n0derunner

Multiple devices/jobs in fio

Published: (Updated: ) in fio, , by .

If your underlying filesystem/devices have different response times (e.g. some devices are cached – or are on SSD) and others are on spinning disk, then the behavior of fio can be quite different depending on how the fio config file is specified.  Typically there are two approaches 1) Have a single “job” that has multiple […]

Here be Zeroes

Published: (Updated: ) in Debugging, , by .

Many storage devices/filesystems treat blocks containing nothing but zeros in a special way, often short-circuiting reads from the back-end.  This is normally a good thing but this behavior can cause odd results when benchmarking.  This typically comes up when testing against storage using raw devices that have been thin provisioned. In this example, I have several […]

Designing a scaleout storage platform.

Published: (Updated: ) in Nutanix, , by .

I was speaking to one of our developers the other day, and he pointed me to the following paper:  SEDA: An Architecture for Well-Conditioned, Scalable Internet Services as an example of the general philosophy behind the design of the Nutanix Distributed File System (NDFS). Although the paper uses examples of both a webserver and a gnutella client, […]