Users rate D2D backup top priority

EMC headlines recent product introductions

By Heidi Biggar

Disk-based, or disk-to-disk (D2D), backup is arguably the hottest trend in the storage market. In fact, in a recent InfoStor reader survey, 69% of respondents said their interest in the technology was either "high" or "very high."

The growing trend toward disk-based backup was further substantiated in a survey conducted by the Enterprise Storage Group (ESG) consulting firm earlier this year, in which 53% of the IT managers polled said they planned to back up all their data to disk at some point in the future.

Users are interested in disk-based backup for the simple reason that it solves some of the longstanding problems with tape-based backup—performance, recoverability, and manageability—at a price point that is increasingly attractive to companies of all sizes.

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Also, the disk-based products that are being introduced today are increasingly reliable, including such high-availability features as RAID, redundant controllers and power supplies and, soon, removable disks.

"Too often, IT organizations weigh the cost of the additional disk space needed for [these types of technologies] against either the cost of the tape [media alone] or the cost of doing nothing, when what they should be comparing is the cost of disk-based recovery technologies against the much greater costs of downtime and personnel," says Phil Goodwin, senior program director at the META Group research firm in a report titled "Proactive Data Protection: The Best Defense is a Good Offense."

While Goodwin believes that an infrastructure built around disk-based recovery mechanisms, not tape, represents an IT best practice, he recognizes that from an implementation and affordability standpoint they are not necessarily practical for every IT organization today.

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"The associated infrastructure changes can be significant," Goodwin explains. "Not only is additional disk storage needed but updates to backup applications may also be needed. And many organizations will also need to develop new operational processes and retrain staff."

So, instead of implementing a pure disk-based recovery infrastructure, Goodwin recommends that users implement a "continuum of data protection" consisting of snapshots, local and remote mirrors, nearline disk libraries (a.k.a. disk-based backup), and tape libraries (see figure, above).

This type of continuum allows users to realize many of the benefits of a non-tape-based backup environment today, including faster restores, lower labor costs (up to 50% lower, according to META), lower operating costs, and reduced risk.

"[Disk-based backup] devices provide an intermediate step between primary storage and tape, thereby reducing the impact of tape-related failures as well as permitting data restoration at disk speeds," says Goodwin.

The concept of a data-protection continuum is analogous to what others refer to as tiered storage, which may be part of a broader information life-cycle management (ILM) strategy. However, tiered storage definitions may not include snapshots or mirroring.

However you define it, disk-based backup is getting traction in the market and is expected to gain momentum over the coming months, according to analysts. "It's a potentially huge market," says Tony Asaro, a senior analyst with the Enterprise Storage Group.

By 2007-08, META expects 80% of Global 2000 organizations to be using a continuum of data-protection and recovery mechanisms that rely primarily on high-availability disk-based recovery products for rapid business resumption.

The projected strength of this market, which is based on continuing end-user demand for better backup options (backup remains the number-one pain point among IT administrators), is driving product introductions in this space. But while there has been no shortage of disk-based backup product announcements over the past six months, analysts say that EMC's recent entry into the market should give the market an even bigger boost.

Introduced last month, EMC's CLARiiON Disk Library is a disk array that emulates a tape library. (Supported emulations currently include tape systems from ADIC, Quantum, and StorageTek.)

Aside from scalability and some of its performance and availability features, the CLARiiON Disk Library is not unlike other tape emulation systems from vendors such as Overland Storage and Quantum. (For a more complete listing of products in this space, see "Market drivers and technology trends in data protection," InfoStor, April 2004, p. 22.)

Like those products, the CLARiiON Disk Library plugs directly into a storage area network (SAN) where it emulates a tape library (see figure on the right). The disk library supports a variety of backup applications, including IBM Tivoli Storage Manager, Legato NetWorker, and Veritas NetBackup and Backup Exec. Support for CommVault Galaxy and CA ARCserve and Enterprise Backup is due this summer.

The disk library leverages CLARiiON CX300 and CX700 controllers and integrates 320GB ATA disk drives for up 12.5TB to 58TB of native capacity (or 3x more with 3:1 compression). It is designed for enterprise customers that may be using other disk-based recovery techniques like snapshots, clones, and replicas to protect data.

