Opps we relabled all tapes buy mistake and now we need to restore 2

[LegatoLooser]

We re-labled all our LTO tapes in our tape library by mistake.
( It wasnt me! honest!)
None of the tape have been used (for backups) I would expect the data is still on the tapes, now we must restore a system. Is there anyway we can "access" the data on a tape after the existing label has been overwritten.


Here is what happens we we try to scan a tape with lots of data on it:

C:\Documents and Settings\Administrator>scanner -vvv //./Tape1
scanner: //./Tape1: No such file or directory

C:\Documents and Settings\Administrator>scanner -vvv \\.\Tape1
scanner: \\.\Tape1: opened for reading
scanner: \\.\Tape1: rewinding
scanner: Reading the label...
scanner: Reading the label done
scanner: scanning LTO Ultrium tape 000075L1 on \\.\Tape1
scanner: volume id 1049612545 record size 65536
  created  2/27/04  9:31:13 expires  2/26/06  9:31:13
scanner: \\.\Tape1: rewinding
scanner: setting position from fn 0, rn 0 to fn 2, rn 0
scanner: \\.\Tape1: opened for reading
scanner: \\.\Tape1: opened for reading
scanner: done with LTO Ultrium tape 000075L1

scanner: \\.\Tape1: rewinding

C:\Documents and Settings\Administrator>

How can we get back all our data?

 

[605]

This will not be a problem for NetWorker but for the tape drive - today's tape drives'
firmware does not allow you to move beyond the logical end-of-tape, represented
by two consecutive "file marks".

The simple question is: how much data can you loose?
- In case of none, you should bring the tape to a professional data
recovery company to solve the problem. It may cost a fortune.
- In case you do not need the beginning save set(s), you must get rid of the 2FMKs.
I did this a while ago for demo purposes:
- I started a new save set
- right after that, i switched off the drive (was a
standalone tape drive)
- When i scanned the tape there of course was a read problem at that position.
- i retried the scan skipping over this position (see scanner manpages for details)
it worked perfectly - NW will actually synchronize with the next save set.

IF YOU WANT TO DO THIS; TRY IT ON ANOTHER PIEACE OF MEDIA FIRST !

Good luck.

 

[LegatoLooser]

Well we have 70 tapes in our tape library....a professional data recovery would cost a small fortune for all tapes. And they would take a long time, we need to restore NOW! ( days like this I dont want to work in IT)

How do I identify which tape(s) (we have a Dell-136T aka Scalar 100) should have the data I need (we have 100's of systems backups to the one tape library) and can I find if that data I need was on the first chunk after the current LEOT markers?

 

[605]

Sorry, there is no way to proceed until you have solved the double FMK problem. Once
this has been corrected, you must scan the media, which takes a while as well.

If you did not overwrite recent bootstrap backups, you may recover the media db (on a test machine) -
this will informm you about the save sets and the media of your lost data.


May i also suggest that you use Auto Media Management for your jukebox.
This will prevent the need to label media in advance - NW will do it himself and he
will only use RECYCLABLE media, one at a time.

 

[Chapter11]

605, thanks for that little tidbit (re turning a drive off). I suspect it'll be of use in the future.

 

[605]

Well, i guess that a reset on the SCSI bus will have a similar result - i just
did not know how to trigger that except resetting the system as well.

I admit it is a bit weird and you should only do this on a standalone device - but it works!

 

[LegatoLooser]

Dear Forum

Well I got the 2002 tid and reviewed the steps "20.4 Recovery Data after a Media has been relabeled"

Anyway I followed the process with a standalone LTO-1 drive. Note that LTO-1 drives are fast, a 50MB file can be written very fast, no sooner than the tape is possitioned and the writing starts can the backup end successfully.
Anyway changed to using 200MB files and could follow the process....but it didnt work for me (yet?)

Basically the LTO drive is scanned with the
scanner //./Tape0 -x uasm -rv

C:\Documents and Settings\Administrator>scanner \\.\Tape0 -x uasm -rv
scanner: scanning LTO Ultrium tape JP0098L1-2 on \\.\Tape0
C:\temp\20GB2
C:\temp\20GB3
C:\temp\20GB4
C:\temp\20GB5
C:\temp\cntrlC46.dbf
C:\temp\cntrlCRS.dbf
C:\temp\cntrlSA1.dbf
C:\temp\Copy (10) of 20GB5
C:\temp\Copy (11) of 20GB5
C:\temp\Copy (12) of 20GB5
C:\temp\Copy (13) of 20GB5
C:\temp\Copy (14) of 20GB5
C:\temp\Copy (15) of 20GB5
scanner: fn 3 rn 3824 read error unknown error 23 (0x17)
scanner: fn 4 rn 0 read error unknown error 23 (0x17)
scanner: fn 4 rn 0 read error unknown error 23 (0x17)
scanner: ssid 1212019969: NOT complete
scanner: ssid 1212019969: 226 MB, 13 file(s)
scanner: done with LTO Ultrium tape JP0098L1-2

