Trend

Disk in the middle

Disk-based backup is catching on with Indian enterprises. Disks are quickly taking on the mantle of enterprise backup relegating tape to archival duty, says Abhinav Singh

While tape technology is cheaper, the cost per GB of disk is gradually coming down Sharad Srivastava Country Manager Seagate Singapore International Headquarters	SATA will definitely lead to more organisations adopting disk storage as it will continue to provide a cost-effective solution for bulk storage Yogesh Kamat Country Manager Indian subcontinent Maxtor

Indian companies—both large enterprises as well as small and medium businesses (SMBs)—have realised that the way to reduce the backup window lies in using disk-to-disk backup technology. Although tape continues to be a prime medium for long-term archival, backups are increasingly being taken onto disk due to the need for an ever shrinking backup window as critical data applications need to be restored in the quickest and the most efficient manner. Disk-to-disk backup offers faster backup, retrieval and restoration when compared to traditional tape-based backup for a very simple reason—disk is faster than tape and unlike tape, disk access isn’t sequential.

Many Indian companies are now using disk-to-disk instead of tape backup solutions. In this multi-stage process, the data is written to a disk-based backup box from where it is written to tape. This intermediate step returns control to the server or storage array so that it can do productive things such as serving up files to employees who need them urgently. It must be noted, however, that tape continues to be used for long term archival, offsite removable storage and disaster recovery.

Disk-to-disk backups shrink process time

Disk drives are available in speeds of 10,000 rpm (rotations per minute) and 15,000 rpm allowing enterprises to conduct ultra-fast backups. Sunny John, country manager, Quantum, says, “It takes two hours to backup 1-terabyte of data onto a tape whereas the same amount of data can be backed up in less than half an hour using a disk-to-disk backup.”

Tape backups are slow

The technology in tape backup is similar to cassette tape recording whereby information is written sequentially onto the magnetic surface of the tape i.e. information is written on the portion of the tape that is directly under the magnetic head while the tape is being rolled. Data access (reading and writing) on tapes requires sequential access—if the data is located at the end of the tape then accessing it will require positioning the tape to the end i.e. rewinding the tape. Sharad Srivastava, country manager, Seagate Singapore International Headquarters says, “Retrieving information via tape is slow as the magnetic tape has to be rewound so that the desired information is placed directly under the read head. A tape is prone to distortion making it difficult to retrieve data.”

Disk-based backup is more reliable

Disk-to-disk backups are more reliable, unlike tapes, which may get corrupted when exposed to heat and humidity. Hafeez Khawaja, senior regional director, Middle East, Africa & South Asia, Western Digital says, “Today, most hard disk drives come with a four to five year warranty which proves that their reliability has increased. They are more resistant to extreme climatic conditions like those prevalent in India and can be a perfect fit for effective backup gradually replacing tapes.”

SATA to make disk-to-disk popular

With the arrival of cheaper disk technologies such as SATA (Serial Attached Technology Attachment), disk drives are set to give tapes tough competition as far as data backup is concerned. SATA is a popular interface used on drives for disk backups. Yogesh Kamat, country manager-Indian subcontinent, Maxtor explains, “SATA drives are designed to offer higher data transfer rates, simpler RAID integration and faster HDD installation than their parallel ATA predecessors. Some SATA drives are also hot-plug compatible and allow for smaller system designs. The adoption and growth of SATA will definitely lead to more organisations adopting disk storage as it will continue to provide a cost effective solution for bulk storage.” Nearly 70 percent of installations in India are still on PATA (Parallel Attached Advanced Technology Attachment) and their graduation to SATA drives will take time, but the adoption of disk-based backup is expected to be rapid.

A majority of users in India still rely on tape-based backup because of its low-cost advantage. Srivastava says, “Tape technology is cheaper although the cost per GB of disk is gradually coming down and disk drives are considered portable when compared to tape.”

Potential markets

Disk-based backup is suitable for disaster recovery, imaging, document management, e-mail, archiving, broadcasting, security surveillance and information warehousing as data in such areas is required on a real-time or near real-time basis.

Both mid-sized and large companies are poised to benefit by switching to disk-to-disk backup solutions. Running backup sets on a disk-based medium such as Network Attached Storage (NAS) allows users to backup and restore a system and send the backup set over a network to another location quickly, providing enhanced off-site protection against data loss. SMBs in the entertainment vertical will also benefit from disk-to-disk backups. Banking and finance is slowly adopting disk as backup mainly through SAN (Storage Area Network) solutions as they have transaction-based applications with a requirement for large volumes of online data.

Disk-based vendors are bullish about the future of disk-based backup and they are queuing up with products that tout faster backup, higher capacity and faster retrieval capabilities. While the disk-based backup market is gaining ground, it has a disadvantage, the cost factor. The cost of disk-based backup is 30 percent higher than that of tape-based backup. Also, the awareness of disk as a backup device is low. With disks prices declining and SATA-based storage solutions coming to the fore, customers have an easier justification to move to disk-based backup solutions. Tape will continue to exist but the bottom line is that we are going to see more Indian enterprises adopting disk-to-disk backup solutions.

abhinav@expresscomputeronline.com