man nfs

Posted Mar 6, 2020 19:45 UTC (Fri) by flussence (guest, #85566)
In reply to: man nfs by willy
Parent article: Quote of the week

I've had columns of "D" appear in top for reasons I've never really figured out. Some of it's autofs struggling to mount it, but sometimes it freezes up on already-mounted filesystems. I've had hung mounts that I'm pretty certain were caused by jumbo ethernet frames too - any mtu above about 4000 seems flaky.

To be clear and just so I'm not constantly complaining: the other 99% of the time it works it's fantastic. I'm grateful for all the work that went into this. Even if these few sore spots don't get fixed, I feel less frustrated just having the acknowledgement that it's like that sometimes and I'm not imagining it.

man nfs

Posted Mar 6, 2020 19:54 UTC (Fri) by willy (subscriber, #9762) [Link]

Next time you have a task stuck in D state, it'd be great if you could send /proc/$pid/stack to linux-fsdevel, because I strongly feel that when a user hits ^C, the task should die.

I didn't remove any places which would have been interruptible before, so the only difference is that now non-fatal signals won't interrupt a read.

man nfs

Posted Mar 16, 2020 22:29 UTC (Mon) by nix (subscriber, #2304) [Link] (2 responses)

I've had hung mounts that I'm pretty certain were caused by jumbo ethernet frames too - any mtu above about 4000 seems flaky.

It must be more than that: I've never had hung mounts on the link to the NFS server here, which has an MTU of 6128 (because of limits on one of the network cards in question), not on NFSv3 nor NFSv4.0 nor NFSv4.1. And if I had hung mounts, I'd know it: my $HOME is on NFS...

man nfs

Posted Mar 19, 2020 8:33 UTC (Thu) by flussence (guest, #85566) [Link] (1 responses)

Personally, I'm inclined to blame these el cheapo onboard Realtek NICs I keep winding up with… if this was a kernelspace bug I'd hardly be the first to discover it.

man nfs

Posted Mar 19, 2020 22:09 UTC (Thu) by nix (subscriber, #2304) [Link]

It's not even all of those: the machine I'm typing this on has NFSv4 $HOME and a Realtek 8168 and has been more or less flawless. (Not that I'll be using that for much longer: I'm going 10GbE, with an X540-T1, instead. Yes, 10GbE to the desktop is now practical without needing to win the lottery first :) )