Network executives looking for ways to back up data have several new options that promise inexpensive data protection and recovery at faster speeds than their tape-based alternatives.
Among the new alternatives is Storactive's LiveServ, which lets administrators make copies as changes to data occurs, compress the data, store it to disk and then back it up to tape when time permits.
Customers now also can perform backups by quickly and continuously taking a snapshot of a disk and storing it on inexpensive Advanced Technology Attachment (ATA) or Integrated Drive Electronics (IDE) disks offered by Network Appliance, EMC, Quantum and Nexsan. IDE and ATA drives, commonly used in desktop PCs, are attractive as backups for network-attached storage devices because they are getting closer in cost to tape, which is less expensive, and their recovery capabilities are almost 100 times as fast.
"The price, capacity and reliability is making devices like cabinets of RAID not as necessary as they were two years ago. These devices represent to us a cheap, efficacious storage media," says Tom Hickman, engineering operations manager at online back-up provider Connected in Framingham, Mass.
According to industry observers, IDE/ATA drives cost about $8,000 to $10,000 per terabyte, while tape ranges from $3,000 to $10,000 per terabyte for storage access that is as much as 100 times slower.
Backing up data to tape is slow and as the amount of data on the network increases and allotting sufficient time to perform system backups may be untenable. When tape backup is occurring, application use is interrupted, leaving workers with little to do. As a result, snapshot backups and disk-based replacements, which back up data in real time, have become popular replacements for tape.
Among the advantages of employing disk-based snapshot backups are:
• Backups can occur continuously throughout the day, eliminating the need to take down the network to back up data.
• Because data is backed up more often, it is more current and less data is lost if a failure occurs.
• Data can be more quickly recovered from disk that it can from tape.
• The secondary disk, which is used as a temporary location for data, can be backed up without affecting the network's primary storage.
Snapshot backups give users all the advantages and more of real-time data mirroring. Because they take real-time images of the disk at scheduled times, if a virus hits the disk or corruption occurs, they easily can be rolled back to a point before the corruption occurred, leaving a clean system
The frequency an administrator elects to take snapshot depends on the amount of data a business can afford to lose if there is a failure and the type of data it is. For instance, if the backup is of the business-critical financial data on an Oracle database, administrators might want to schedule as many images in a day as possible. Snapshot back-up software lets as many as 92 versions of the data be taken, letting a network be backed up almost every 15 minutes, thus providing that no more than 15 minutes of data loss.
Although Hickman doesn't use snapshot backup, he understands the lure of the technology.
"We built a redundant storage mechanism before any of the technology was available," Hickman says. "If we were starting out today, we would certainly give a hard look at [Network Appliance's] SnapManager and EMC Centera because we wouldn't have had to build all the redundancy into the software we use to back up our customers."
Hickman uses EMC's ATA-based Centera to archive less-frequently used back-up data before moving it to tape.
The number of snapshots a customer takes also depends on the storage capacity available on the device, as each image can consist of the portion of data that has changed since the last snapshot was taken (called changed block snapshot) or of the entire contents of the disk.
Recent changes to snapshot backups not only take a picture of the data, but also allow the state of the system to be saved to a CD-ROM so that if a server fails, it can easily be restored without re-installing the operating system, patches, service packs and applications. PowerQuest recently announced its V2i Protector, which lets administrators perform "bare metal" restores of Windows 2000 and NT servers from CD-ROM.
Storactive's LiveServ will protect Win 2000/NT, and .Net server when it is available.
Both products compete with products already available on the market from Veritas, Network Appliance and EMC. They work with traditional back-up software from Veritas Software, Legato Systems, Computer Associates or IBM/"Tivoli.
Further, a number of vendors provide storage arrays assembled from ATA or IDE drives, whose price approaches that of tape storage. These drives, which are almost as fast and reliable as their more expensive SCSI or Fibre Channel drives, are ganged up in enclosures and, like their SCSI and Fibre Channel counterparts, can be hot-swapped when failures occur and configured as RAID drives for protection. EMC, Quantum, Network Appliance and Nexsan are a few of the vendors of ATA/IDE drives for network storage environments.
Storactive's LiveServ is $800 per server; additional modules for backing up Exchange and SQL Server are available for $800 per server. The software is available now.
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