Explains ESG's Asaro: "EMC found that a large number of its customers were using ATA-based CLARiiON disk arrays to perform backup to disks. While this is a good solution for small amounts of data, as your backup data sets grow you need something more scalable and easier to manage."

According to EMC, the CLARiiON Disk Library can be implemented in less than two hours. "This isn't an IT project; it's an appliance," says Chuck Hollis, vice president of platform marketing at EMC.

Users can expect to see overall backup speeds improve by 30% to 60%, and restore times by up to 90%, compared to tape, according to EMC claims. The appliance has a data throughput of up to 80MBps per stream, or up to 425MBps aggregate throughput.

The disk library can be used to back up EMC Symmetrix, CLARiiON, and network-attached storage (NAS) systems as well as non-EMC primary storage. A policy engine automatically moves aged data from the disk library to tape for off-site storage; no additional server is required for this process.

Overland enhances REO

While EMC focuses on the enterprise, Overland Storage continues to roll out disk-based backup options for small and medium-sized businesses (SMBs) and remote offices. At Storage Networking World last month, Overland introduced the REO 4000, its second-generation disk-based backup appliance.

Overland introduced the REO platform last fall, based on technology the company acquired in its purchase of Okapi Software.

"The REO 4000 is faster, more flexible, and more feature-rich than the REO 2000," says Peri Grover, who's in charge of product management for the new system.

Highlights of the REO 4000 include support for Fibre Channel and iSCSI (the REO 2000 only supported iSCSI), as well as support for RAID 5. Other high-availability and reliability features include dual controllers and processors, hot-swappable disk drives, and dual power supplies and cooling units.

The system writes data in LTO-2 tape formats, which is designed to make it easier for users to run the appliance with existing backup applications; includes a virtual disk capability that enables users to customize the size of the storage targets and the type of connectivity (iSCSI or Fibre Channel); and supports Windows, Solaris, NetWare, and Linux (the REO 2000 only supported Windows).

Like the REO 2000, the 4000 includes 250GB Serial ATA (SATA) disk drives for up to 2TB of native capacity per system. A multi-streaming capability allows the REO 4000 to support as many as eight servers and a data-transfer rate of up to 300GB per hour.

Pricing for the REO 4000 starts at $13,500 for the iSCSI-only model, or $17,500 with support for iSCSI and Fibre Channel.

Spectra logic—removable disk

Users will soon have another option for disk-based backup. Spectra Logic is preparing to launch its RXT Removable Disk Media platform in the next quarter. What makes the Spectra Logic approach different is its focus on disk portability, not just performance and reliability.

"RXT gives users the best of both worlds—tape and disk," says John Woelbern, consultant for Spectra Logic. "It's more than just high performance and tape emulation; it's removable RAID media." The technology consists of RXT media/RAID TeraPacks and drives. The RXT drive is analogous to a docking system, housing the RAID controller and providing power, connectivity, etc.

Spectra Logic will first integrate the RXT technology into its T950 tape libraries, but will later offer the technology in stand-alone desktop, server, and rack-mount configurations.

Because RXT drives appear to hosts as LTO-2 tape drives and have the same physical dimensions as these drives, they can be handled by the same robotics and be used interchangeably with Tape TeraPacks equipped with SAIT, SDLT, or LTO media.

Data backed up to an RXT-configured T950 library can be left on the RXT disk media for fast retrieval, exported in RXT TeraPacks for off-site storage, or copied to tape within the T950 for vaulting. The backup process is supported by Veritas NetBackup or Backup Exec software.

RXT TeraPacks can be configured with 12 2.5-inch or two 3.5-inch SATA drives for up to 960GB or 800GB of capacity, respectively. The 3.5-inch configuration supports RAID 0 and 1; the 2.5-inch, RAID 0, 1, and 5. Up to 95 TeraPacks can be housed in a single T950 cabinet.

A 3.5-inch configuration will cost about $2,000 for 800GB, and the 2.5-inch version about $6,000 for 960GB. This means that a 40TB T950 system configured with four LTO-2 drives and 20 LTO-2 TeraPacks (200 tapes) will cost approximately $12,000 less than a similarly equipped 40TB T950 that has two LTO-2 drives, two RXT drives, 16 LTO-2 TeraPacks, and 10 RXT TeraPacks, according to the company.

This article was originally published on May 01, 2004