Symptoms

During the attempt to download a backup from backup repository, a default 'not found' error is being displayed in browser for the alike URL:

https://1.2.3.4:8443/plesk/client@332/domain@445/backup/local-repository/item@0x27eadef51be706357c12fc91f4a5ed82/download/?_randomId=774236

'/var/log/sw-cp-server/error_log' contains the following errors:

2013/12/26 13:31:48 [error] 1783#0: *181486 open() "/usr/local/psa/admin/htdocs/var/tmpfs/dumpOgN2qd.tar" failed (2: No such file or directory), client: 4.3.2.1, server: , request: "POST /plesk/client@332/domain@445/backup/local-repository/item@0x27eadef51be706357c12fc91f4a5ed82/download/?_randomId=774236 HTTP/1.1", upstream: "fastcgi://unix:/var/run/sw-engine.sock", host: "1.2.3.4:8443", referrer: "https://1.2.3.4:8443/plesk/client@332/domain@445/backup/local-repository/"

Where 1.2.3.4 is your server IP and 4.3.2.1 is the IP of a machine from which you try to connect.

Cause

The situation above could be caused by a symbolic link in place of the Plesk dump directory:

[root@ns358953 ~]# grep DUMP_TMP_D /etc/psa/psa.conf
DUMP_TMP_D /tmp

[root@ns358953 ~]# ll -d /tmp
lrwxrwxrwx 1 root root 11 Dec 26 14:44 /tmp -> /var/tmpfs/

PHP works incorrectly in case if the path is a symlink.

Resolution

Remove the link and create a bindmount instead:

[root@ns358953 ~]# unlink /tmp
[root@ns358953 ~]# mkdir /tmp
[root@ns358953 ~]# chmod 777 /tmp
[root@ns358953 ~]# mount -o bind  /var/tmpfs/ /tmp/

And add the following line to '/etc/fstab' :

/var/tmpfs              /tmp                 none    bind    0 0