By Heidi Biggar
No one would dispute the benefits of doing backup over a storage area network (SAN) versus over a local area network (LAN). Nor would anyone dispute the potential "killer app" benefits of taking the backup server out of the equation with a serverless implementation. But what is disputable is whether serverless backup as we know it today is worth the cost of implementing it and the complexity of managing it without a fleshed-out restore capability.
According to Phil Goodwin, program director, server infrastructure strategies, with the META Group consulting firm, in Stamford, CT, it is not worth the investmentnot now, anyway. "I advise clients to hold off on purchasing this technology," says Goodwin. Implementation and management issues aside, serverless restore capabilities just aren't what they should be or need to be, he says.
The concept is simple: While it is great to be able to back up your data more quickly and efficiently, there is relatively little value in it if you can't also restore the data quickly and efficiently. After all, what is the purpose of backup if not to restore?
"In some instances, full-volume restore may not be efficient," says Dan Tanner, a senior analyst with Boston-based Aberdeen Group market research firm. "In general, we need to find a better way to restore filesor even better, to restore parts of files [in both serverless and non-serverless configurations]."
While full-volume restore is possible with current serverless backup options, the ability to restore at the file level is not widely available. Veritas Software says individual-file restore is possible with its NetBackup implementation, but both NetBackup FlashBackup and NetBackup ServerFree are required.
In this scenario, Veritas' ServerFree Agent pushes the backup data directly from disk to tape, while FlashBackup uses mapping and snapshot technologies to restore single files or directories. In cases where individual file restore is not needed, end users can use either the ServerFree Agent's native snapshot capabilities or some other third-party snapshot technology to recover full volumes.
CommVault, meanwhile, says its September release of Galaxy will not only enable serverless backup, but also address the restore issue, among other things.
Though the March release of Galaxy integrated key serverless code (e.g., third-party copy, or SCSI Extended Copy), company officials say they have held off on enabling serverless backup until a few other enhancements (e.g., policies that tie data to applications) were fine-tuned.
Company officials say a future version of Galaxy will not only give end users the option of restoring data at the file or volume level, but will also give them the added benefit of overall faster backup and restore and easier management. Policies will also enable users to tie data to specific applications.
"End users want high availability under all conditions, and they want to use the least amount of storage resources and labor to do that," explains Bob Hammer, president and CEO of CommVault.
Hammer says CommVault will tie its serverless capability into a broader "life-cycle data management" scheme, which encompasses archival and hierarchical storage management (HSM) as well as backup and restore.
While restore was the number-one concern among analysts (and some vendors) with the current state of serverless backup, several other vendors pointed to a variety of other issues, including SAN complexity/management and problems associated with SCSI Extended Copy.
For example, IBM Tivoli, which currently offers different types of serverless implementations, says it won't embed the SCSI Extended Copy command into SAN fabrics until later this yearat the earliest. (This type of configuration is arguably the truest type of serverless backup architecture since the copy engine [i.e., SCSI Extended Copy] runs on some type of fabric device [e.g., bridge, router, or gateway], not on a workstation.)
Tricia Jiang, Tivoli's technical attaché, says the immaturity of the SCSI-3 protocol, robustness issues with the fabric devices needed to push the data back and forth, and general lack of interest by end users in serverless backup are gating factors for this type of implementation.
Meanwhile, Legato, which for several years was considered to be the leader in the serverless space, has virtually abandoned its three-year-old serverless strategy, which centered on Celestra code inherited from Intelliguard Software.
Though Legato will continue to market its Celestra Workstation implementation, it will reportedly funnel its future investment dollars into further developing its snapshot capabilities, not Celestra. As for Celestra, pieces of it will find their way into NetWorker, says George Symons, VP, product management and development, at Legato.
Symons believes snapshot technologies will enable Legato to achieve many of the same goals (i.e., improved backup performance and maximum server availability) as originally expected with Celestra. Additionally, unlike serverless technology, snapshot technology is widely available among vendors and has been well-received by the end-user community.
As for Computer Associates, it says the reason its serverless options haven't been more popular has nothing to do with the technology and everything to do with the state of the SAN market. "People are focusing on getting SANs deployed and getting them stabilized, not on backup," says Nigel Turner, a vice president at Computer Associates.
Evaluating your 'serverless' options
Despite the relative lack of interest among end users in serverless backup and restore, a variety of products are available. A sampling follows:
Description: Uses third-party copy command (a.k.a. SCSI Extended Copy).
Availability: Option to BrightStor Enterprise Backup (Unix, NT, and 2000) and BrightStor ARCserve Backup (Windows NT/2000). Enterprise version also available for Oracle.
Benefits: Allows for fast data transfer and reduces host resource utilization.
Price: Enterprise version: $4,995; ARCserve version: $1,395.
Description: Third-party-copy-enabled SAN and dedicated workstation configurations.
Availability: September 2002, option to Galaxy 4.0.
Benefits: Ease of use, management, and individual file restore expected to be key features. Expect versions for specific applications (e.g., Exchange).
Pricing: Not available.
•"Application server-free" backup, which uses shared disk and split-mirror techniques. Requires no CPU cycles on application server for backup I/O.
Availability/pricing: IBM Tivoli Storage Manager for Hardware (EMC Symmetrix/Oracle and R/3 on Sun; IBM ESS for Oracle on AIX, for R/3 on AIX, and for DB/2 on AIX). From $4,500.
•LAN-free backup, which exploits the SAN. Only one backup server required. Client data can be local or SAN-attached. Backup traffic is off the LAN; reduces CPU cycles on backup server.
Availability/pricing: IBM Tivoli Storage Manager Enterprise Edition (NT/Windows 2000). From $525.
•"Server-free" backup, or third-party copy or SCSI Extended Copy. All data movement is 'outboard' of the client (see figure).
Availability/pricing: IBM Tivoli Storage Manager Enterprise Edition (limited availability). Support for Windows NT/2000 TSM server; Windows 200 TSM b/a clients. From $525.
Description: Offloads data movement from application servers. Implementation requires a dedicated "data mover workstation." Snapshot technology plays a key role.
Availability: Legato Celestra Power 1.6 (Solaris. 2.6-7, HP-UX 11.0); Legato Celestra Module for Oracle (Oracle 7.3-8i). Runs with Legato NetWorker 6.X.
Benefits: Improved backup performance; improved host resource utilization.
Price: Celestra Power: $17,500; Oracle versions: $11,500.
Description: Provides snapshot backup technology and server-free data movement. Snapshots are taken and then backed up directly from disk to tape. Uses FlashBackup for restore of individual files or directories.
Availability: NetBackup ServerFree Agent (runs on NetBackup 4.0). Support for Solaris 2.6, 2.7, 2.8, as well as various snapshot methods. Veritas FlashBackup and NetBackup can be purchased separately for improved restore capability.
Pricing: ServerFree Agent: $9,000 per server; FlashBackup: From $6,500, depending on server type.