For some time now I have preferred Oracle SLOB as my tool for generating I/O workloads using Oracle databases. I've previously blogged some information on how to use SLOB for PIO testing, as well as shared some scripts for running tests and extracting results. I've now added a whole new landing page for SLOB and … Continue reading New section: Oracle SLOB Testing
Category: Flash
Understanding Flash: SLC, MLC and TLC
SLC, MLC and TLC NAND flash differ in how many bits each cell stores. More bits per cell means lower cost and higher density – but slower performance and reduced endurance. This article explains the trade-offs for enterprise storage.
Understanding Flash: Blocks, Pages and Program / Erases
NAND flash memory stores data in pages but erases in blocks – a fundamental asymmetry that shapes everything from SSD performance to all-flash array design. This article explains the program/erase cycle and why it matters for database storage.
New My Oracle Support note on Advanced Format (4k) storage
In the past I have been a little critical of Oracle's support notes and documentation regarding the use of Advanced Format 4k storage devices. I must now take that back, as my new friends in Oracle ASM Development and Product Management very kindly offered to let me write a new support note, which they have … Continue reading New My Oracle Support note on Advanced Format (4k) storage
Understanding Flash: What Is NAND Flash?
NAND flash memory was invented in 1981 by Dr Fujio Masuoka at Toshiba. This article explains how flash works, why it differs from EPROM and EEPROM, and why program and erase operations behave differently.
The Ultimate Guide To Oracle with Advanced Format 4k
It's a brave thing, calling something the "Ultimate Guide To ..." as it can leave you open to criticism that it's anything but. However, this topic - of how Oracle runs on Advanced Format storage systems and which choices have which consequences - is one I've been learning for two years now, so this really … Continue reading The Ultimate Guide To Oracle with Advanced Format 4k
New installation cookbook for SUSE Linux Enterprise Server 11 SP3
Exactly what it says on the tin, I've added a new installation cookbook for SUSE 11 SP3 which creates Violin on a set of 4k devices. I've started setting the add_random tunable of the noop I/O scheduler because it seems to give a boost in performance during benchmarking runs. If I can find the time, I … Continue reading New installation cookbook for SUSE Linux Enterprise Server 11 SP3
Postcards from Storageland: Two Years Flash By
The start of March means I have been working at Violin Memory for exactly two years. This also corresponds to exactly two years of the flashdba blog, so I thought I'd take stock and look at what's happened since I embarked on my journey into the world of storage. Quite a lot, as it happens... … Continue reading Postcards from Storageland: Two Years Flash By
Oracle AWR Reports: Understanding I/O Statistics
One consequence of my job is that I spend a lot of time looking at Oracle Automatic Workload Repository reports, specifically at information about I/O. I really do mean a lot of time (honestly, I'm not kidding, I have had dreams about AWR reports). One thing that comes up very frequently is the confusion relating … Continue reading Oracle AWR Reports: Understanding I/O Statistics
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
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