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… cannot read media header, may not be NetBackup media or is corrupted (172)

Hello ALL,

Netbackup 7.1

Redhat 2.6

 

We suffering with the following issue:

When we are trying to restore from tape , stopping with this error:

annot read media header, may not be NetBackup media or is corrupted (172)

We've tried with this links:

https://www.veritas.com/support/en_US/article.TECH18639

and then with this one

https://vox.veritas.com/t5/Netting-Out-NetBackup/How-to-use-tar-to-restore-data-off-of-a-tape/ba-p/7...

(On this link we couldn't get  block size :

bpmedialist -mcontents -m E978L5
cannot read media header, may not be NetBackup media or is corrupted)

 

Do you have any suggestions ?

BR,

Turgun

 

Tags (2)
18 Replies

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

  • Has any form of media server encryption been used ?
  • Have you tried the same operation on two diffrent tape drives ?
  • Are you sure the tape drive can read the media, e.g a LTO5 cartrige on a LTO4 tape drive ?

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

  • Has any form of media server encryption been used ?
  • ==> No, No encryption
  • Have you tried the same operation on two diffrent tape drives ?
  • ==>  Yes, we've tried on 2nd, 3rd drive. But no success. 
  • Are you sure the tape drive can read the media, e.g a LTO5 cartrige on a LTO4 tape drive
  • ==> Yes, Tape drives are functioning properly. Because another backups are working. For test, we've restored some data from another cartridge.

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

I assume that you are trying to restore from a tape drive of the same vendor. If not and you know the drive that backup use, try to use it for the restore.

check if you can read the tape and if the tape header is ok

https://www.veritas.com/support/en_US/article.TECH73812

https://www.veritas.com/support/en_US/article.TECH8781

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

No, I couldn't read the media header :

# /usr/openv/volmgr/bin/tpreq -m  E978L5 -d dlt -p SN_ArchiveSMSC2 -f /tmp/292
# mt -f /tmp/292 rewind
# dd if=/tmp/292 bs=1024 | od -cx
0000000  \0  \0  \0 002   g   e   o   s   m   s   c   2   _   1   4   4
           0000    0200    6567    736f    736d    3263    315f    3434
0000020   9   1   2   0   7   2   7  \0  \0  \0  \0  \0  \0  \0  \0  \0
           3139    3032    3237    0037    0000    0000    0000    0000
0000040  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
           0000    0000    0000    0000    0000    0000    0000    0000
*
0000200  \0  \0  \0  \0   V   _ 323 327 177 377 377 377  \0  \0  \0  \t
           0000    0000    5f56    d7d3    ff7f    ffff    0000    0900
0000220  \0  \0  \0 001  \0  \0 005 240  \0 004  \0  \0  \0  \0  \0  \0
           0000    0100    0000    a005    0400    0000    0000    0000
0000240   E   9   7   8   L   5  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
           3945    3837    354c    0000    0000    0000    0000    0000
0000260  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0 001  \0 003  \0  \0
           0000    0000    0000    0000    0000    0100    0300    0000
0000300  \0  \0  \0  \0  \0  \0  \0  \0   T   h   I   s       I   s    
           0000    0000    0000    0000    6854    7349    4920    2073
0000320   A       B   P       B   a   C   k   U   p       H   e   A   d
           2041    5042    4220    4361    556b    2070    6548    6441
0000340   E   r  \0   S   N   _   A   r   c   h   i   v   e   _   S   M
           7245    5300    5f4e    7241    6863    7669    5f65    4d53
0000360   S   C   2  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
           4353    0032    0000    0000    0000    0000    0000    0000
0000400  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
           0000    0000    0000    0000    0000    0000    0000    0000
*
0000540  \0  \0  \0  \0   O   p   e   n   m   i   n   d   _   A   r   c
           0000    0000    704f    6e65    696d    646e    415f    6372
0000560   h  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
           0068    0000    0000    0000    0000    0000    0000    0000
0000600  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
           0000    0000    0000    0000    0000    0000    0000    0000
*
dd: reading `/tmp/292': Cannot allocate memory
1+0 records in
1+0 records out
1024 bytes (1.0 kB) copied0002000
, 0.0234027 s, 43.8 kB/s

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Looks somthing has overwritten the tape - I hope @mph999 can assist me.

If we look at the records:

This seems to be a Netbackup header - it says "BP backup header"

0000320   A       B   P       B   a   C   k   U   p       H   e   A   d
0000340   E   r  \0   S   N   _   A   r   c   h   i   v   e   _   S   M

But hey - here is a Openmind archive here. Does Openmind ring a bell ?     
0000540  \0  \0  \0  \0   O   p   e   n   m   i   n   d   _   A   r   c

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

@Nicolai, Do you mean O   p   e   n   m   i   n   d   _   A   r   c  overwrite the tape?

 

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Yes, it does not look like a Netbackup header.

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Is there any standart  for media header?

Where is the error?

0000540  \0  \0  \0  \0   O   p   e   n   m   i   n   d   _   A   r   c 

Cuz of  \0  \0  \0  \0  ?

Because we have  SN_Openmind policy:

# bppllist | grep Openmind
SN_Openmind
SN_Openmind_Full

Br,

Turgun

 

 

 

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

These media is used by this Policy -SN_Archive_SMSC2

The name of schedule is Openmind_Arch

#bppllist SN_Archive_SMSC2 -U

:

  Schedule:          Openmind_Arch

    Type:            User Archive

:

:

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Did someone call me :0)

Tapes, my absolute favorite topic ...

