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freeze on mount nfs home directory

Posted on 2002-04-18
Medium Priority
Last Modified: 2013-12-16
I have three computers, one server, and computers A and B
   RH 7.2 custom 2.4.17 kernel
   RH 7.2 default 2.4.7-10 kernel

both are configured with NIS and NFS to the server.  Computer A logs in successfully and starts gnome with no problem.  Computer B logs part way in to gnome, and freezes.  All activities referencing the home dir also freeze.  If logging in on console on B, can see files, but when trying to access one, teh same freeze.  This does not happen on computer A.

On a similar note, gdm would not allow logins by the users that were over NIS, while xdm does.  why?

Can anyone help?
Question by:blackc
LVL 40

Expert Comment

ID: 6953559
RH 7.2, "out of the box", participates just fine in an NIS/NFS environment. It works a tad better with the RedHat erratas installed, but you shouldn't be having any problems like the above. It's not completely clear from the question, but it sounds like system B has basic network connectivity (i.e., yopu can ping system A and the server from B and vice versa).

This sounds like there may be a networking problem with box B. The first thing I'd look at would be to see if there's a link speed/mode mis-match occuring on the system. That can happen if you have a 10/100 NIC card and are connecting to a 10/100 hub or switch. A simple test that can reveal a link problem is to do an FTP transfer of a 3-5Mb file from B to the server. You want to do both a "get" and a "put" and note the transfer rate in each direction. On a 100Mbps network connection you should be getting something in the 6-8Mb/sec range. If there's a link speed/mode mis-match the transfer rates will be in the tens of Kb/sec range or below.

Fixing a link negotiation problem usually involves forcing one or both ends of the link to a specif speed and mode. There are tools at http://www.scyld.com/diag/ for a number of NIC cards that can be used to set the NIC. What can be done at a switch, if anything, depends on what kind of switch you have. Hubs and simple unmanaged switches can't have their side set at all.

Other things to check are to see if you can do a ypcat of each of the NIS maps and to see if you can manually mount and normally access files in a home dir exported from the server.

Assisted Solution

tallat earned 400 total points
ID: 6953672
well with effect of your question i think there is some problem with your network card first of all check your network card and try to reinstall the network card or update the drivers because u r accessing the things through network that first of all clear the things in your mind that there is no prob in operating system so check your networking card and his performance.

Author Comment

ID: 6956884
Well, i tried to do the ftp test, but much to my dismay, discovered that it can't ftp to anything.  It won't even connect to the other box (B).  Telnet has the same behavior, yet ssh works fine.  I have NIS configured, and it is working just fine, but the NFS file system still hangs at every access.  the server is running a recompiled redhat 7.2 2.4.7-10, would the version differences cause problems?  the machine also can't telnet to any computer outside the network, as well as inside.  computer A works fine, accessing nfs partitions and all, could it be that i have a bad network card that allows ssh, nis, and ping to work fine, yet refuses to let telnet and ftp work, or is that going to be the operating system, and if it is, is it because of the kernel?  should i upgrade it to 2.4.17?
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LVL 40

Expert Comment

ID: 6956993
I'm not sure that I understand completely how you did the test. I had wanted you to login on box B as root and try the FTP from there. Of course that would require that you have FTP enabled on the server and that you knew that it worked by doing an FTP transfer while logged in to A (which doesn't have any problems).

I don't think that you could have a NIC problem that would allow ssh but not telnet or FTP. That sort of behaviour sounds more like a firewall ruleset or something do to with tcpwrappers (as in ssh is allowed but telnet and FTP aren't). If it were to be a firewall or tcpwrappers problem that might explain the NFS problem. Check to see that system B and the server don't have any firewalls active and that hosts.allow and hosts.deny are empty of everything except comments.

I know for certain that the as-installed kernel on 7.2 will do NFS and since system A (running 2.4.17) can use the NFS exports I really don't think that the kernel on the server is the problem. If neither A or B could access NFS exports from the server I'd be tempted to blame the re-compiled kernel, but not in this case.

It still looks like the problem is one of the configuration of system B or a problem with the NIC and its speed/mode. Do compare the output of "ifconfig -a" on A & B and make sure that the correct network settings are correct (IP, netmask and broadcast). Also check to make sure that the same default gateway is set (look at netstat -rn) and that the DNS is configured the same (/etc/resolv.com).

Author Comment

ID: 6957006
they are all the same, all those things that you told me to look at.  Hosts.* are empty, the only firewall in place is on the server, and it allows traffic in based on the interface only, and both computers are on the same interface.  ifconfig returns the same (except for ip obviously), netmask and broadcast are both the same, default gateway and the rest of the routing table is correct, and the dns is identical.  As i just discovered, the NIS also won't automatically update, it times out while trying with ypxfr, but ypinit -s _____ works.
LVL 40

Expert Comment

ID: 6957947
I didn't expect there to be any problems with the network configuration of the machines, but it doesn't hurt to double check. An inconsitant netmask cause some really odd problems.

Everything still points to some basic networking problem. And, as I've mentioned, mis-negotiation of link speed/mode is a prime candidate. You really need to do the FTP test between system A and the server, system B and the server, and system A to system B. This might require installing an FTP server one or more of the systems. FTP is the best check for this because nothing else will stress a network connection like an FTP transfer.

Author Comment

ID: 6958124
all have ftp servers and clients installed, i have previously used them on the systems, and currently use it between A and the server, and the server and A.  B simply won't connect with ftp or telnet, so i don't know how i can do the test.
LVL 40

Accepted Solution

jlevie earned 400 total points
ID: 6958185
Okay... How about letting me see what the firewall rules are on the server and what 'ifconfig -a' on system B looks like?

When you do an FTP transfer between the server and A what are the rates in each direction?

Expert Comment

ID: 9077027
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Expert Comment

ID: 9220336
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