Important with using the TAR command :
Verifying Data as It is Stored
option -W
option --verify
Attempt to verify the archive after writing.
This option causes tar to verify the archive after writing it. Each volume is checked after it is written, and any discrepancies are recorded on the standard error output.
Verification requires that the archive be on a back-space-able medium. This means pipes, some cartridge tape drives, and some other devices cannot be verified.
You can insure the accuracy of an archive by comparing files in the system with archive members. tar can compare an archive to the file system as the archive is being written, to verify a write operation, or can compare a previously written archive, to insure that it is up to date.
To check for discrepancies in an archive immediately after it is written, use the `--verify' (`-W') option in conjunction with the `--create' (`-c') operation. When this option is specified, tar checks archive members against their counterparts in the file system, and reports discrepancies on the standard error.
Just add -W to your TAR command to make sure it's 100% OK