On Thu, 2016-11-10 at 10:54 +1100, NeilBrown wrote: > On Wed, Nov 09 2016, Jeff Layton wrote: > > > On Wed, 2016-11-09 at 14:46 +1100, NeilBrown wrote: > > > Hi, > > > I notice that nfsdcltrack has a "--storagedir" option. > > > I wonder how this can be used, given the nfsdcltrack is only(?) called > > > from the kernel and there is no(?) mechanism to pass extra options. > > > > > > In a clustered-server context it would make sense(?) to share the > > > database between cluster nodes and it is easiest to do this if the > > > file in a separate filesystem (mounted as part of fail-over) rather > > > than in /var. > > > This can(?) be achieved using a symlink, but rpm likes to remove > > > symlinks to non-existent locations. > > > > > > With NFSv3 the equivalent is the state files maintained by statd, and > > > these can be relocated by passing the -P option to rpc.statd. > > > How does one do a similar thing for NFSv4??? > > > > > > > > > > Ahh, I added that option mostly for when I was testing it. I did a lot > > of the earlier testing running it by hand, and --storagedir let me use a > > different directory for the db. I did have a vague idea that we might > > use it in the situation you describe, but I never wired that up as I > > didn't have a real need for it. > > > > We could add a new module parm that would set that option when the > > kernel does its callout, or allow passing the storagedir by environment > > variable. > > > > What would make the most sense from a usability standpoint? > > Maybe a config file in /etc/ which nfsdcltrack reads on start-up? > Though in some ways I'd rather that instead of running a program, the > kernel sent a message to user-space. Possibly a u-event? > Then existing configuration mechanisms could be used to choose a program > and a context for it to run in. > I wonder if u-events handle namespaces at all. > > This came up because a customer was symlinking all of /var/lib/nfs to > shared storage (and lost their symlink thanks to rpm). That isn't a > solution that I really like, and it led me to reflect on other things in > /var/lib/nfs. > > etab - holds a normalized copy of /etc/exports, plus ad hoc changes. > It would like in /run/nfs if we built this today > export-lock - lockfile to protect changes to above. Would also be > in /run if we built it today. (I wonder why that doesn't > use .etab.lock, which is already used for locking) > state, sm, sm.bak - statd state files. These belong in /var/lib/nfs > but are easily relocated with args to rpc.statd and sm-notify. > v4recovery - the NFSv4 version of above > xtab - this hasn't been needed since we gained /proc/fs/nfs/exports > It is just a record of what should be in the kernel > We should remove this. I'll make a patch. > rmtab - this hasn't been needed since the "new cache" and the > up-call mechanism were created. It might be still used > to respond to "showmount" commands, but that was never reliable. > If we keep it, it should probably move to /run. > But what do people think if finally discarding the old > (non-new_cache) code and using that as an excuse to increment > the major version number of nfs-utils? > > rpc_pipefs - mountpoint of NFS upcall filesystem. This was another > source of problems when /var/lib/nfs is a symlink elsewhere. > It isn't nice to mount this filesystem on that shared storage. > While programs that access this can be told to use an alternate > directory, it is hard to tell systemd's unit files to mount > it somewhere special (previously an init script would just > mount it wherever the config file said) > I note that Debian mounts this at /run/rpc_pipefs. > That seems like a really good idea. What do people think of > making this the "official" mount point? > > If we moved some things to /run and removed others, it would just leave > state,sm,sm.bak and v4recovery in /var/lib/nfs. That is all the same > type of data, which is nice. > > So there are lots of things we could do, but at a minimum - > /etc/nfsdcltrack.conf ?? > > Thanks, > NeilBrown No objection here, especially if we make it so that we have existing behavior when there is no config file. nfs-utils even has some config file parsing routines now in support/nfs that should be sufficient. -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
