The data integrity verification functionality, which is built into Spectra Logic’s BlueScale 11.3 management software, is designed to ensure customers will be able to retrieve data years after storing it on tape.
Spectra’s data verification is a three-step process: pre-scan, quick scan and post-scan.
The pre-scan checks each tape to verify that it can be written to, the quick scan confirms that a single track on a tape can be read and the post-scan ensures all sectors of a tape can be read.
The pre-scan occurs before data is moved from primary storage, to ensure the media is healthy. As soon as a tape drive is available, BlueScale checks it for mechanical problems, then validates that the tape is not write-protected and checks that encryption keys are not mismatched.
BlueScale’s Media Lifecycle Management (MLM) during the pre-scan checks between 30 to 40 points of health on the tape to help customers identify whether a tape is safe for storing data. The media health reporting is accessible directly from the library or through a web interface.
Immediately after data is written onto the disk, a 60-second quick scan is done via a cyclic redundancy check (CRC) or single-pass checksum on every block of data written on the outer track of the tape.
“A quick scan does a pass on the outer track and does a checksum and validation that one track is good,” said Matthew Starr, Spectra Logic’s chief technology officer. “It gives you 95% or better confidence that the data is good.”
A user can schedule a post-scan several months after data has been stored onto tape to make sure that long-term archived data read from the drive is authentic and the media isn't degrading. Starr said during the post-scan, data is read and run through a CRC algorithm to determine if it is identical to when it was written.
A post-scan can take up to two hours to complete a full checksum on all the blocks of data written on each track on a tape. BlueScale tracks media degradation in the library’s flash memory SQL database, and reports that to users. The tape library performs the post-scan process independent of the backup application normally used to read and write data to the tape. Spectra Logic recommends a post-scan every six to 12 months.
The software enhancement supports any generation of LTO tape and IBM TS1130, but not Oracle’s new StorageTek 10000C drive. It is included for free with new T-Series libraries or any T-Series library under service contract.
Data integrity verification software enhances tape capabilities
Analysts said Spectra Logic’s data integrity verification software for tape is unique for its thorough diagnostic capabilities. “I’m not aware of anyone that is doing it as comprehensively as they do,” said Robert Amatruda, IDC’s research director for data protection and recovery.
Spectra Logic also unveiled hardware enhancements to its Gen 3 library server (Spectra LS) for faster application speed and processing. It swapped out an AMD Geode processor for an Intel Atom, increasing the processor clock speed from 333 MHz to 1.6 GHz. The standard RAM was increased to 1 GB from 128 MB. The library also now has dual Gigabit Ethernet ports, as opposed to the previous 10/100 Ethernet.
If tape vendors don’t enhance tape capabilities, customers will lean more on the disk side. The only way to stay alive is if they enhance tape.
Arun Taneja, founder and senior analyst, Taneja Group
The new server also supports hyper threading, offers quicker response times on the BlueScale front panel and remote management interfaces, increased capacity to track larger number of tape media, and increased log storage for long-term reference.
Arun Taneja, founder and senior analyst for the Taneja Group, said the data integrity verification reflects tape’s role as primarily an archive medium today as disk becomes the main choice for backup.
“Now that tape is distinctly on the archive side, data can be on it for decades. You have to worry about data grooming,” he said. “Basically everything Spectra Logic is doing on tape would fall under data grooming. If tape vendors don’t enhance tape capabilities, customers will lean more on the disk side. The only way to stay alive is if they enhance tape.”