VNX: Filesystem loop detected when running "find" on Control Station
Zhrnutie: VNX: The file system loop detected when running "find" on the Control Station.
Symptómy
User is running the find command on the control station when looking for a file in a file system mounted on the data mover.
User receives a "Filesystem loop detected" error when running the linux find command as root user from the root "/" directory of the control station to try to search for a file.
"find: Filesystem loop detected; `/nasmcd/quota/slot_7/fs03group61/mail/61'" has the same device number and inode as a directory which is three levels higher in the file system hierarchy.
The find command stops responding when running it on the control station.
Príčina
When using the find command on a VNX or Celerra Control Station from as root user from the root "/" directory, find searches the entire system for the keyword specified, this includes all customer file systems mounted on the data movers (ex: "/nas/quota/slot_2/fs_name/"). Because the control station directory structure is a different physical file system than the customer file systems mounted on the data mover. Each of these two file systems may share the same inode numbers.
When the find command detects the same inode number from a previous directory that it has already searched in, the error displays and the command may stop responding.
In this scenario, because the control station directory structure and customer directory structure are on separate physical file systems, the error can be ignored.
Using the "ls -ial" command we can check the inode #'s between the two different file systems and confirm that the inode numbers are duplicate.
In the below example, the inode # is displayed in the left column of the "ls -ial" output.
Example:
[root@VNX001 /]# find / -name rpt_file /nasmcd/quota/slot_7/fs03install/.etc/rpt_file /nasmcd/quota/slot_7/fs03db99/.etc/rpt_file /nasmcd/quota/slot_7/fs03sub/.etc/rpt_file /nasmcd/quota/slot_7/fs03audit/.etc/rpt_file /nasmcd/quota/slot_7/fs03group99/.etc/rpt_file <<<<<Filesystem loop detected here
"find: Filesystem loop detected; `/nasmcd/quota/slot_7/fs03group61/dir/99'" has the same device number and inode as a directory which is three levels higher in the file system hierarchy.
Notice that comparing the directory structures 3 levels up, the two files named "." and "99" share the same inode #.
[root@VNX001 slot_7]# ls -ial /nasmcd/quota/slot_7/ total 552 2 drwxr-xr-x 37 root root 2048 Aug 10 2015 . <<<inode # is 2 5695 drwxr-xr-x 17 root root 0 Jul 15 01:00 .. 4 dr-xr-xr-x 13 root bin 2048 Apr 16 2015 .etc 18446744071562067968 drwxr-xr-x 6 root root 1024 Sep 8 2013 .etc_common 3 drwxr-xr-x 2 root root 8192 Sep 8 2013 lost+found ....(output omitted).... [root@VNX001 slot_7]# [root@VNX001 slot_7]# ls -ial /nasmcd/quota/slot_7/fs03group99/mail/ <<<Note different directory total 2448 75 drwxrwx--- 102 103 101 4096 Oct 10 2013 . 95 drwxrwx--- 7 103 101 1024 Sep 12 2013 .. ....(output ommited)... 2 drwxrwx--- 301 103 101 25600 Jul 26 20:24 99 <<<inode # is 2 ....(output ommited)... [root@VNX001 slot_7]#
Riešenie
This is not a break/fix issue. The error reported is the expected behavior of the command. Control Station has access to the mounted data mover file systems under /nas/quota/, so the find command may find an inode loop as their are different file systems mounted.
While running the find command is not disruptive to the production environment, it is not recommended to run the command root in the "/" or "/nas" directory level on the Control Station.