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Does Legato Outpace NSI?: Page 3 of 5

Legato's Symons, for his part, insists that the results are legit. He also says that Legato commissioned the test not to bash NSI, but more out of scientific curiosity. “We kept hearing back from customers that we were faster, but we didn’t know what that meant,” he says. “We wanted to quantify that in a way that made sense.”

So how does the study quantify the performance differences? The tests consisted of both manual and real-time replication of data from a source to a target computer system. VeriTest conducted each of the automated replication tests at four different connection speeds: T1, 10 Mbit/s, 100 Mbit/s, and 1 Gbit/s, and found, among other things, that Legato’s software synchronously replicates data 4.92 times faster than NSI's Double-Take over T1 wide-area networks, and is up to four times faster over a 10-Mbit/s local-area network connection.

Figure 1:

Source: VeriTest

For the manual tests, VeriTest executed a full synchronization of the data from the source system to the target system, again at the four different connection speeds. The test division also carried out four incremental synchronizations, requiring writes of 0 percent, 5 percent, 25 percent, and 100 percent changed data. These tests revealed that RepliStor was 25 percent faster than Double-Take at 1 Gbit/s during the initial, full synchronization. As for the incremental synchronizations, the test showed that Legato’s software was a whopping 188 percent faster than Double-Take when 0 percent of the data had changed, and 12 percent faster after 100 percent of the data had changed.

Figure 2: Elapsed Times for Manual Replication in Seconds

Source: VeriTest