I keep running into a particular problem at customers and I'm curious if any backup software products have addressed it. Do any backup products load-balance their use of tape drives across multiple Fibre Channel ports? Click Read more to see more details.
The problem starts with having more tape drives behind each Fibre Channel port than the port can actually support. This often happens when you're sharing a bunch of tape drives between several servers. For example, say you're sharing 20 tape drives between 10 servers, and 10 are available via one FC port, and 10 are available via another FC port.
If each server gets two tape drives, everything's fine. Even if a given server grabs two tape drives on one FC port, that port can usually handle streaming two tape drives.
BUT, what if a server want's four tape drives, and is able to grab them? NOW what happens if it grabs all four tape drives from the same port? Now the four tape drives are sharing a single FC port that can only handle two tape drives.
But if the backup software were SMART, it would attempt (if it could) to grab two tape drives from each of the two FC ports. But I don't see any backup software products doing this.
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Written by W. Curtis Preston (@wcpreston). For those of you unfamiliar with my work, I've specialized in backup & recovery since 1993. I've written the O'Reilly books on backup and have worked with a number of native and commercial tools. I am now Chief Technologist at Druva, the leading provider of cloud-based data protection and data management tools for endpoints, infrastructure, and cloud applications. These posts reflect my own opinion and are not necessarily the opinion of my employer.