Tag: Troubleshooting

Mysql: the definition of table prevents operation … on table

This is a tricky one affecting MySql table updates which have views. Documentation about this error actually explains the cause, but doesn't connect the dots. I have a view V on table T and want to delete some rows from T. That works fine as long as the DELETE statement doesn't involve the view, so … Continue reading Mysql: the definition of table prevents operation … on table →

Ubuntu 20.04 getting wrong IP address

Yesterday (early August 2021) my Ubuntu 20.04 installation started configuring all network interfaces (wifi, ethernet) with IPv4 addresses from the wrong network segment block, namely 192.168.0.x. IPv6 still worked fine. I didn't figure out whether that's due to a change in the router or the OS (I suspect the router, because the situation improved when … Continue reading Ubuntu 20.04 getting wrong IP address →

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 →

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 →