NIS HELP Please....

[jankushka]

Re: NIS HELP Please....

good.
thanks very much.
the gnome move is a good move.
let's wait and see what happens.

cheers.

[knichel]

Re: NIS HELP Please....

Ok, well maybe I spoke too soon.  So today it hapened again.  This time the two student who's documents are hosted on the local HD (rather than mounting home via nfs) were able to continue  without issues.

To me, this seems to suggest that nfs on the server may indeed be the culprit.  So, what do you suggest at this point?  I have samba installed and working, should I switch to that vs. nfs?  Or should I install a different version of nfs from nfs-kernel-server?

Again, thank you for your time and effort.

Mike

Oh yea, when this happened, the uptime on the server was relatively low load average: 1.73, 1.15, 0.61 and top on clients and sever both showed very low cpu/ram usage.

[jankushka]

Re: NIS HELP Please....

hi.

well, success, then!
if all the nfs clients (both kde and gnome) froze and the non nfs survived,
then it seems reasonable to conclude that nfs is indeed the cause of your problems.
at last, then, it seems we were able to identify the failing bit.

we still don't know exactly "why" nfs behaves the way it behaves.
i have a feeling it could just be a capacity issue.
nfs server not able to keep up with the number of requests...
but it's guts feeling, of course.
nothing more.
and it's not that you care too much.
you want to sort this out.

i'd start by replacing kernel nfs with user space nfs as discussed in some previous post.
the switch should be straighforward and totally transparent to clients.

you could then also look at configuration/tuning issues, such as:
- have nfs use tcp rather than udp (ttbomk linux defaults to udp)
- number of nfs daemons (on both server and clients) running (e.g. nfsd)
- the soft vs hard mounts discussed some time ago

this is hopefully useful.

cheers.

[knichel]

Re: NIS HELP Please....

I will install unfs during my down time between classes (11-11:30) and still keep the 2 machines that are not using nfs the same (just in case).

Hindsight being what it is (20-20), I should have set up a secondary server for nfs only. I have many services running on my server now (www, nis, nfs, web filtering, firewall...) and if I moved nfs to a different box, if restarting that box fixed the probelm, then we would have known sooner.

I am grateful for your help. Thanks again. I will make the change today and see how it fairs...

Mike

[knichel]

Re: NIS HELP Please....

Ok, I think I am missing something. As I understood it, nfs-kernel-server and unfs are similar packages? I should uninstall nfs-kernel-server and install unfs3. When I did, all hell broke lose and I could not exportfs -ra to re-export the shares. In fact exportfs was missing.

What exactly do I need to uninstall? before installing unfs3?

Thanks.

[jankushka]

Re: NIS HELP Please....

sorry.
i assumed one package would seamlessly replace the other.
it should, though it doesn't.
it seems things are not packaged properly.

unfs3 appears to simply contain nfsd (not even dependencies)
nfs-user-user contains little more.
exportfs is in nfs-kernel-server only.

to cut a long story short: a mess!

put nfs-kernel-server back for now.

i'll try to set up some test environment.
to see how to do this stuff with kubuntu properly.

meanwhile, you could look at the tuning stuff.
i assume they apply to nfs-kernel just as well.

cheers

[jankushka]

Re: NIS HELP Please....

i managed to test nfs a little bit with kubuntu.
things are packaged for users to use nfs-kernel-server.
i've set that up for now.
however, i cannot set up an environment like yours.
so it is difficult for me to reproduce your issues.

could you please post your server's /etc/exports file and one client's /etc/fstab?
so that i can see how you have set things up and what options you have used...

cheers

[knichel]

Re: NIS HELP Please....

Thanks for your time. Here are the requested items...

SERVER Exports:

/home  192.168.6.0/255.255.255.0(async,no_subtree_check,no_root_squash,rw)

CLIENT Fstab:

192.168.6.200:/home   /home  nfs   soft  2    0

Reading about nfs mounts, I am wondering if I should be using hard mounting rather than soft?

Mike

[knichel]

Re: NIS HELP Please....

Here we go again.  Today (Oct 29) at 12:45 ish the workstations locked up.  Some observations.

