NFS lockups, default read/write size too big?
 

I've had a persistent issue for a while where sometimes large copies or writes to a NFSv4 server would hang the client machine access to that disk (incl sync and reboot) and spam the network with retries. The logs on the server get filled with things like this:

Mount options are hard,nfsv4 and it never seems to give up and you have to power cycle or reset the client to recover.

Both client and server are using the same slackware64-current and although I use kernel.org kernels it's been a problem since I set it up so it's spanned many versions. It's currently nfs-utils-2.5.4 the server kernel is configured with only NFS version 4 support (no 4.x options).

I modified /etc/nfsmount.conf to set R|W|Bsize to 64K and it seems to have fixed it. I'm happy with that solution but I'm wondering if it either points to some package config issue that might be of interest to others or if it's just something local that doesn't matter (network, kernel config, etc).

How long ago since you set it up? People have mentioned NFS issues in the kernel thread going back a bit over a month, the main issue most were having was solved a few versions later. But personally I continued to have serious NFS performance issues until 5.13.4 was released 2 days ago.

I have no idea if its related to your issues though. Seems as of late NFS issues and patches going through the kernel have been plentiful.

NFS patches mailing list

https://lore.kernel.org/linux-nfs/

Yeah it seems unusually busy of late, then again a lot of maintenance stuff seems unusually busy and with too many reverts for my liking.

I think I set it up about October last year so perhaps starting around 5.8.x going off filestamps in /boot/efi and i've tried most of the 5.x series since. I usually do big file operations on the server so I don't hit it very often so I can't say if it's just some kernels or all of those. I can't remember when i first saw it but do remember it first happened after a kernel upgrade -- but that could just be a coincidence due to the way I use it.

Apart from the hangs from the xfer size it's been ok enough but I don't have much in the way of expectations.