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The Fundamental Characteristics of Storage
Storage for DBAs: As a rule of thumb, pretty much any storage system can be characterised by three fundamental properties: Latency is a measurement of delay in a system; so in the case of storage it is...
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Strange ASM Behaviour with 4k Devices
This is only a short post to document something I’ve seen and reproduced but still don’t understand. Storage devices generally have a physical sector size of 512 bytes or, more recently, 4k. This is a...
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Understanding I/O: Random vs Sequential
Storage for DBAs: Ever been to one of those sushi restaurants where the food comes round in dishes on a conveyor belt? As each dish travels around the loop you eye it up and, as long as you can make...
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Does My Database Need Flash?
Storage for DBAs: Here’s a question I get asked a lot: “Does my database need flash?”. In fact it’s the most common question customers have, followed by the alternative version, “Does my database need...
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The Most Important Thing You Need To Know About Flash
Storage for DBAs: There are many things you need to know about flash: it’s performance, it’s behaviour, it’s durability etc. But there’s one single piece of information which tells you more than...
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SLOB2: Essential for Every DBA Toolkit
A couple of weeks ago, Kevin released the second version of SLOB – the Silly Little Oracle Benchmark. Readers will know that I was already a big fan of the original version, but version 2 (which I was...
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SLOB: PL/SQL Commit Optimization
I ran some SLOB tests over the weekend using the new SLOBv2 kit and noticed some interesting results. I was using SLOB to generate physical I/O but the “anomaly” is best demonstrated by putting SLOB in...
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New SLOB2 Physical I/O Harness
Short post to point out that I’ve now posted the updated PIO Test Harness for SLOB2. This can be used to run multiple SLOB tests with varying numbers of workers and values of UPDATE_PCT. In addition...
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SLOB2: Testing The Effect Of Oracle Blocksize
I recently posted a test harness for generating physical I/O using the new version of SLOB (the Silly Little Oracle Benchmark) known as SLOBv2. This test harness can be used for driving varying...
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The Role Of The DBA
I’m back at work today after a week’s travelling around Europe followed by a week’s holiday sailing around the Ionian Sea. I have to say that I’d rather still be on holiday. It’s not that I don’t...
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Storage Myths: IOPS Matter
Storage for DBAs: Having now spent over a year in the storage industry, I’ve decided it’s time to call out an industry-wide obsession that I previously wasn’t aware of: everyone in storage is obsessed...
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7 Steps to Guarantee People Will Read Your Posts
I see this type of article pop up all the time on places link LinkedIn and SlideShare. Here’s my response… Chess is a suitably abstract subject and so can seem relevant to anything Choose an arbitrary...
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Storage Myths: Put Oracle Redo on SSD
Storage for DBAs: “My database is slow”… “Well then why not put your redo logs on SSDs?” Gaaaah. I still hear people having this discussion and it drives me mad. “Nobody got fired for putting Oracle...
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The Real Cost of Enterprise Database Software
Storage for DBAs: The strange thing about enterprise databases is that the people who design, manage and support them are often disassociated from the people who pay the bills. In fact, that’s not...
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The Real Cost of Oracle RAC
Storage for DBAs: In my previous article (in this mini-series on understanding Oracle licensing costs) I explained how to calculate the cost of a mid-range Oracle database system. My motive was a...
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OOW13: The Future Is Here (Just Don’t Mention “Legacy”)
Last week I attended Oracle OpenWorld 2013 in the stunning city of San Francisco, along with 60,000 other attendees. At times it felt like we’d taken over the entire city, with every street, bus,...
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The Most Expensive CPUs You Own
Take a look in your data centre at all those humming boxes and flashing lights. Ignore the storage and networking gear for now and just concentrate on the servers. You probably have many different...
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Understanding Disk: Superpowers
It’s a familiar worn-out story. A downtrodden and oppressed population are rescued from their plight by a mysterious superhero. Over time they come to rely on this new superbeing – taking him for...
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Understanding Disk: Mechanical Limitations
The year 2000. Remember that? The IT industry had just spent years making money off the back of the millenium bug (which turned out not to exist). The world had spent even more money than usual on...
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Understanding Disk: Over-Provisioning
Image courtesy of Google Inc. In a recent news article in the UK, supermarket giant Tesco said it threw away almost 30,000 tonnes of food in the first half of 2013. That’s about 33,000 tons for those...
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