shadow as well. This is a really neat feature for diaster recovery.

We´ve created the point-in-time-copy in the last part of the tutorial, but this is only one half of the story. In this part, we will use the this feature for backup purposes. The procedures are independent from the choosen point-in-time copy mechanism.