New script for setting up multipath.conf entries

I've added a new script to the Useful Scripts page called setup-violin-mpath.sh which automates the process of creating entries for the /etc/multipath.conf file on Red Hat 6 / Oracle Linux 6. As the name suggests, I wrote it with Violin devices in mind, but there should be overlap with other storage which will potentially make … Continue reading New script for setting up multipath.conf entries →

Oracle Fixes The 4k SPFILE Problem…But It’s Still Broken

As anyone familiar with the use of Oracle on Advanced Format storage devices will know to their cost, Oracle has had some difficulties implementing support of 4k devices. Officially, support for devices with a 4096 byte sector size was introduced in Oracle 11g Release 2 (see section 4.8.1.4 of the New Features Guide) but actually, if the … Continue reading Oracle Fixes The 4k SPFILE Problem…But It’s Still Broken →

Playing The Data Reduction Lottery

Cluttered office desk with scattered papers, notebooks, stationery and a used coffee cup, centred around a brightly coloured lottery ticket reading “WIN MILLIONS” and “Jackpot Could Be Worth Millions,” sharply in focus under warm lighting

Flash vendors routinely quote “effective capacity” figures based on optimistic data reduction assumptions – understanding what those numbers really mean is essential before signing a purchase order.

Oracle Exadata X4 (Part 2): The All Flash Database Machine?

This article looks at the new Oracle Exadata X4-2 Database Machine from Big Red. In part one I looked at the changes made from the X3 model (more stuff) as well as the implications (more license bills). I also covered some of the confusing and bewildering descriptions Oracle has used to describe the flash capacity … Continue reading Oracle Exadata X4 (Part 2): The All Flash Database Machine? →

Predictions for 2014: DataBase-as-a-Service

It's that time of year again where lots of people write articles which begin with the words "It's that time of year again..." and make endless references to crystal balls, tea leaves and the benefits of hindsight. But not me, I'm not descending into cliché. Apart from that first sentence, which with the benefit of … Continue reading Predictions for 2014: DataBase-as-a-Service →

Oracle Exadata X4 (Part 1): Bigger Than It Looks?

One of the results of my employment history is that I tend to take particular interest in the goings on at a certain enterprise software (and hardware!) company based in Redwood Shores. I love watching Oracle's announcements, press releases, product releases and financial statements to see what they are up to - and I am … Continue reading Oracle Exadata X4 (Part 1): Bigger Than It Looks? →

Storage Myths: Storage Compression Has No Downside

Compacted red junk car crushed into a dense cuboid block on a wooden pallet inside an industrial warehouse, with twisted metal, exposed wheel sections, and visible headlight fragments

Storage-level compression trades capacity for CPU cycles and read latency – understanding that trade-off matters more than the headline reduction ratios vendors put in their datasheets.

Storage Myths: Dedupe for Databases

Row of identical yellow rubber ducks, illustrating the concept of data deduplication

Data deduplication promises capacity savings, but databases are one of the worst use cases for it – the technology’s assumptions break down against the entropy and I/O patterns of database workloads.

Understanding Disk: Over-Provisioning

Rows of servers inside a large enterprise data centre

When performance capacity drives storage decisions, waste is the inevitable result – stranded terabytes, short-stroking, and a growing gap between what disk holds and what it can actually deliver.

Understanding Disk: Mechanical Limitations

Table showing CPU performance growth versus disk drive performance growth from 1987 to 2004

Spinning disk hit its performance ceiling at 15k RPM over two decades ago – and physics, aerodynamics and economics mean it’s staying there. The consequences for latency are unavoidable.