Tombstoning on top of Windows Azure Table Store

After command journaling probably the next most effective protection against application logic errors is tombstoning (keeping a copy of the last version of a deleted row). In this article I propose a design for adding tombstoning to Windows Azure Table Store using two tables, a main table and a tombstone table.

This article is part of a series. Click here to see summary and complete list of articles in the series.

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Thoughts on implementing a command journal

I had previously concluded that command journaling (creating a journal of all the external user commands and internal maintenance commands I issue) is really useful for recovering from self inflicted data corruption. In this article I look into the various techniques I can use to implement a command journal so as to trade off between system performance and the journal’s utility in recovery.

This article is part of a series. Click here to see summary and complete list of articles in the series.

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Techniques to Ease Recovering from Self Inflicted Data Corruption

In a previous article I argued that even with the protections Windows Azure Table Store provides for my data I can still screw things up myself and so need to put in place protections against my own mistakes. Below I walk through the three scenarios I previously listed and explain how command journaling, tombstoning and versioning could make recovering from my errors much easier.

This article is part of a series. Click here to see summary and complete list of articles in the series.

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The Limits of Command Journals

In a previous article I argued that I needed some kind of journaling/backup for my Windows Azure Tables in order to make it easier for me to recover from my own screw ups. One type of journaling I suggested was command journaling. In this article I look at the practical limitations of command journals and conclude that while they are (somewhat) useful for notifying users who might have been affected by data corruption they aren’t likely in the general case to be re-playable so their real value is probably less than it might appear.

This article is part of a series. Click here to see summary and complete list of articles in the series.

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Do I need to backup/journal my Windows Azure Table Store?

Windows Azure provides a highly scalable, reliable, fault resistent table store. So in theory my service can dump data into the table store and walk away secure in the knowledge that I’ll get back what I put in and that the data will be there when I need it. So is there any reason I should care about backing up or journaling my Windows Azure Tables? As I argue below the answer is - yes. But the reason isn’t to protect me against Azure’s mistakes, it’s to protect me from myself.

This article is part of a series. Click here to see summary and complete list of articles in the series.

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Chef’s Choice SmartKettle Model 688

I love green tea and its variants such as jasmine and genmaicha. But these teas only taste good to me when made with hot water around 160’s. Anything hotter just turns them into an acid brew. But seriously, sticking a thermometer into a cup to measure the heat just wasn’t working out. I bemoaned the lack of a kettle with a thermostat to save me. Thankfully Wired clued me in to a great solution – the Chef’s Choice SmartKettle Model 688. My wife was nice enough to buy me one, it works great and my green tea tastes outstanding!