Guest Post by Robert Spurzem, Senior Product Marketing Manager,EMC Backup Recovery Systems
Does the new LTO-6 add fuel to the debate between and disk for long-term data retention?
In a word…no.
New LTO-6 tape drives and media are expected to ship in 2012 with the promise of new records in tape performance and capacity. LTO-6 purports a raw capacity of 3TB compressed and 8TB compressed, representing a 100% improvement in capacity over LTO-5. Those are impressive #’s but they don’t change the debate of tape vs. disk for long data retention.
Let’s consider the following:
What type of application data are you storing?
Different data types vary widely on their average file size and deduplication rates.
The advent of deduplication has changed the backup landscape. Due to the fact that backup data is highly repetitive, deduplication can achieve amazing results with backup data (20x-30x deduplication). As a result, disk has largely replaced tape as the preferred storage for backup.
Deduplication has also changed the archiving landscape. Emails, Office files, Adobe® files and other unstructured data files can be deduplicated and archived very efficiently on disk. Being stored on disk, the files are available for online access and fast search – very important considerations in this era of anytime, anywhere access to data.
Video surveillance, entertainment movies, seismic data files requiring massive amounts of capacity do not deduplicate well and remain better suited for tape when combined with disk for media editing and viewing.
How long will you store the data?
Data retention is an important question to consider. How many years will you store data? Will the data be stored for five years, ten years, or longer?
When data is stored for years, the traditional argument for tape is that it can be stored “on the shelf” without incurring power costs. Keep in mind, to access the data; you must deal with the complexity, cost, and time of getting data back before it can be accessed. With deduplication, advances in disk technology, and the decreasing cost per GB, disk continues to tip the total cost of long term retention is in favor of disk.
How will you access the data?
Next it is important to consider how will users (or your application) access the data? Will end users require online (instant) access? Will legal require search access for litigation support?
For random access, disk is superior to tape due to its technical design. Backup to disk (with deduplication), archiving and search discovery are applications where random and online (instant) read access dominates.
So, does LTO-6 change the conversation?
For certain niche markets LTO-6 may improve the economics of tape for long-term retention, but disk continues to displace tape for the majority of long-term-retention applications. Enabled by deduplication, backup, archiving, and search discovery are applications that successfully use disk for long term retention.
For long term data retention, always examine the “total cost” of disk versus tape when making your decision. Raw media cost comparison of tape and disk are almost irrelevant when compared with the associated operational costs of access times, handling, offsite storage, maintenance, capital infrastructure, and power and cooling.
