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As a FreeBSD developer, perhaps you know what tunables are being talked about for specific use cases? Unrelated, I find it surprising that any major operating

As a FreeBSD developer, perhaps you know what tunables are being talked about for specific use cases? Unrelated, I find it surprising that any major operating system these days need rebooting because "every third day or so otherwise the performance degraded a lot". Or maybe they just didn't increase the sysctl var kern.full_performance_days high enough ;)

alacombe 7y ago
I've been running Fedora for ~10 years (switching away from {Net,Free}BSD, I was fed-up to re-invent the wheel and the general poor design of the OS / high inertia of the community), and never rebooted once for "performance reason". My average uptime is in the couple of month, always for hardware / maintenance reason. Even my Windows 10 machines is never rebooted because of performance issue. I don't think I've had much system failure / panics either.
toast0 7y ago
I wouldn't worry too much about that claim. It seems like a poorly remembered claim about about a very old version. I'm sure somebody has the battlescars and could tell you what it was exactly. My guesses would be a memory leak somewhere, some yucky disk controller bug I didn't run into, or possibly the TCP LAST_ACK state accumulation https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=25986 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=25986 This has since been fixed, although it did take an annoyingly long time; but before it was fixed, you could address it by tuning socket buffers to be smaller --- it seemed to be less likely for clients to disappear with unacked data, but also, when they did, it wasn't as noticeable. Most things are tuned pretty well by autotuning these days though. If your work is more I/O limited than CPU limited though, tuning is more likely to be useful.
loeg 7y ago
> As a FreeBSD developer, perhaps you know what tunables are being talked about for specific use cases? There are tons of knobs and I don't set or know anything about any of them in particular, sorry. > Unrelated, I find it surprising that any major operating system these days need rebooting because "every third day or so otherwise the performance degraded a lot". Me too. I assumed the author was talking about some (awful) historic bug rather than an ongoing issue they're having. Kinda sounds like a kernel memory leak, but it could be anything.

alacombe 7y ago

I've been running Fedora for ~10 years (switching away from {Net,Free}BSD, I was fed-up to re-invent the wheel and the general poor design of the OS / high inertia of the community), and never rebooted once for "performance reason". My average uptime is in the couple of month, always for hardware / maintenance reason. Even my Windows 10 machines is never rebooted because of performance issue. I don't think I've had much system failure / panics either.

toast0 7y ago

I wouldn't worry too much about that claim. It seems like a poorly remembered claim about about a very old version. I'm sure somebody has the battlescars and could tell you what it was exactly. My guesses would be a memory leak somewhere, some yucky disk controller bug I didn't run into, or possibly the TCP LAST_ACK state accumulation https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=25986 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=25986 This has since been fixed, although it did take an annoyingly long time; but before it was fixed, you could address it by tuning socket buffers to be smaller --- it seemed to be less likely for clients to disappear with unacked data, but also, when they did, it wasn't as noticeable. Most things are tuned pretty well by autotuning these days though. If your work is more I/O limited than CPU limited though, tuning is more likely to be useful.

loeg 7y ago

> As a FreeBSD developer, perhaps you know what tunables are being talked about for specific use cases? There are tons of knobs and I don't set or know anything about any of them in particular, sorry. > Unrelated, I find it surprising that any major operating system these days need rebooting because "every third day or so otherwise the performance degraded a lot". Me too. I assumed the author was talking about some (awful) historic bug rather than an ongoing issue they're having. Kinda sounds like a kernel memory leak, but it could be anything.