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> when I upgrade, everything will keep working FreeBSD doesn't promise compatibility between major versions, it's a breaking change, e.g. in FreeBSD 12 they re

> when I upgrade, everything will keep working FreeBSD doesn't promise compatibility between major versions, it's a breaking change, e.g. in FreeBSD 12 they revamped some system types and like half of system interface became incompatible with FreeBSD 11.

toast0 5y ago
It depends on the specifics, but if you install the -compat packages and enable the compat kernel flags, broadly speaking old software continues to work across major versions. Anyway, just because I expect it to happen, doesn't mean it happens (and I acknowledged that). Things I've run into include when they made the CPU masks bigger, old binaries couldn't set CPU affinity (even when the old code had a mask big enough for the current CPU; we had a local patch for this, since upstream didn't seem interested in making it right). Updating to 13 at home with the approved process (install kernel, reboot, install userland, reboot (maybe), do ports/pkg update), resulted in bad network configuration because 12.x ifconfig didn't fully work with 13.0 kernel, but I believe that's been addressed; and I never hit similar issues in prod because we would install both the new kernel and new userland before rebooting, because redundant servers means you can live dangerously (if the first server fails to start, you can improve the upgrade process on the next ones). This one wasn't terrible for me, but I can imagine someone having a very negative experience and holding a grudge if they had a less accessible machine and specific network configs that made the machine unreachable after the first reboot, my machine was accessible but misbehaving and I've got easy access to the console I rolled back and later did a more cautious update. FreeBSD 11 (+/- 1) changed page inactivity policies in an unexpected way and resulted in undesired swapping for our use cases and becauae it was a slow process it wasn't obvious. That release also negatively impacted our heavy disk I/O systems in a way I didn't have time to get to the bottom of, accurate benchmarking was time consuming and user impacting and migration was in progress, so those systems were forbidden to upgrade. They didn't need the positive networking changes because of their use case, so it was acceptable.

toast0 5y ago

It depends on the specifics, but if you install the -compat packages and enable the compat kernel flags, broadly speaking old software continues to work across major versions. Anyway, just because I expect it to happen, doesn't mean it happens (and I acknowledged that). Things I've run into include when they made the CPU masks bigger, old binaries couldn't set CPU affinity (even when the old code had a mask big enough for the current CPU; we had a local patch for this, since upstream didn't seem interested in making it right). Updating to 13 at home with the approved process (install kernel, reboot, install userland, reboot (maybe), do ports/pkg update), resulted in bad network configuration because 12.x ifconfig didn't fully work with 13.0 kernel, but I believe that's been addressed; and I never hit similar issues in prod because we would install both the new kernel and new userland before rebooting, because redundant servers means you can live dangerously (if the first server fails to start, you can improve the upgrade process on the next ones). This one wasn't terrible for me, but I can imagine someone having a very negative experience and holding a grudge if they had a less accessible machine and specific network configs that made the machine unreachable after the first reboot, my machine was accessible but misbehaving and I've got easy access to the console I rolled back and later did a more cautious update. FreeBSD 11 (+/- 1) changed page inactivity policies in an unexpected way and resulted in undesired swapping for our use cases and becauae it was a slow process it wasn't obvious. That release also negatively impacted our heavy disk I/O systems in a way I didn't have time to get to the bottom of, accurate benchmarking was time consuming and user impacting and migration was in progress, so those systems were forbidden to upgrade. They didn't need the positive networking changes because of their use case, so it was acceptable.