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GCN Home > 03/05/07 issue

Backup to the future

Tapes can’t take the heat, so Marines switch to disk

By Joab Jackson, GCN Staff

At some point, most storage administrators have to decide whether to archive data on tape, which is cheap but can be slow to recover, or on disk, which is speedy but more expensive.

For the Marine Expeditionary Forces, however, the choice was easy. They had to use disks, not only because disks offered faster backups, but also because tapes could not withstand the harsh climates in which the forces operate, according to Patrick McLaughlin, a Marine master gunnery sergeant at the time of this interview who has since retired.

With more than 15,000 personnel, the Marine Expeditionary Forces are deployed at 30 locations worldwide, from Iraq to the Horn of Africa. About 70 servers running Microsoft Exchange deliver the mail to the command’s headquarters in Camp Lejeune, N.C., as well as the many field units around the globe.

Originally, the command would back up the Exchange.PST mailbox files on tape drives. Each server had a tape drive, a solution that seemed to work well enough in North Carolina but did not perform as well in harsher climates. Some server facilities could heat up to 130 degrees or more, making the tapes pliable. Some would stretch when being read, becoming useless. Dusty climates also wreaked havoc.

If a device failed, forcing recovery of data from tape, nine out of 10 times “the tapes would fail, the recovery itself would fail, or the best case was the tape recovery would be successful but it would take up to 36 hours to complete the recovery process,” McLaughlin said.

Needless to say, the command couldn’t endure a 36-hour hold time for an e-mail account.

A tape-based approach had other problems: Mailboxes would be backed up once a day, which meant that a power outage at the wrong time could lose an entire day’s worth of mail. Plus, backing up all the mailboxes could take six to eight hours—a process that could slow network and mailbox use during working hours. Making backups also required personnel to be on hand to swap out tapes.

So the command looked at using low-cost network attached storage devices as an alternative. Though more expensive than tape, NAS servers can be inexpensive enough to use as a feasible alternative. The Tape Technology Council, a consortium of tape vendors, has estimated that a tape-based system can cost about a fourth of a disk-based system.

The command has purchased more than 100 FAS 250 Fabric-attached storage systems from Network Appliance Inc. of Sunnyvale, Calif. The systems offer up to 4TB of storage per unit, and the command eventually will offer its personnel an aggregate total of 100TB.

The NAS approach also lets the command back up more often. The system takes a snapshot of each user’s primary mailbox every 15 minutes. Such a snapshot usually takes only a minute or two to complete, and, after initial set-up, requires no administrator intervention.

For McLaughlin, disks provided the optimal solution to the problem of extreme environments and frequent backups. “Up to that point, we really had no solution other than to keep doing what we were doing … relying on an unreliable tactical solution [of] tape,” he said.
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