1)  Users cannot launch Firefox or open there home dirs. from GUI (kde)
2)  Users CAN ctrl+alt+F1 to get to console and log in successfully and create files and folders in their home dirs at CLI.
3)  The 2 workstations that are not mounting /home via nfs are working fine with no disruption.
4)  Users can File->Save As and save currently opened document in a different location in their home dirs.

SO, It seems to me that neither NIS or NFS is causing the problem since users can log in via terminal session and since they can create files and folders via terminal session.  However, I realize that the only difference between the workstations that are not working and the 2 that are is the mounting of /home via nfs which would seem to suggest NFS.

I have tried restarting nfs-kernel-server and nis on the server as well as nis on a client.  No luck.  I cannot unmount /home on a client...

ait@ws-12:~$ sudo umount /home
umount.nfs: /home: device is busy
umount.nfs: /home: device is busy

Man this is very frustrating and confusing.  I really need to fix this as it forces me to restart the server.

Hopefully we will figure this out soon...

Oh yea, uptime shows...

~$ uptime
 13:17:55 up 3 days, 32 min, 1 user, load average: 2.12, 1.97, 1.54

[jankushka]

Re: NIS HELP Please....

you could use the lsof (list open files) command on the client's /home.
that way you should be able to see what's keeping it busy.
something like:

sudo lsof +D /home

should do it...

i am trying to get in contact with some friend of mine, that i know uses nfs with ubuntu.
they have gnome, though, not kde.
but i'll ask him to give me the details of his set up...

[knichel]

Re: NIS HELP Please....

I forgot to note that on one of my computers that use nfs, I have Gnome installed and it was in use at the time of the hang and it too was affected. So I don't think it is kde vs gnome issue.

[jankushka]

Re: NIS HELP Please....

good.
alright.
i'll come back as soon as i have the details of my friend's setup.

[knichel]

Re: NIS HELP Please....

I took 2 computers aside and tried to create a server/client using nfs-user-server and had no luck.  I do have a thought...

What if I moved /home to another server.  I cannot keep restarting my main server (also web server)since others use it besides my class.  I was thinking that if I could create a document server and keep it separate from my other services, then if I restarted it, it wouldn't matter.  My questions is this...

Since I use NIS for authentication, can I have a separate document server?  Can I mount /home from one server while authenticating against a different server?

EDIT:
Got things working with 2 different servers. One for NIS and I have moved the nfs mounting of /home to a secondary server. I cannot keep restarting my main server. This will establish one of two things.
1) IT is NFS causing the problems (because the problem continues to happen and restarting my new server solves as it has been)
2) It is NOT NFS causing the problem because the problem goes away. Or at least not nfs exclusively (maybe nfs conflicting with something else).

I have also removed my test computers putting all computers back to authentication via NIS and NFS mounting /home from my new server.

[jankushka]

Re: NIS HELP Please....

of course you can have nis and nfs on two separate systems...
on the client(s), you'll have to bind to a nis server in the /etc/yp.conf file.
and you can set where to look for what in the /etc/nsswitch.conf file...

---

my friend tells me the following:
a) his clients are all on ubuntu 6.06 lts (he says he doesn't play with versions as he wants stability)
b) his server is a redhat es running a 2.6.18 kernel
c) he exports the whole /home file system to clients with: rw,sync,fsid=0,no_root_squash
d) on the clients he has /etc/fstab set up like so

nfs-server:/    /home   nfs4  rw,bg  0 0

apart from the server running a different gnu/linux distribution (which could actually make a big difference),
the major differences are:
a) he uses nfs4 explicitly and its fsid=0 feature (notice the "peculiar" fstab entry)
b) he exports with sync (which is safer than the async you use)
c) he puts the mount op in the background (bg), if it doesn't succeed at the first try,
to prevent the boot process to stop in case the server is slow to respond

i'm not sure i'd do the same, but he says he's never seen anything like you're describing...

hth

[knichel]

Re: NIS HELP Please....

So I set up another server about 2 weeks ago and it is only serving out /home via nfs. It has not had any problems. Note that it is also using nfs-kernel-server not user-server. So, seems something might be wrong with something else on the main server ,or this is going to jinx me and it will hang tomorrow