Date: Fri, 22 May 2020 12:29:37 -0400 From: Greg Veldman <freebsd@gregv.net> To: Norman Gray <norman.gray@glasgow.ac.uk> Cc: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: Documentation and debugging for NFSv4 Message-ID: <20200522162937.GJ1068@aurora.gregv.net> In-Reply-To: <D3388CA5-84AA-48F4-8B47-8B94EFA4305A@glasgow.ac.uk> References: <D3388CA5-84AA-48F4-8B47-8B94EFA4305A@glasgow.ac.uk>
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On Fri, May 22, 2020 at 03:15:01PM +0100, Norman Gray wrote: > I'm having difficulty finding consistent documentation and debugging > tools for NFSv4. Is there some handbook-like source that I'm missing? > Or some layer of documentation for configuration or debugging that I've > failed to find? > > I've never had major problems with NFS and the associated RPC services, > but I currently find myself in a situation where some combination of v4 > exports from FreeBSD servers (11.3 and 12.1) and heterogeneous Linux > clients is behaving in a rather inconsistent way (in a context where I > can't just reboot everything in sight, which often sorts out NFS > problems...), and I'm having great difficulty diagnosing the current > service status: is server A offering what I think it is? is client B > asking for what I think it is? Normally some combination of netstat and > tcpdump would make some headway, but SunRPC is blacker magic than that. What symptoms are you seeing? Does it mount at all? If not does it give you an error message? Does it mount but is it not usable? Does NFSv3 work or is any version broken? FYI NFS problems in general usually come down to either firewall settings or MTU mismatches. If there are any firewalls between the client or server you may wish to temporarily disable them to test (or add an allow all rule). Also check that the MTU is the same for the whole path. NFSv4 introduces a couple of new things that can also be issues. The first is the v4 tree root, and the second is the concept of ID mapping to avoid the need to sync UID/GID numbers. If you can make it work with v3 but not v4, I'd start looking there. Specifically make sure you have a "V4" line in /etc/exports on the FreeBSD server, and make sure nfsuserd is running and configured with the same domain name as in /etc/idmapd.conf on the Linux side (and make sure rpc.idmapd is running on Linux). -- Greg Veldman freebsd@gregv.net
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