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*SOLVED* NFS problems [message #5124] Mon, 14 August 2006 06:51 Go to next message
commy is currently offline  commy
Messages: 3
Registered: August 2006
Junior Member
Hi!

Sorry, that the topic is not more specific, but I have in fact two problems regarding NFS-space provided by a VE.

I have an OpenVZ Kernel (2.6.8-022.077) running under Gentoo with a number of VEs under Debian.

The first problem is, that I obviously can not export directories within the VE. I use the nfs-user-server (as the kernel-server seems not to work in a VE) and when I am exporting a directory based within the VE, I always get a "permission denied" error, when trying to mount that directory from a client.

The interesting part is, when mounting a directory with --bind on the HN into the VE, I am able to export that directory without any problems.

The second problem is, that I would like to use the exported directories for backup purposes. So I have made a crypted disk-image which is mounted into the VE and exported via NFS there. Then I use Apple Backup to upload the information onto the NFS-space, but Backup fails at 2 GB (I am unable to specify that in detail). There is enough diskspace available on the image. Apple Backup gives an Mac OS error -36, which corresponds to the message "I/O error (bummers)". As I have done that before on a not virtualized system, the client-side should be OK.

Does anyone have any idea about that problems?

Greetings,

Matthias

[Updated on: Tue, 26 September 2006 08:38] by Moderator

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Re: NFS problems [message #5150 is a reply to message #5124] Tue, 15 August 2006 11:31 Go to previous messageGo to next message
dev is currently offline  dev
Messages: 1693
Registered: September 2005
Location: Moscow
Senior Member

1) it would be nice to strace NFS server to get the idea why it fails on VE exported directories. Maybe NFS server thinks that it is not ext3 partition and refuses?

2) check that NFS server is compiled with large file support.
does it try to create a single file with size > 2GB or it is just a total disk space used?


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Re: NFS problems [message #5216 is a reply to message #5150] Wed, 16 August 2006 18:53 Go to previous messageGo to next message
commy is currently offline  commy
Messages: 3
Registered: August 2006
Junior Member
Hello!

dev wrote on Tue, 15 August 2006 13:31

1) it would be nice to strace NFS server to get the idea why it fails on VE exported directories. Maybe NFS server thinks that it is not ext3 partition and refuses?



Unfortunatly I did not have time to try an strace, but I will come to that.
Quote:


2) check that NFS server is compiled with large file support.
does it try to create a single file with size > 2GB or it is just a total disk space used?



Obviously the user-space NFS server at least on debian doesn't support large files, so that seems to be the problem.

So I have two options here.
1) Getting the kernel-server to run (is that possible in a VE?, It seems the nfs-kernel-server needs one or more devices, but I am unable to discover which devices I have to make available inside the VE)

2) Getting a user-space server that supports large files. I tried the debian-source but there was no corresponding configure parameter.

Matthias
Re: NFS problems [message #5249 is a reply to message #5216] Thu, 17 August 2006 06:56 Go to previous messageGo to next message
dev is currently offline  dev
Messages: 1693
Registered: September 2005
Location: Moscow
Senior Member

1) theoretically it's not very very hard to get it working in VE, but this requires kernel changes and time to investigate :/

2) can you provide the link to the sources of NFS user space server?
maybe it is faster to find the way to fix it....
I will definetely ask Vasiliy to check this next week and find a possible way to do it.



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Re: NFS problems [message #5250 is a reply to message #5249] Thu, 17 August 2006 07:16 Go to previous messageGo to next message
commy is currently offline  commy
Messages: 3
Registered: August 2006
Junior Member
dev wrote on Thu, 17 August 2006 08:56

2) can you provide the link to the sources of NFS user space server?
maybe it is faster to find the way to fix it....
I will definetely ask Vasiliy to check this next week and find a possible way to do it.



Sure: http://ftp.debian.org/debian/pool/main/n/nfs-user-server/nfs -user-server_2.2beta47.orig.tar.gz

Matthias
Re: NFS problems [message #5555 is a reply to message #5124] Wed, 23 August 2006 13:15 Go to previous messageGo to next message
Vasily Tarasov is currently offline  Vasily Tarasov
Messages: 1345
Registered: January 2006
Senior Member
Hello, Commy,
I've done some experiments with user-space nfsd.

Quote:

The first problem is, that I obviously can not export directories within the VE. I use the nfs-user-server (as the kernel-server seems not to work in a VE) and when I am exporting a directory based within the VE, I always get a "permission denied" error, when trying to mount that directory from a client.


The problem is that rpc.mountd, rpc.nfsd check for mounted nfs partion on server using major number of device. For simfs major also (like nfs) equals zero - so while checking this they think that nfs is mounted already and don't grant access.
The workaround here is to run rpc.mountd and rpc.nfsd with -r option:
# rpc.mountd -r
# rpc.nfsd -r

Quote:

... but Backup fails at 2 GB ...

user-nfsd implements NFSv2 and this standart version limits size of files to 2 GB! =)
So just use unfs3 (http://unfs3.sourceforge.net/) user-space server, that implements NFSv3.

Good luck! =)
Re: NFS problems [SOLVED:unfs3] [message #6794 is a reply to message #5555] Fri, 22 September 2006 14:43 Go to previous message
mike is currently offline  mike
Messages: 7
Registered: September 2006
Location: Kiev, Ukraine
Junior Member

ACK, unfs3 Just Works (TM). Had to figure out that LTSP did put the directory it was lazy to create into /etc/exports (and unfsd refused to export anything while complaining loudly in a log); after fixing that up, things went bright. Well, there was another patch needed to fix LTSP's terminal image startx script, but that's their lapse at sanitizing input...

Thanks for the tip.


--
Michael Shigorin
OSDN.Org.UA / ALT Linux Team
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