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 →

Ubuntu on the Acer Nitro 5

[updated May 2020] The Acer Nitro 5 is an interesting breed; decent computing power, a mid-range SSD, a large screen with high contrast, a decent and solid keyboard with good haptics at an ok price - but will it run Ubuntu? The Nitro comes with Windows 10 home pre-installed and UEFI secure boot enabled - … Continue reading Ubuntu on the Acer Nitro 5 →

Resetting a PCI device

The Wi-Fi adapter on my VivoBook 17 has been acting up under Ubuntu 18.04 LTS insofar that at a random point in time, possibly accelerated by power saving features, the Wi-Fi will stop working with suspicious syslog entries: ath10k_pci 0000:03:00.0: failed to wake target for read32 at 0x0003a028: -110 The usual tricks (suspend/resume, reload driver, … Continue reading Resetting a PCI device →

A crazy server recovery

If you're a seasoned server administrator then this post will boring beyond oblivion to you; the ingredients: a headless server (no screen, keyboard)years of personal backups on a linux software RAIDa botched system upgradehappy ending The pretext Several years ago I bought an HP Proliant microserver on discount and set up a NAS with Ubuntu … Continue reading A crazy server recovery →

parchive: protecting backups against data corruption

As time goes by, my [place appropriate interval] backups may not grow much, but the size of my entire data archive exceeds the largest available hard disks (don't ask). Taking into account correctness guarantees by hard disk manufacturers, transmission errors over the network and who knows what else, I don't feel confident that I'll flip … Continue reading parchive: protecting backups against data corruption →

Ubuntu on the ASUS VivoBook 17

Following the proud tradition [1],[2],[3] of documenting Linux installations on all the hardware I break, I'm happy to report that Ubuntu 18.04 works fine on the ASUS VivoBook 17 (model number X705U). Things I tested and that work: OS boots from USB and from harddisk Secure boot WLAN USB On board and external (USB) camera … Continue reading Ubuntu on the ASUS VivoBook 17 →

Thunderbird forgetting passwords

After a simultaneous Thunderbird upgrade and profile migration from Windows to Linux the mail program permanently forgets passwords. The setting: Thunderbird 52 on Windows Back up profile Restore profile to Thunderbird 60 on Linux Observe that all passwords to all accounts are lost even if entered again This seems to be some … Continue reading Thunderbird forgetting passwords →

Ubuntu 16.04 LTS on the Acer Aspire E15

I have been moderately content [1] with Ubuntu 14.04 on the Acer Aspire E15 for about a year. Ubuntu 16.04 LTS, another long term support release, has recently been published and of course I had to try it out! Installing the live image on a USB stick: bring some patience The first obstacle is that … Continue reading Ubuntu 16.04 LTS on the Acer Aspire E15 →

Ansible local_action privilege de-escalation or: how to wait for a reboot

I increasingly use Ansible not only for glorious tasks like setting up my various VMs I use for prototyping but also for mundane things like resetting my personal laptop every time I get a new one or break it (dedicated readers of this blog will know me to do that a lot [2],[3],[4]). Most of … Continue reading Ansible local_action privilege de-escalation or: how to wait for a reboot →

Securing a development server

In this post I talk about setting up and securely operating development tools like Jenkins and Gitlab on a server connected to the internet. All applications run behind a firewall and a reverse HTTP proxy which allows only HTTP requests from selected users through who authenticate themselves with client certificates. Putting web-facing software on the … Continue reading Securing a development server →