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Cake day: June 2nd, 2023

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  • Not sure what you’re trying to ask, are you asking if using sudo to sign in as a different user will make kernel updates take effect? If so, the answer is no.

    Linux is an operating system kernel, which basically means it’s a program which runs other programs inside of it. For any “normal” program running inside Linux, you can update it by installing the new version and then exiting and relaunching the program so that the installed updates take effect. Similarly, after installing the Linux kernel itself, you have to exit and restart the kernel in order for the update to take effect. Because the kernel runs programs inside of it, exiting the kernel means all of those programs will be exited as well, and because the kernel is the only program running directly on the hardware, exiting the kernel means that your computer will power off. In simpler terms: getting kernel updates to take effect necessarily means you need to exit the old kernel and launch the new one, and there is no way to do that without reboot.




  • Just chiming in to point out that powering off and then starting back up won’t cause any additional SSD wear, reading from flash memory doesn’t use up write cycles* (because there is no writing going on!). In fact, regularly restarting could be slightly more friendly for your SSD, because the /tmp directory, old log files, etc. get deleted on startup, freeing up the storage blocks used by the deleted files so that the SSD can use them for its internal wear balancing.

    *technically, flash memory reads do very slightly degrade the data being read, but this effect is absolutely negligible compared to other forms of passive bit rot in flash memory and is basically irrelevant unless you’re intentionally trying to corrupt data using reads (which won’t happen because the flash controller will fix it before it becomes corrupt to the point of being illegible)

















  • You’ve made me uncertain if I’ve somehow never noticed this before, so I gave it a shot. I’ve been dd-ing /dev/random onto one of those drives for the last 20 minutes and the transfer rate has only dropped by about 4MB/s since I started, which is about the kind of slowdown I would expect as the drive head gets closer to the center of the platter.

    EDIT: I’ve now been doing 1.2GB/s onto an 8 drive RAID0 (8x 600GB 15k SAS Seagates) for over 10 minutes with no noticable slowdown. That comes out to 150MB/s per drive, and these drives are from 2014 or 2015. If you’re only getting 60MB/s on a modern non-SMR HDD, especially something as dense as an 18TB drive, you’ve either configured something wrong or your hardware is broken.