scanner: the following save sets continue on another volume:
client name  save set             save time     level   size  files   ssid    S
pstyo702     C:\temp              3/05/04 17:43    231942164     13 1212019969 S

scanner: when next volume is ready, enter device name (or `q' to quit) [\\.\Tape
0]?
scanner: starting file number (or `q' to quit) [2]? 4
scanner: starting record number (or `q' to quit) [0]? 0
scanner: continuing scan with tape on device `\\.\Tape0'
scanner: scanning LTO Ultrium tape JP0098L1-2 on \\.\Tape0
scanner: error, fsf 4: unknown error 23 (0x17)
scanner: fn 4 rn 0 read error unknown error 23 (0x17)
scanner: fn 4 rn 0 read error unknown error 23 (0x17)
scanner: ssid 1212019969: NOT complete
scanner: ssid 1212019969: 226 MB, 13 file(s)
scanner: done with LTO Ultrium tape JP0098L1-2

scanner: the following save sets continue on another volume:
pstyo702     C:\temp              3/05/04 17:43    231942164     13 1212019969 S

scanner: when next volume is ready, enter device name (or `q' to quit) [\\.\Tape
0]?

... this is an endless loop, I can never get pass this!

Basically it cannot sync the data and skip to the "old" data on my tape.

I think LTO is just "too" smart!

Any ideas....give up?

 

[605]

What you tried is a bit more complicated than what is described in that TID. In your case, the save set continues on the next media.

If this has been accidentally relabeled as well, then the same rules apply in general. However, you will have erased the beginning on the first save sets and i do not think that NW can deal with this problem at all. It can resync with the beginning of the NEXT save sets but as there is missing something in the middle of the save stream, i am pretty sure that it does not have a chance.

 

[LegatoLooser]

Thanks for your reply.

In fact I am only using one media. There is no continuation of media. Networker thinkgs there is because it cannot get pass the "problem" ie. scanner cannot sync to the media pass the point at which I turned off the drive.

The steps I performed were:

A) Take the relabled tape.
B) Mount it
C) Start a backup
D) Turn off the drive during a backup
C) Reboot the server (scsi bus reset)
D) Run the command "scanner <drive> -x uasm -rv
E) You will not that the restore does restore the backup of C) upto the point I turn off my drive.
F) Wait and then it keeps asking same "continues on new media" question.

BTW All tapes in my entire library were relabled.

 

[605]

Try it with a slight modification of your command line

scanner -f file_mark \\.\Tape0 -x uasm -rv

with file_mark = 5 ... until NetWorker can synchronize.


You may also do this by specifying a higher starting file number than 4.

 

[LegatoLooser]

Unfortunately this creates the same error

C:\Documents and Settings\Administrator>scanner -f 5 \\.\Tape0 -x uasm -rv
scanner: scanning LTO Ultrium tape JP0098L1-2 on \\.\Tape0
scanner: error, fsf 5: unknown error 23 (0x17)
scanner: fn 5 rn 0 read error unknown error 23 (0x17)
scanner: fn 5 rn 0 read error unknown error 23 (0x17)
scanner: done with LTO Ultrium tape JP0098L1-2


C:\Documents and Settings\Administrator>scanner -f 6 \\.\Tape0 -x uasm -rv
scanner: scanning LTO Ultrium tape JP0098L1-2 on \\.\Tape0
scanner: error, fsf 6: unknown error 23 (0x17)
scanner: fn 6 rn 0 read error unknown error 23 (0x17)
scanner: fn 6 rn 0 read error unknown error 23 (0x17)
scanner: done with LTO Ultrium tape JP0098L1-2


C:\Documents and Settings\Administrator>

Pretty tough problem!

 

[605]

Sorry, seems that i am stuck here. I also cannot verify the problem because i do not have a LTO tape.

Hope that Legato support can help you more.

 

[LegatoLooser]

I tried backup up a network file system removing the network cable whilst backing up , thus suspending the writing of the drive then turn off (ie no LEOT markers written) during the backup.

However same result.

BTW I am doing this on a different server, is there any config I need to check to make sure blocksize etc is the same?

 

[605]

If the block size would be different, you would not even be able to scan at all - NW will tell you that there is a difference.