pretz
asked on
cannot read/write/copy a file thru nfs
Hi,
I have encountered the following problem:
1. I nfs shared a directory, say, /d100 of host A, to host B with rw permission
2. Then I mounted the A:/d100 in Host B with rw permission again.
3. From Host B, I tried to access the mounted nfs dir. There is a file with the following permission set:
r-xr-lr-x owner1 group1 data.txt
4. Then as owner1 (both uid and gid are the same in Host A and Host B), I could neither cat nor copy the file data.txt, saying that permission denied. However for other files without the mandatory lock, I could always read/write them.
5. Then I move back to Host A, login as owner1, I can read/write the file data.txt locally.
Please kindly give me some idea how it is working..... to do read/write operations on mandatory locking files thru nfs... Many thanks!
I have encountered the following problem:
1. I nfs shared a directory, say, /d100 of host A, to host B with rw permission
2. Then I mounted the A:/d100 in Host B with rw permission again.
3. From Host B, I tried to access the mounted nfs dir. There is a file with the following permission set:
r-xr-lr-x owner1 group1 data.txt
4. Then as owner1 (both uid and gid are the same in Host A and Host B), I could neither cat nor copy the file data.txt, saying that permission denied. However for other files without the mandatory lock, I could always read/write them.
5. Then I move back to Host A, login as owner1, I can read/write the file data.txt locally.
Please kindly give me some idea how it is working..... to do read/write operations on mandatory locking files thru nfs... Many thanks!
ASKER
Hello,
Yes it's a read/write permission.
I can read/write files without the mandatory lock in that shared dir in the remote host, but not those with mandatory locking.
Yes it's a read/write permission.
I can read/write files without the mandatory lock in that shared dir in the remote host, but not those with mandatory locking.
ASKER
Hello,
Yes it's a read/write permission.
I can read/write files without the mandatory lock in that shared dir in the remote host, but not those with mandatory locking.
Yes it's a read/write permission.
I can read/write files without the mandatory lock in that shared dir in the remote host, but not those with mandatory locking.
ASKER
Hello,
Yes it's a read/write permission.
I can read/write files without the mandatory lock in that shared dir in the remote host, but not those with mandatory locking.
Yes it's a read/write permission.
I can read/write files without the mandatory lock in that shared dir in the remote host, but not those with mandatory locking.
From the Sun docs:
Mandatory locking works only for local files. Mandatory locking is not supported when accessing files through NFS.
Have a look at the following page for more details:
http://docs.sun.com/db/doc/806-4125/6jd7pe6at?a=view
http://docs.sun.com/db/doc/806-4750/6jdqdflt4?a=view
http://www.netsys.com/bsdi-users/2002-04/msg00059.html
So you can't do it with NFS !!!
Mandatory locking works only for local files. Mandatory locking is not supported when accessing files through NFS.
Have a look at the following page for more details:
http://docs.sun.com/db/doc/806-4125/6jd7pe6at?a=view
http://docs.sun.com/db/doc/806-4750/6jdqdflt4?a=view
http://www.netsys.com/bsdi-users/2002-04/msg00059.html
So you can't do it with NFS !!!
ASKER
thanks for the info
however when I tried to cat/cp the 'locked' file thru nfs, I was prompted 'permission denied'
but when I tried the cat/cp command on others files, they works and I can read/write on the nfs directory. (i.e., the nfs is mounted as rw successfully)
So how can I perform read/write on the locked files in nfs mounted dir? Although for doc. it said mandatory locking is not supported in nfs, the fact is I really cannot do any rw operation on it.
Many thanks
however when I tried to cat/cp the 'locked' file thru nfs, I was prompted 'permission denied'
but when I tried the cat/cp command on others files, they works and I can read/write on the nfs directory. (i.e., the nfs is mounted as rw successfully)
So how can I perform read/write on the locked files in nfs mounted dir? Although for doc. it said mandatory locking is not supported in nfs, the fact is I really cannot do any rw operation on it.
Many thanks
I think you end up have to use "tar + ssh", "rsync + ssh", or rcp / ftp (not secure to do the job).
rsync and openssh can be download from : (free):
http://sunfreeware.com/
Here's an example for copy file from box1 to box2, use tar + ssh: (tarnsfer everything under /mydir-box1 to box2, login name fred)
cd /mydir-box1
tar cf - . | ssh fred@box2" (cd /mydir-box2/backup; tar xvf - )"
once you have secure shell setup, do a
man ssh
to learn more about secure shell.
rsync and openssh can be download from : (free):
http://sunfreeware.com/
Here's an example for copy file from box1 to box2, use tar + ssh: (tarnsfer everything under /mydir-box1 to box2, login name fred)
cd /mydir-box1
tar cf - . | ssh fred@box2" (cd /mydir-box2/backup; tar xvf - )"
once you have secure shell setup, do a
man ssh
to learn more about secure shell.
silly question: what do you need mandatory locking for?
(it's very unusual in UNIX, except for special purpose like databases)
(it's very unusual in UNIX, except for special purpose like databases)
ASKER
yes, you're right. It is a file for the essbase database.
ASKER
yes, you're right. It is a file for the essbase database.
if it is locked, why do want to write it?
sounds like you try to do the wrong things ...
sounds like you try to do the wrong things ...
ASKER
Hi,
Since it was upon user's request. I did ask him why he needed to do so. He wanted to copy the file to the testing server.
Finally he tried to copy it thru ftp and it did work.
Since it was upon user's request. I did ask him why he needed to do so. He wanted to copy the file to the testing server.
Finally he tried to copy it thru ftp and it did work.
so, case close ?
ASKER
Actually I just want to know whether it is possible to do a nfs copy of this kind of files. By using ftp the file permission cannot be preserved.
If you want to preserved the file permission you can use tar to creatw a tar ball, use ftp to transfer the tar ball and then untar it.
man tar
to learn how to use tar
man tar
to learn how to use tar
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ASKER
ahoffmann,
Thank you!!!
Thank you!!!
/etc/dfs/dfstab file in you NFS server to make sure that it is shared with rw permission !