"Now that we back up to the SAN, we do it disk-to-disk-to-tape," Machettira explains. "We figure tape is the backup of backups when you send something outside for storage."

Terence Choy, network manager at frozen quiche manufacturer Nancy's Specialty Foods in Newark, California, has three VMware virtual servers on a single box running Microsoft's SQL Server. He replicates data instantly between 1TB primary and secondary IP SANs, both from StoneFly Inc. Daily incremental backups are sent to online backup service provider EVault Inc. in Emeryville, California. After the initial data upload to EVault, the daily data changes might be as little as 100MB. Choy uses EVault's management console to configure all the backup and restore jobs.

"It operates the same way, whether you are backing up virtual servers or physical servers," he says.

John Buchanon, senior network engineer at components manufacturer Sypris Solutions Inc. in Tampa, Florida, runs 55 servers, including five SAN-connected production VMware ESX servers and 30 production virtual machines running various flavors of Windows and Unix. He runs four to 14 virtual machines on each ESX server.

Buchanon is planning for both disk-to-disk and disk-to-tape backup once he gets additional space in the SAN. But in the meantime, he backs up data nightly to three tape drives using Backup Express from Syncsort Inc. All of the virtual servers communicate with the Syncsort master server by TCP/IP via virtual network interface cards. All of the virtual servers share one or two physical Gigabit Ethernet connections on each ESX server.