I'm trying to do a mysqldump to an external USB hard disk on Ubuntu 10.04 LTS Server

The directory on the disk has the following permissions:
drwxrwxr-x 2 root root 39 Jun 4 09:13 mysql/

Here is the command I am attempting to run (logged in as root):
mysqldump -u root -p********* database_name | gzip > /backup/mysql/database_name_`date '+%m-%d-%Y'`.sql.gz

And here is the output:
bash: /backup/mysql/database_name_06-04-2013.sql.gz: Permission denied
mysqldump: Got errno 32 on write

It also fails the same way if I take gzip out of the equation and just do:
mysqldump -u root -p********* database_name > /backup/mysql/database_name_`date '+%m-%d-%Y'`.sql

I can touch files, copy files into the directory, delete, rename, etc as root, but when I try to run this, I get permission denied. If I run the same command to a directory not on this external disk, it works fine. I don't understand what's going on here. Please help

Here's some more info:

fstab line: /dev/sdc1 /backup xfs rw 0 0
The drive is connected via USB. It's a 1TB Western Digital RE4, formatted as XFS.

Thanks guys, any ideas would be much appreciated!

The way you have worded things, I am not sure whether or not you have effectively already considered all FOUR sets of permissions that appear to be involved.

1) The permissions on the / directory.
2) The permissions on the /backup directory.
3) The permissions on the /backup/mysql directory.
4) Whether or not the specific file to which you are trying to write, might already exist, and if it does, what are that file's permissions?

HTH.

1 members found this post helpful.

run below command and after this try your stuff.

chown -R root:root /backup


sunil

1 members found this post helpful.

Even though all files and directories were already root:root, I tried this, and it resolved the problem. This was very strange.

Thank you both for your help, I greatly appreciate it!