Hp Lto-3 Ultrium Data Cartridges Comparative Brand Testing

The HP LTO Ultrium media cartridge is designed and manufactured to optimize both media and drive performance. HP conducted an experiment among different brands of LTO 3 ultrium backup data cartridges. The tests prove that users of HP LTO3 Ultrium data cartridges could obtain twice the data capacity per backup and significantly greater reliability. HP branded LTO3 Ultrium data cartridges provided upto three times as many continuously successful backup and restore cycles. The price of HP LTO-3 Ultrium cartridge is less than the other competing brands. Testing in extreme climatic conditions have demonstrated the reliability of HP LTO Ultrium media, where data has been fully recovered from tapes that have withstood the world’s most extreme environments.

The test engineers took four LTO3 Ultrium RW cartridges. The two tapes were from HP and two from another leading brand and tested them in four HP StorageWorks Ultrium 960 drives. They test was conducted in a controlled environment of 74ºF and relative humidity of 15%.

In the first stage of the test procedure, the cartridges were put through 100 continual full volumes, 400-GB native capacity, backup and restore cycles. This means that the total was 200 full-volume operations. The bit error rate BER was measured every 2 GB throughout the process.

Data error rates provide the most informative measure of performance. The data rate also relates to how the tape is manufactured, the signal characteristics of the tape, its quality of coating, and the surface roughness. If the error rates are high, the drive has to work hard to verify that data is being saved or restored properly.

High error rate occur when the signal becomes noisy and distorted. In the worst case, error rate levels ultimately reach a point where the drive cannot cope with correcting mistakes and data may be lost altogether.

HP has developed proprietary software for the HP drives, this software acts like a powerful tape microscope and allows the user to analyze the performance of the backup and restore cycles in far more detail than would otherwise be possible using off the shelf backup applications. In order to ensure that the results of the testing procedure were not overly influenced by the performance of individual drives, the HP LTO3 Ultrium cartridges in the Drives were exchanged with the other leading brand tape cartridges for the second stage of the tests.

In the second stage of the tests, the backup tape cartridges were once again tested throughout 100 continual full volumes, 400-GB native capacity. The backup, restore cycles and the bit error rate was again measured every 2 GB throughout the process. This brought the total number of backup and restore cycles throughout the entire test to 400 (200 full-volume backup cycles and 200 full-volume restore cycles). The average error rates were then calculated for each full volume and any variation in performance during the course of the tests could then be easily determined by observing any change in error rate.

The results for each of the two HP LTO3 Ultrium cartridges, in each of the drives in which they were tested, showed consistently low and stable error rates throughout the 200 continual backup and 200 continual restore cycles. The amount of the data backed up each cycle was also measured to ensure that the backup cartridge was continually providing the full maximum 400 GB of data available. After writing 80,000 GB of data, the HP cartridges were still providing optimum performance and maximum capacity without risk of data loss.

The results for each of the two Other Leading Brand cartridges, in each of the drives in which they were tested, were equally as consistent but showed a very different picture. After just 30 full backup and 30 restore cycles, less than a third of the way through the first stage of the test, performance began to degrade. After no more than 60 continual backup and 60 restore cycles, the error rates were so high, on both cartridges, that it was no longer possible to complete a full 400-GB backup operation.

Two different types of failures occurred in the tests. These failures were directly related to the poor error rate performance. Both failure types meant that it was not possible to back up the maximum 400 GB of data. The first type of failure occurred as a result of reaching the end of the tape before completing the full capacity 400 GB backup operation.

Numerous repeated attempts to write some of the original data were necessary, which resulted in using more tape with the other leading brand cartridges, than was required when using the HP brand backup cartridges. The second type of failure was also related to the poor error rate performance of the other Brand cartridges. However, this type of failure was due to it no longer being possible to verify the accuracy of the written data even after repeated attempts, causing the drive to fail and abort the backup operation completely. Both types of failures meant a cleaning cartridge needed to be inserted before the test procedure could continue.

The available capacity also deteriorated with sometimes as little as 50% of the total capacity being utilized before reaching the end of the tape. Other leading brand cartridges did not complete the full 100 backup and 100 restore cycles in either of the drives in which they were tested.

The high error rates can lead to:

Reduced cartridge capacity, so you have to buy more cartridges to back up the

same amount of data.

Failed backup and restore operations because there are too many errors to correct. You lose your data.

More frequent use of a cleaning cartridge.

Lower transfer rates (that is, poorer performance) because the drive will repeatedly attempt to re-write or re-read

the same user data until it has been able to successfully verify that the written or restored data is 100% accurate.