The client organization is a large public sector bank based in India with over 1,800 branches spread across the country. The bank was relying on magnetic tapes such as Linear Tape-Open (LTO), Digital Linear Tape (DLT), and Digital Audio Tape (DAT) to archive its important data.
Magnetic tape is one of the oldest data storage technologies used by organizations to archive and back up large data, owing to greater reliability, low maintenance cost and long-shelf life of over 30 years compared to hard drives.
In this case, the bank required essential data for an audit, which was archived in two DAT 72 tapes 14 years ago. Each tape had 36 GB of uncompressed (72 GB compressed) storage capacity.
However, when IT division of the organization mounted these DAT 72 cartridges on tape reader, the tapes were found to be inaccessible and showed as empty media.
Since data was vital, its secure recovery was a key concern for the organization. Anticipating that repeated attempts to access the tapes would lead to potential data loss, the company sought expertise of Stellar®.
At Stellar Data Recovery Lab, examination of the two DAT 72 cartridges revealed that they were physically affected due to moisture and dust. Inability to maintain optimal storage condition and proper cleaning of tape drives may have led to severe data loss situation.
Recover database files from 14 years old HP C8010A DAT 72 that was physically affected due to moisture and dust.
Data Recovery Challenges
Data Recovery Approach
Stellar® constituted a team of tape data recovery experts, which employed the following steps to recover data from damaged DAT 72 cartridges:
1. Examination and Diagnosis
The team examined both DAT 72 HP C8010A cartridges which follow 2:1 compression and can store up to 72 GB compressed data. The tapes were 60 meters in length and had 4 mm width.
The tapes were inserted in DAT 72 tape reader. But they were not accessible and both detected as a blank media.
The experts tried to clone DAT tape with the help of Stellar’s cloning tool, but couldn’t succeed. The cartridge was getting stuck and ejected from the tape reader after sometime.
On close examination, it was found there was moisture and dust particles due to which the tape had stuck and couldn’t unspool smoothly.
It was ascertained that physical damage caused by humidity and dust was the primary reason for HP C8010A tapes not accessible.
2. Dried DAT 72 cartridges
The experts decided to first remove moisture and dust from the reel due to which tape reader was unable to read the data.
Magnetic tape reel is made up of polymeric materials. Thus, it needs to be very carefully put to controlled temperature environment to remove moisture without inducing any chemical reaction. The tape recovery experts at Stellar cautiously dried the HP DAT 72 tape cartridges in Class 100 Clean Room Lab using propriety ‘baking’ technique. They first removed the dust and then subjected the tapes to a sustainable temperature and removed moisture.
3. Cloning of DAT 72 tapes
The next step was to clone DAT 72 tapes to facilitate data recovery process. This time the dried and cleaned tape was detected by Stellar cloning tool. Clone files of both DAT 72 tapes were created separately.
4. Extracted data from clone file
Extraction of DAT 72 data from the clone file is last stage of tape data recovery. But there was yet another challenge. When the recovery experts tried to extract data from the clone file, the software was unable to trace and recover the files properly. The extracted data was in RAW format. Some were not readable and the original names of files were also missing.
On in-depth scanning and internal study of sectors with the help of a Stellar tool, it was found, the files were large and fragmented. Most data was scattered with spaces left in between to be filled by new data. The tape recovery experts decided to manually reconstruct the blocks of files to restore them in original form.
5. Manual data recovery from clone files
Since data is written in blocks on magnetic tapes, the experts were affirm that to manually recover they will have to trace and restore the files at block/ sector level.
But this was not an easy task, as large files were scattered and it is essential to find all fragments of a file to open it correctly. The team contacted the client to know the type of data to be recovered, which could help in restructuring the scattered blocks of files. The client shared, the tape had Oracle database files. Stellar recovery experts viewed the internal structure of files, manually traced the unique file headers of database, and reconstructed them.
Next, the team used Stellar Oracle Viewer application to restore all the Oracle database files in readable format along with their original names from the rebuilt clone file.
Stellar Tape Data Recovery experts successfully recovered 100 % data from both HP C8010A DAT 72 tapes. All the Oracle database files were restored in their original form with complete integrity.
The detailed assessment and recovery report was shared with the client organization. The entire DAT tape data recovery project — from job intake and final closure was completed within the stipulated time.
The successful recovery of data from moisture damaged tape cartridges helped the client to access critical information necessary for its business.
“Our DAT 72 Tapes were inaccessible when we tried to restore the backup for our audit. we contacted stellar for accessing our data from those tape drives and we got 100% data from both tapes.”