I’m moving large-ish (half-TB or larger) files between hosts. It’s important to avoid extra copies in this workflow, since each pass over one of the larger files to read the whole thing (and there are several of them) takes hours. I managed to decrypt VM disk images, transform them from one disk image format to another, copy them from one host to another, calculate SHA-256 hashes on both sides to verify data integrity, compress and encrypt them on the destination, and to display a progress bar, all without any additional copies. One big block-device read on the source end and one big block-device write on the destination end is all of the disk I/O that’s happening.
See below for how I did this.
Continue reading “Minimizing I/O when migrating from Virtualbox on Veracrypt to Proxmox on ZFS”
I’m doing software development on an Ubuntu 20.04 VM running on my MacBook Pro via Parallels Desktop 17. I recently noticed that the “Software Update” app in the Ubuntu desktop machine was saying there were a lot of things to update, which makes sense since I just created this VM a couple of months ago via a fancy Ansible playbook, and I haven’t gotten around to updating it until yesterday.
Well, after the update, it started taking a really long time to boot. There were two places where it hangs for 2 minutes for no apparent reason, meaning that the boot process is about 4-1/2 minutes long.
I’ve figured out what happened and found a workaround, but I’ll mention a few of the things I looked at along the way since they’re sort of interesting and may be relevant if your issue is similar but not caused by the same thing.
Continue reading “Solved: Ubuntu 20.04 update makes boot time increase by 4 minutes”
Argh! I spent about 5 hours yesterday troubleshooting a failed Ubuntu Jaunty -> Karmic (9.04->9.10) upgrade. It worked fine until I rebooted and then failed to boot. Here’s how I fixed it.
Continue reading “Karmic on Xen with Bad /etc/fstab = PAIN”
Once again Ubuntu Linux proves itself to be easy to upgrade. Going from 9.04 to 9.10 (one release newer, since their numbering is bsaed on dates) was easy, but included the standard sprinkling of manual re-customization that I’ve come to expect from Debian based systems.
Continue reading “Ubuntu 9.10 (Jaunty Jackalope) upgrade notes”
I’m working on a Rails app that uses the ym4r_gm plugin, getting Google to do the geocoding for Thentic. I liked the idea of stubbing the web service call, because all those calls to an external service add up to over 20 seconds of test suite run time(!). That’s almost half of the 50 second run time of my unit tests (and 50 seconds is much too long for a unit test suite).
I found a good starting point at geokit stubbing for faster tests. I also wanted a way to stub a geocoding failure, and a way to prevent any unit tests from using the real geocoding web service.
Here’s how I did it.
Continue reading “Fancier Stubbing of GeoKit for Rails unit tests”