Networker client to support btrfs filesystem

[swadm]

in the Networker 8.2 Admin Guide we read:

   Linux Journaled file system support

   Backup and recovery operations are supported on the following Linux

   journaled file systems:

   - ext3

   - reiserfs

   - jfs

   - xfs

No statement about support of BTRFS.

I fear that the networker client cannot handle btrfs filesystem.

SuSE Enterprise Linux (SLES) 12 comes with the installation default of BTRFS for the OS, and docker can profit a lot from BTRFS based installations.

Networker client should really provide BTRFS support very soon!

You are welcome to voice affirmation

Regards, Tom

[bingo.1]

You are right - there is no such statement. Instead, the Compatibility Guide states that "All POSIX compliant file systems are supported."

But I have not found any statement whether BTRFS fulfills this requirement.

[swadm]

Apparently, Networker actually does backups of mounted BTRFS file systems, but I would like to see BTRFS explicitely mentioned where ext3, xfs etc are mentioned, and I cannot say if the current backups are sufficient:

• I see that some pathes visible in subdirs of /var/lib/docker (with docker setup to use BTRFS) are not backed up, and cannot explain why
• With no explicit support from EMC, I doubt that the backup and restore of extended file attributes or poxix ACLs is being tested by EMC
• Furthermore, Networker client would have to implement some deeper understanding of  BTRFS internals, as it would need to avoid the backup of each mounted snapshot pointing to identical BTRFS leaves. The article about HP data protector has details about this issue

We will be submitting an enhancement request to implement full BTRFS support in Legato Networker ASAP, and anybody that also needs it is welcome to submit such an enhancement request, too.

Kind regards, Tom

[swadm]

Just heard that BTRFS support is being worked on for upcoming feature release 9.1.

As version 9 is so much different from version 8.x, I would still appreciate BTRFS support in V8.2.x for example.

Kind regards, Tom

[swadm]

As Networker 9.1 has been released, I wonder whether btrfs support has somehow made it into the new features. Could not find anything about it. Does somebody know more?

[wlee4]

According to the 9.1 online software compatibility guide:

BTRFS: For Sub-volume Backups use save -x option.

BTRFS: No support for BBB/PP/NSM.

[swadm]

Wallace, thanks!

Do you know if there is a chance that btfrs support might be backported to a Networker 8 version.

Moving to 9 is quite a challange ...

[wlee4]

The compatibility guide also shows the same information for NetWorker 8.2.x on Linux clients:

BTRFS: For Sub-volume Backups use save -x option.

BTRFS: No support for BBB/PP/NSM.

You can find all 8.2.x install kits at:

ftp://ftp.legato.com/pub/NetWorker/Cumulative_Hotfixes/8.2

[swadm]

Wallace, that's good news, and very interesting! I still have some questions needing clarifiction:

From the release notes of Networker 8.2.4:

Linux BTRFS file system support

NetWorker 8.2.4 supports backups of B-tree file systems (BTRFS).

When a server-initiated backup starts, only BTRFS sub-volumes that are configured in

the /etc/vfstab file are backed up. When NetWorker encounters a subdirectory

that has a sub-volume ID that differs from the parent sub-volume ID, NetWorker does

not back up the contents of the subdirectory, unless you specify the save -x

command in the Backup command field in the properties of the Client resource.

When you specify a BTRFS volume or sub-volume save set during a manual backup,

NetWorker performs a recursive back up of the directory tree that you specified with

the save command. When NetWorker encounters a subdirectory that has a subvolume

ID that differs from the parent sub-volume ID, NetWorker does not back up

the contents of the subdirectory, unless you specify the -x option with the save

command.

BTRFS is not supported with the following features:

- Block based backup

- NetWorker snapshot management

I assume that this new feature will also require that client and server be on at lease 8.2.4?

The concept of /etc/vfstab is not known in SLES 12, as far as I know. How will the client behave on platforms without /etc/vfstab support?

As I see that my current 8.2.3 client does (dumb?) backups of btrfs subvolumes (like var/log in SLES 12), to my understanding, moving to a current 8.2.4 client bears the risk that there will be less or no backup of btrfs subvolumes in the absense of a proper configuration (or /etc/vfstab support on platforms like SLES): quite dangerous, agree?

Kind regards, Thomas

[swadm]

I believe that /etc/vfstab is SVR4 specific, and is rarely used outside of Solaris. Why did EMC choose to implement the btrfs backup configuration in such a highly non portable location?