During the introduction to session 3839, we were all given a disclaimer by the presenter – a disclaimer that this sessions would be a very tape heavy session. Sadly, I was hoping for some good information about the StoreOnce product. But I should have keyed in on the word archiving in the title, because the session’s core was about utilizing tape for archival and not backup purposes.
Even while disk-to-disk backup has been making huge strides for backup in recent years, tape has continued to advanced and still offers the most economical media for large data stores. Traditionally tape has not been a readily readable media since it is linear and moving from place to place takes a lot of time as tape has the wind in the cartridge, but as we found out on Friday morning, HP has not relegated tape to being past its prime.
HP is moving forward with LTO 5 and new tape drives and libraries as users need additional capacity and large stores for video and imaging applications both for backup and archiving. LTO continues to be an open standard with several media manufacturers to choose from and several tape drive manufacturers, as well.
Last week, HP introduced a new ESL G3 tape library which is capable of housing up to 15 Petabytes of data within a single library. With LTO5 cassettes holding 1.5TB of uncompressed data, or 3TB of compressed data, these tapes are becoming more and more capable of housing immense amounts of data at a cost of about $.05 per GB.
But, why is tape still relevant?
HP sees tape with a future in archival. Tape has a shelf life of approximately 30 years and these tapes are capable of housing data which will not be needed often and can be moved to a lower tier of storage where it is ok if it takes some time to retrieve. A good example of archiving would be in a medical imaging system. After 90 days (or even a year), the images are not necessarily needed to be online at all times and this data can be moved to the more economical tape, where it is still available should a request come in from a patient or doctor.
Archiving is different than backup, though I didn’t really think of it differently before this session. Archiving is storing files in a format where they are readily available to retrieve in a normal file format (just like they were on a hard drive), whereas, backup generally uses some sort of application to perform both full, incremental or differential backups and stores the data in a proprietary file format in most cases.
One of the key innovations that is allowing for archival to tape is the introduction of the LTFS file system with the LTO5 generation of media. This filesystem is written to a separate media area of the tape and allows for a tape to be mounted just like a USB drive or hard drive onto a computer system. You view it in Windows Explorer or from the command shell just like any other disk media. You can read and write to and from the tape like any other filesystem. This is really opening the avenues of allowing tape media to be used for archival purposes.
With traditional backup, you would normally have to restore the files from backup — with LTFS, you are able to read the list, find the file you want (through normal disk based search utilities) and manipulate the file as you need. Although its only a slight difference, it is a difference. No additional software is needed for an archive disk as opposed to most backup disks which require backup software of some kind to read the backups.
“Why fly your data first class when coach will do?”
One fact from the University of California at Santa Cruz that surprised me was that 95% of data is never access after 90 days. This fact helps to build a strong case for archival. Why should companies spend top dollar to keep this data online if it will never be accessed again. The fault of this argument is detailing which data should be kept online and will be needed or accessed and what will not.
Generally, when you talk about backup (or more aptly restore) you talk about recovery time objects and recovery point objectives. Once you decide upon how long you can take to restore and then at what point your restore needs to bring you to, you can choose your technology. Disk to disk, like HP StoreOnce, makes a lot of sense when it comes to backup as it improves speed of backup and speed to recover. The downside to disk-to-disk solutions is that they burn exponentially more energy than tape.
HP has also developed a full work flow around tape for the video industry. For videographers shooting in the field, they can backup their digital video onto tape, ship it to post production and then post production can use tape to ship rough cuts for review and even the final products to be output. There still seems to be a lot of potential uses because of the high capacity and low cost that tape offers.
In the interest of full disclosure, HP and Ivy Worldwide invited me and paid for my trip to HP Discover. Even though, I am trying to relay the information as impartially as possible.
