Slow rsync on ext4 filesystem

On a rather hefty rsync job between two local ext4 filesystems, writing on the target (a mechanical hard drive which should be able to sustain 100 mb/s) would fluctuate strongly (between 0 mb/s and 160 mb/s) and effectively slow down to a few mb/s on average after a few minutes. While I didn't find the … Continue reading Slow rsync on ext4 filesystem →

Nautilus browsing large windows share is slow

When browsing large windows (samba) shares with Ubuntu Nautilus (that's the equivalent of the Windows File Explorer) I observed that shares which include many files and directories (a few hundred) take a few seconds to browse over WiFi, but almost instantly display over a fast LAN. A similar difference in speed is noticeable when searching … Continue reading Nautilus browsing large windows share is slow →

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 →

Unjam CSS

Abstract: Unjam CSS is a technique for removing render-blocking CSS from pages over which we have only partial control, such as CMS or portals. The problem: a portal generates HTML pages based on a template. Custom HTML can be inserted at specific place holders, but we can't modify the rest of the page HTML. The … Continue reading Unjam CSS →