When you get the 3 a.m. call that your backup server crashed, which backup software application do you want to rely on?
That's the question Blessing Hospital technical support analyst Doug Barry asked when evaluating backup applications last year. He ended up with CommVault Simpana, mainly because he felt he could trust it more than Symantec Corp. Veritas NetBackup or EMC Corp. NetWorker if he needed to perform a restore in the middle of the night. He also learned to trust CommVault Simpana more after he began using its Single Instance Store (SIS) data deduplication feature.
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"One of the key things is being able to restore that dead server at three in the morning," Barry said of the final – and decisive – test that he put prospective backup apps through. "We still have a couple of old servers running, and I wanted any late-night restores to run as smooth as possible."
Barry said he went into the Registry of a server and deleted files to crash it so it would not boot, then put the backup apps to work to see how they could restore it. "I went through the process, noting how long it took, how reassuring it was. CommVault was a lot faster, and took the guesswork out of it," he said. "I saw in the GUI where to click on the system's state and that restores everything in the Registry. Then it asks if you want to reboot the server. You know what you're restoring, what the process is and when you're done. For the other [applications], I clicked on restore server and I had to manually reboot it."
Blessing Hospital, which has two main hospitals and several clinics in Illinois, moved most of its backup to disk a few years back. Barry said he has 25 TB of data on three EMC Clariions and uses a Hewlett-Packard (HP) Co. MSA 1500 for backup – although he is transitioning his backup target to an EMC Clariion with SATA drives. Blessing has about 150 physical and virtual servers.
Once he started doing disk backups, Barry soon noticed his backups with Symantec Backup Exec began crashing more. After spending 24 hours recovering from one crash, he knew he had to upgrade his backup app. "I was looking for something more disk-to-disk friendly," he said. He looked at Symantec's NetBackup, and brought in the other two applications to do a three-way bakeoff about a year ago. He ran all three for four months, and found CommVault's backup app the fastest – but not by much. It was also the most expensive, but again, not by much – the difference between the lowest and highest prices was about $20,000. That led to the server restore tests.
According to Barry, one of the biggest factors in Simpana's backup performance was its Single Instance Store (SIS) data deduplication feature. Like most hospitals, Blessing uses a Picture Archiving and Communications System (PACS) to store digital radiation test files. Blessing has about 3 TB of PACS files, and the archiving system, says Barry, has been "our most challenging thing to back up."
More on data deduplication
While Simpana did a more reliable job backing up his PACS files than Backup Exec at the start, the CommVault application still had problems due to incompatibility with the PACS software. After he installed SIS last summer, though, the PACS backups went smoother. "When we do a huge scan of 3 TB of data, the dedupe software is saying, 'You already backed that up,'" Barry said. "It would hang with Symantec, and with CommVault [before SIS] the backup times would vary because it was getting fooled about what needed backing up."
Barry said it was easier and less expensive to go with Simpana's SIS than to install a dedicated data deduplication backup product such as a Data Domain appliance or virtual tape library (VTL) with deduplication. In this case, there wouldn't be much of a difference in performance between SIS's file-level deduplication and the more granual sub-file-level deduplication Data Domain and others use.
"For PACS files, you wouldn't see a big benefit from using Data Domain," said IDC analyst Noemi Greyzdorf. "Data Domain can't dedupe an image, it would see the image as a single object. SIS treats the image as a file, and as long as it hasn't changed, it's not going to write another copy.
"On the other hand," Greyzdorf continued, "Data Domain and other sub-file-based deduplication applications would be much better if trying to dedupe a database that's continuously changing. In large environments, you're probably going to use both file-based and sub-file-based deduplication."
Barry said he's reduced his backup volume by approximately 65% with Simpana and SIS, and his backups don't run over into the time when patients begin showing up in the morning for examinations.
"From night to night, our backup times are the same," he said. "I'm not seeing four hours of difference in the backup window some nights. Our radiology team has two main shifts that are appointment-based, running from 7 a.m. to 10 p.m. Those are bad times to be backing the server up, and they notice when the SQL Server is getting hit."