What is '--Extra header --' that nbu tar -tvf X.img shows?

[Charley90]

Dear all,

Any one can explain what is the '--Extra header --'    (below) ? 

Can I manually tar a file with 'Extra header' info inside ?

Thanks.

[root@localhost test_cl]#  /usr/openv/netbackup/bin/tar -tvf localhost_1495795606_C1_F1.1495795606.img 
Blocksize = 64 records
Er-xr-xr-x root/root 103 May 26 06:47 2017 .AtTrIbUtEs.0
--Extra header --
dr-xr-xr-x root/root 0 May 25 16:36 2017 /
Erwxr-xr-x root/root 102 May 26 06:47 2017 .AtTrIbUtEs.1
--Extra header --
Erwxr-xr-x root/root 512 May 26 06:47 2017 .LoNg_VaLuEs.0
drwxr-xr-x root/root 0 May 25 11:13 2017 /mnt/
Erwxr-xr-x root/root 106 May 26 06:47 2017 .AtTrIbUtEs.2
--Extra header --
Erwxr-xr-x root/root 512 May 26 06:47 2017 .LoNg_VaLuEs.1
drwxr-xr-x root/root 0 May 26 06:46 2017 /mnt/dir02_null/
Erw-r--r-- root/root 106 May 26 06:47 2017 .AtTrIbUtEs.3
--Extra header --
Erw-r--r-- root/root 512 May 26 06:47 2017 .LoNg_VaLuEs.2
-rw-r--r-- root/root 19 May 26 06:46 2017 /mnt/dir02_null/abc
Erw-r--r-- root/root 106 May 26 06:47 2017 .AtTrIbUtEs.4
--Extra header --
Erw-r--r-- root/root 512 May 26 06:47 2017 .LoNg_VaLuEs.3
-rw-r--r-- root/root 80752640 May 26 06:46 2017 /mnt/dir02_null/NBU_mount01.tar
Erwxr-xr-x root/root 106 May 26 06:47 2017 .AtTrIbUtEs.5
--Extra header --
Erwxr-xr-x root/root 512 May 26 06:47 2017 .LoNg_VaLuEs.4
drwxr-xr-x root/root 0 May 26 06:46 2017 /mnt/dir02_null/dir2/
Erwxr-xr-x root/root 106 May 26 06:47 2017 .AtTrIbUtEs.6
--Extra header --
Erwxr-xr-x root/root 512 May 26 06:47 2017 .LoNg_VaLuEs.5
drwxr-xr-x root/root 0 May 26 06:46 2017 /mnt/dir02_null/dir/
Erw-r--r-- root/root 106 May 26 06:47 2017 .AtTrIbUtEs.7
--Extra header --
Erw-r--r-- root/root 512 May 26 06:47 2017 .LoNg_VaLuEs.6
-rw-r--r-- root/root 80752640 May 26 06:46 2017 /mnt/dir02_null/dir/NBU_mount01.ta

[Marianne]

This post is already one month old...

The only person I know who might know this is @mph999.

Martin? 

[mph999]

 .../netbackup/bin/tar is a modified version of GNU tar - and as far as I know, it's just part of the GNU tar format, requitred to make tar do it's thing ...  Exactly what they contain /do is beyond my knowledge I'm afraid.

[Mike_Gavrilov]

/* The GNU extra header contains some information GNU tar needs, but not
   foreseen in POSIX header format.  It is only used after a POSIX header
   (and never with old GNU headers), and immediately follows this POSIX
   header, when typeflag is a letter rather than a digit, so signaling a GNU
   extension.  */

What do you mean under "Can I manually tar a file with 'Extra header' info inside ?" Extract?  Try to use -xvpf keys to extract.

P.S. In newer versions NBU uses nbtar.