TIL

Today I learned (TIL) entries.

2024-12-13: WAL and durability

Today I read an in­ter­est­ing blog post by Phil Eaton about write-​ahead logs and dura­bil­ity.

Check it out here.

•  databases

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2024-12-11: Deterministic simulation testing

Today I learned about de­ter­min­is­tic sim­u­la­tion test­ing, an ap­proach to test dis­trib­uted sys­tems. The core idea is to re­move all non-​deterministic be­hav­ior from the crit­i­cal parts of the ap­pli­ca­tion, cre­at­ing a con­trolled en­vi­ron­ment where the se­quence of events can be ma­nip­u­lated.

This in­volves set­ting fixed seeds for ran­dom num­ber gen­er­a­tors, con­trol­ling clock and time de­pen­den­cies, run­ning tests in a sin­gle thread, and using asyn­chro­nous I/O op­er­a­tions. While these con­straints might seem overly re­stric­tive, they allow us to re­pro­duce bugs found dur­ing sim­u­la­tions.

It’s eas­ier said than done, though. Adding this kind of test to an ex­ist­ing sys­tem can be chal­leng­ing. There’s al­ways going to be some non-​deterministic edges. Also, the test is only as good as your sim­u­la­tion.

Read more in this blog post.

•  distributed-systems

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2024-11-07: LUKS with USB unlock

I’ve been using Linux Uni­fied Key Setup (LUKS) for full disk en­cryp­tion on my home server, but en­ter­ing a long pass­word on every boot can be quite in­con­ve­nient. That’s why I was search­ing for a way to use a key file in a USB stick to un­lock the root par­ti­tion.

There are many blog posts and re­sources on how to do it, but many are out­dated and none of them al­lowed me to enter the pass­word if the key is not avail­able. This can lead to mount fail­ure dur­ing boot, which is ex­tremely in­con­ve­nient for a head­less com­puter.

For­tu­nately, I stum­bled upon a blog post which de­scribes a way to do what I wanted!

Read it here: https://tqdev.com/2022-​luks-​with-​usb-​unlock

•  security
•  home-server

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