etbe – Russell Coker

Almost two years ago I blogged about a strange performance problem with SATA disks [1]. The problem was that certain regions of a disk gave poor linear read performance on some machines, but performed well on machines which appeared to be identical. I discovered what the problem was shortly after that but was [...]

I have just released version 1.03e of my Bonnie++ benchmark [1]. The only change is support for direct IO in Bonnie++ (via the -D command-line parameter). The patch for this was written by Dave Murch of Violin Memory [2]. Violin specialise in 2RU storage servers based on DRAM and/or Flash storage. [...]

I’ve just started work on a new HP server running RHEL5 AS (needs to be AS to support more than 4 DomU’s). While I still have the Xen issues that made me give up using it on Debian [1] (the killer one being that an AMD64 Xen Dom0 would kernel panic on any serious [...]

I have just been running some ZCAV tests on some new supposedly 1TB disks (10^40 bytes is about 931*2^30 so is about 931G according to almost everyone in the computer industry who doesn’t work for a hard disk vendor).
I’ve added a new graph to my ZCAV results page [1] with the results.
One interesting thing that [...]

The way Xen works is that the RAM used by a virtual machine is not swappable, so the only swapping that happens is to the swap device used by the virtual machine. I wondered whether I could improve swap performance by using a tmpfs for that swap space. The idea is that as [...]

Today I released new versions of my Bonnie++ [1] benchmark. The main new feature (in both the stable 1.03b version and the experimental 1.93d version) is the ability of zcav to write to devices. The feature in question was originally written at the request of some people who had strange performance results when [...]

As correctly pointed out by cmot [1] my previous post about software RAID [2] made no mention of bus bandwidth.
I have measured the bus bottlenecks of a couple of desktop machines running IDE disks with my ZCAV [3] benchmark (part of the Bonnie++ suite). The results show that two typical desktop machines had significant [...]

Dear lazyweb, I want to design T-Shirts for my Bonnie++ and Postal projects. But representing those projects in a picture seems more difficult than SE Linux (see one of my SE Linux T-Shirt designs below). If you have any conceptual design ideas then please let me know.
Here are my current designs for SE [...]

Below is a GNUPlot graph of ZCAV output from a 250G SATA disk. The disk has something wrong with it (other disks of the same brand in machines of the same configuration give more regular graphs). The expected graph will start high on the Y scale (MB/s) and steadily drop as the reads [...]

This paper by Rodney Van Meter about ZCAV (Zoned Constant Angular Velocity) in hard drives is very interesting. It predates my work by about four years and includes some interesting methods of collecting data that I never considered.
One interesting thing is that apparently on some SCSI drives you can get the drive to tell [...]