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BMR backup failed

Created: 15 Oct 2011 • Updated: 13 Dec 2013 | 10 comments
This issue has been solved. See solution.

Env: both NBU client and server is 7.0.1 installed on SELS 11SP1

1 BMR backup failed with the exit status  42 (network read failed).

2 I found, the NTP service is started on client, and the /proc is mounted to /var/lib/ntp/proc in ro,bind mode.

3 if I umount the /var/lib/ntp/proc, the backup can succeed. and if I mount the /proc to /var/lib/ntp/proc in ro mode, the backup can succeed.

So, my question is,  how NBU take care of the /proc filesystem when it mounted to another directory in ro,bind mode ?

Somebody please ?

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AAlmroth's picture

/proc is as far as I know managed by the procfs sub system, and is rebuilt upon boot. NTP is using a second mount of procfs to have access to its data.

I usually exclude /proc as it changes constantly, and the NBU client can be held up while re-trying backup of open files. Same goes for file system based swap files.

So in your /usr/openv/netbackup/exclude_list file you could add a /proc line.

/A

cncgz's picture

Yes.  The BMR backup with ALL_LOCAL_DRIVES can skip /proc, but can't not skip /var/lib/ntp/proc when NTP is started.

And when backup up /var/lib/ntp/proc direcotry, it lasts for 40~50 miniutes, and failed with exit status 42.

Why NBU does not skip /var/lib/ntp/proc, but does skip /proc ?

Marianne's picture

I agree that /proc should be excluded.

I am surprised though that a backup is attempted in the first place. Are you specifying the file list explicitely or backing up ALL_LOCAL_DRIVES?

If ALL_LOCAL_DRIVES, NBU should automatically exclude /proc. See this TN: http://www.symantec.com/docs/TECH52350

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
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cncgz's picture

Backuping up ALL_LOCAL_DRIVES.

Marianne's picture

/var/lib/ntp/proc is not one the default exclude items.

Create usr/openv/netbackup/exclude_list on client and add /var/lib/ntp/proc .

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

cncgz's picture

Yes. The BMR backup with ALL_LOCAL_DRIVES can't not skip /var/lib/ntp/proc when NTP is started. Because the /proc is mounted to /var/lib/ntp/proc in (ro,bind) mode.

But if I mount the /proc to /var/lib/ntp/proc in (ro) mode manually, the backup will skip the /var/lib/ntp/proc directory.

The difference of mount command output between the /proc is automatically mounted by NTP and the /proc is manually mouted to /var/lib/ntp/proc in (ro) mode by myself.

NTP: /proc on /var/lib/ntp/proc type none (ro,bind)
Myself: /proc on /var/lib/ntp/proc type proc (ro)

Marianne's picture

You have found the reason for /proc not being skipped. Look at type:

NTP: /proc on /var/lib/ntp/proc type none (ro,bind)
Myself: /proc on /var/lib/ntp/proc type proc (ro)

As per the TN that I've posted above:

NetBackup automatically excludes the following file system types on most platforms:

  • cdrom (all UNIX/Linux platforms)
  • cachefs (AIX, Solaris, SGI, UnixWare)
  • devpts (Linux)
  • mntfs (Solaris)
  • proc (UNIX/Linux platforms; does not exclude automatically for AIX, so /proc must be added manually to exclude list. If not added manually, partially successful backups may result when using the ALL_LOCAL_DRIVES directive on AIX)
  • tmpfs (Linux)
  • usbdevfs

So, if /proc is NOT mounted as type proc, you will have to add it to exclude_list.

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

cncgz's picture

Yeah, you're right, thanks.

Next setp I want to figure out the difference:

mount -o bind,ro /proc /var/lib/ntp/proc (in ntp)

mount -t proc proc /proc (in fstab)

AAlmroth's picture

The bind option allows a file system that is already mounted to be mounted at one more more additional mount points. And this is exactly what happens with NTP.

First the /proc file system is mounted as part of the boot process, and then later (in the ntpd service script) the very same file system is also mounted in /var/lib/ntp/proc as read-only so that ntpd process can access the proc structures.

So, upon a restore, the only thing that you have to make certain is that the /var/lib/ntp/proc directory exists, so that when rebooting after a BMR recovery operation, NTP can mount /proc properly.

I guess the /usr/openv/netbackup/exclude_list should contain something like /var/lib/ntp/proc/*, just to make sure that the mount point directory is restored.

/A

SOLUTION
sukam's picture

when BMR backup exclude /var/lib/ntp/proc,it can keep ntp service normal after restoring BMR?