|Question:||I am getting a !Byte error during verification. How can I track and resolve this issue?|
|Keywords:||Byte, verify error, corruption|
- Locate files that failed Bit-Level Verification
- What causes Bit-Level failures and how to track down
- Verification catalog files and locations
- Disable verify from backups
- /log/changed.V - explanation
From the LONE-TAR Main Menu type: Option 6 (Catalogs & Docs) Option 5 (Bit-level Errors Menu) Option 9 (Files that failed)
Log file '/log/changed.V' contains all files that failed verification. Several situations can cause a file to fail, and not all failures are serious. The error to be concerned about is when a file has a "Byte Count Difference". This means the file was not touched or modified from the time it was backed up till the time it finished bit-level verification.... and the file on the hard drive vs: the same file on the tape do not EXACTLY match.
The error will look like: ./usr/jeff/notes/agreement.txt, 12 blocks <!Byte>
Select Main Menu options: c ==> b ==> h for more details.
Inside the log file '/log/changed.V' contains the following file error:
./u/tpdata/eft/TBHST.I85, 20341 blocks
<!Byte> ==> Bytes differ at block 42938
The file, TBHST.I85 is the one I had so much trouble with last week.
How can this file change between backup and verify when no one else is logged on?
1. Let's see if it's the file, or a spot on the tape where this file tends to write to on the tape: [ Make sure NO ONE is on the system except 'root' ] # cd /u/tpdata/eft # cp TBHST.I85 xxxxx # sum TBHST.I85 xxxxx >>> Do the numbers match? # rm xxxxx # cp TBHST.I85 /tmp/xxxxx (I'm assuming /u is a partition) # sum TBHST.I85 /tmp/xxxxx >>> Do the numbers match? # rm /tmp/xxxxx # lone-tar Cvfb /tmp/trash.tar 20 ./TBHST.I85 # lone-tar TTvfb /tmp/trash.tar 20 >>> Does Bit-Level Pass OK? # cd /tmp # lone-tar xvfb trash.tar 20 # sum TBHST.I85 /u/tpdata/eft/TBHST.I85 >>> Do the numbers match? # rm trash.tar If everything above passes, then this proves that there are no I/O problems with this file 'TBHST.I85' when being moved around the hard drive, or even another partition. Next step is to see if to file 'TBHST.I85' by itself, can be written to the tape OK. Here we go: 2. [ Make sure NO ONE is on the system except 'root' ] a. Put a blank tape in the tape drive... _not_ write protected. b. Run these commands: # cd / # lone-tar Cvfb /dev/rct0 20 ./u/tpdata/eft/TBHST.I85 ^^^^.... Specify your correct tape drive name. # lone-tar TTvfb /dev/rct0 20 >>> Does it pass bit-level verification?
|/log/LAST_Verify||Displays the verify summary of your last backup process. This could be a from a Master, Incremental, or Selective backup.
|/log/Verify_Aug.09_20:02.gz||Displays the verify summary of the backup that ran on August 9th. Since catalogs get compressed by LONE-TAR over time, you will want to uncompress the file before reading it.
To read the compressed verify catalog:
# cd /log
# gzip -d Verify_Aug.09_20:02gz
# less Verify_Aug.09_20:02
|/log/Verify_*||If you do a listing of /log/Verify_*, you will see all the verify catalogs LONE-TAR has stored.|
Although this is highly discouraged by the staff at Lone Star Software, there are cases where people are pressed for time and want to cut that time in half by removing the verify from the backup/verify process. This is how you accomplish this:
# ltmenu Select option 8 (Environment Menu) Select option 2 (Verify) edit variable #13 - Verify Backup Default setting is --> Y Set to N Select 'e' to edit Pick option #2 (Set to N)
Of all the verify file codes, only one will cause a LONE-TAR verify to fail. That is the <!Byte> error.
|LONE-TAR Verify File Code||Description|
|<!Date>||The timestamp of the archive file is different than the file on the hard drive.|
|<!Size>||The file size of the archive file is different than the file on the hard drive, AND the timestamp has changed|
|<!Not checked>||The file was not checked by the LONE-TAR Verify process|
|<!Byte>||The file size of the archive file is different than the file on the hard drive, AND the timestamp is the same.|