RAID + dm-integrity vs bit rot

In Building the perfect, cheap NAS I discuss bit rot which silently kills digital archives; my solution chosen back then builds on parchive which adds in a manual process redundancy to archives. This redundancy can be used to identify and correct bit rot to some extent. The issue with this approach is that it's manual … Continue reading RAID + dm-integrity vs bit rot →

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 →

Ubuntu 20.04 not resolving local network hostnames

An Ubuntu 20.04 laptop installation started not being able to resolve the names of hosts in the same local network. Although the host names were registered with the router, the laptop wouldn't be able to resolve those host names. Surprisingly, neither netbios resolution worked (although nbtscan would find those hosts). The solution is to bypass … Continue reading Ubuntu 20.04 not resolving local network hostnames →

Search multiple PDFs in Linux

What user sjr said on https://stackoverflow.com/questions/4643438/how-to-search-contents-of-multiple-pdf-files find /path -name '*.pdf' -exec sh -c 'pdftotext "{}" - | grep --with-filename --label="{}" --color "your pattern"' \;

md and dm-integrity performance issue

I'm experimenting with protecting the perfect NAS RAID setup against bit rot (silent data corruption in long storage) and recently experimented with dm-integrity towards that end. The idea is to add checksums on the block level to each hard disk so that data corruption shows up as an I/O error to md, which would then … Continue reading md and dm-integrity performance issue →