Yep, that header looks wrong, it should look like this:

0000000 V O L 1 M 0 0 0 0 2 \0 \0 \0 \0 \0 \0
0000020 \0 \0 \0 \0 \0 \0 \0 001 \0 \0 \0 024 Y - t 203
0000040 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
0000060 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \n \0 \0 \0 001
0000100 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 004 \0 \0 \0 \0 \0
0000120 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
*
0000160 T h I s I s A B P t A p
0000200 E h E a D e r \0 \0 \0 \0 \0 \0 \0 \0
0000220 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0

... something appears to have overwritten it.

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Thanks for valuable feedback @Nicolai and @mph999

How should I proceed in this situation?

Is there no chance to recover the data?

 

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Not via NBU as it will refuse to even mount the tape.

You could try and dd the data off the tape, depending on where the logical eot (end-of-tape) marker is though, the drive itself will refuse to read past that point, even if there is further data on the tape.  EG.  Think of a full NBU tape, then you relabel it - the data is still there, you just can't get past the eot mark that was written after the new header.

This is where data recovery specialists come in - they have tape drives with modified firmware that can read past an eot mark, and get at data that is still on the tape.  Problem with ths is there is no promise of success, and it's usually very very expensive.

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Ok, Thanks @mph999

In which case, media header would be overwritten ?

This cartridge was in tape and we are not using another backup software except Netbackup.

We need to avoid similar issue in future.

Br,

Turgun

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

We cannot really answer this question, NBU didn't overwrite the tape, I know this because the NBU Backup Header is still there, at least some of it).  In fact NBU won't overwtite tapes, as it looks for the empty header to confirm it is positioned correctly -  although issues can happen if external scsi-resets cause the tape to rewind mid-backup, this is invisible to NBU and the operating system, but causes the Media and Backup headers to be overwritten (unless the overwrite is <1k which is not likely).  It is usually caused by devices sharing a tape drive (eg, NBU media server and NDMP filer) being set to use different types of scsi reservation.

If you run scsi_command -map on the tape' like this (move the tape into a drive first, as with od -c)

/usr/openv/volmgr/bin/scsi_command -map -f /dev/rmt/0cbn

You can read the tape and get an idea of what is on it (easier to read than od -c)

root@womble 22110840 $ scsi_command -map -f /dev/rmt/0cbn

root@womble 22110840 $ scsi_command -map -f /dev/rmt/0cbn
00000000: file 1: record 1: size 1024: NBU MEDIA header (TAPE03)
00000001: file 1: eof after 1 records: 1024 bytes   <<<<<<<<<<<<<<<<<<< Media header size 1024 bytes
00000002: file 2: record 1: size 1024: NBU BACKUP header   <<<<<<<<<< Backup header, also 1024 bytes
backup_id womble_1496216120: frag 1: file 1: copy 1
expiration 1497425720: retention 1: block_size 65536
flags 0x0: mpx_headers 0: resume_count 0: media TAPE03
00000003: file 2: record 2: size 32768  <<<<<<<<<<< Backup data (was a tiny backup)
00000004: file 2: eof after 2 records: 33792 bytes   <<<<<<<  (=32768+1024  = Backup data _ Media header)
00000005: file 3: record 1: size 1024: NBU EMPTY header (file 2)   <<<<< (NBU empty header)
00000006: file 3: eof after 1 records: 1024 bytes
eot  <<<<< end-of-tape mark  (logical)

Given we still see the Backup Header on your tape, then whatever spatted the Media header, was 1024 byes or less in size.

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Output of  scsi_command -map -f  on our media is :

# scsi_command -map -f  /tmp/292
00000000: file 1: record 1: size 1024: NBU BACKUP header
          backup_id geosmsc2_1449120727: frag 1: file 1440: copy 1
          expiration 2147483647: retention 9: block_size 262144
          flags 0x0: mpx_headers 0: resume_count 0: media E978L5
00000001: file 1: record 2: size 262144
00001801: file 1: eof after 1801 records: 471860224 bytes
00001802: file 2: record 1: size 1024: NBU EMPTY header (file 1441)
00001803: file 2: eof after 1 records: 1024 bytes
eot

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

OK ... so the media header is completely missing

00000000: file 1: record 1: size 1024: NBU BACKUP header
          backup_id geosmsc2_1449120727: frag 1: file 1440: copy 1
          expiration 2147483647: retention 9: block_size 262144
          flags 0x0: mpx_headers 0: resume_count 0: media E978L5
00000001: file 1: record 2: size 262144
00001801: file 1: eof after 1801 records: 471860224 bytes
00001802: file 2: record 1: size 1024: NBU EMPTY header (file 1441)
00001803: file 2: eof after 1 records: 1024 bytes
eot

I was hoping it might show some details about what is on the tape where the media header should be (that dd | od -c ) was showing, but sadly not, so I can't really tell anymore from this, apart from it doesn't look like you had a scsi rewind event, as that tends to overwrite both headers.

There is only one image on the tape, so the header could have become damaged when the header was first written (though the drive should have detected this as it reads back what is written to validate it (read head is positioned after write head)) or sometime after if the tape was manually mounted.  The image is back in 2015, so I doubt you have any logs from back then.

This is a long shot, but you could try :

mt -f /dev/tapedevice -rew

mt -f /dev/tapedevice -fsr 1  (should position te tape in front of file 1 record 2 (start of the data)

 

dd if=/dev/tapedevice bs=262144 count=1801 >/tmp/myfile.tar (count = (471860224/262144)) (rounded up)

/usr/openv/netbackup/bin/tar xvf /tmp/myfile.tar

(might need to play with the number count value)

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

@turguns

100% sure you don't have two tapes with the same label, this could explain the senario ...

Re: … cannot read media header, may not be NetBackup media or is corrupted (172)

Yes ,I am sure.

We don't duplicate the labels as it is against the backup rule.