Tag: performance

First write operation to large ext4 file system is slow

I'm running a large (>20TB) ext4 file system and noticed that the first substantial write operation after mounting is very slow and involves plenty of drive activity. The reason seems to be some memory structure initialisation as described here: https://linux-ext4.vger.kernel.narkive.com/SUFNE520/ext4-slow-performance-on-first-write-after-mount The workaround is thankfully as simple as running this command in a script after mounting … Continue reading First write operation to large ext4 file system is slow →

HTTP compression and incremental rendering

TL;DR: HTTP compression can delay rendering of web resources HTTP permits content to be served with different encodings, some of which can be used to compress [1] the data volume transferred over the network, which has become a frequent suggestion [2] towards optimising websites for performance. It turns out that the deflation phase of the … Continue reading HTTP compression and incremental rendering →

Formatting USB flash drives for write speed

Flash drives enjoy a reputation for being fast and that certainly goes for high-end models with their elaborate memory controllers and multi-bank layouts. A fundamental "problem" with current flash memory technology is that writing even a single bit of information requires that an entire block of flash memory is reset first [1], which greatly reduces … Continue reading Formatting USB flash drives for write speed →

HTTP: The importance of declaring non-cachable resources as such

It works fine with Chrome and it fails on an Android 2.3 browser - the page is performing an XmlHttpRequest to the server for a resource that just changed for sure and yet it gets back an older version. That's the result of a. the browser assuming a resource is cachable even if no Etag … Continue reading HTTP: The importance of declaring non-cachable resources as such →