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NetBSD's Real-Time Network Backup
jschauma writes "One of NetBSD's developers, der Mouse, was interviewed by DaemonNews about his real-time network backup system (originally presented at BSDCan 2005), where changes to your local filesystem are automatically propagated to a backup server. In his interview der Mouse tells about his idea, how it works, and of course, how cool it is."
But hasn't Sun been doing this with Solaris for at least 3 years?
Any fool can criticise, condemn, and complain, and most fools do. - Benjamin Franklin
I think the point is that it could be used for an off site backup. Raid does not protect you from Hurricanes, or even fires.
Termites, on the other hand...
Why do you have to settle for one or the other? A proper backup strategy, like any security strategy, should involve more than one technology.
Hotswappable RAID has saved my servers on more than one occasion. Likewise, the servers have also been saved by tape backups. RAID5, tape backups, and data replication all have different pros and cons.
I think it is incorrect to say RAID5 is not acceptable in any backup strategy. The more chances you get at data redundancy, recovery, and failover, the better off your organization.
I don't actually run RAID, but I've gotten some interesting stories from some (more than 1) people who do.
I'll comment on this later...
The weakest drive fails first. Power down the RAID box to replace the bad drive...
OK, this is where I start getting dizzy. If their data is valuable enough to have RAID, why were they such cheap bastards that they didn't get hot-swap drives? I've worked in a LOT of places that have RAID systems, and three of my own servers have RAID, yet to date, none of them were anything but hot-swap. Additionally, with a small amount of intelligence and a few extra dollars, the administrator always puts in a hot-standby drive that will automatically take over if a drive fails, allowing for the failed drive to be replaced at a more convenient time than 1:30am without sacrificing the redundancy. Sysadmins running really critical systems will often have multiple hot-standby drives.
The stress of the power-down and restart is enough to kill the second-weakest drive.
Now, see, here's the funny part. When you spend the bucks for SCA hot-swap drives, you actually get drives of decent enough quality that this is very rarely a problem. Even if you did have to shut the array down, which you won't because you bought proper hardware.
enough so that they've quit using RAID as "backup"
Further evidence of idiocy. RAID is not a backup. RAID allows you to keep running in the event of a specific type of hardware failure. But that is all it protects you from. Backups are still just as critical as they were before you had RAID. Anyone who uses a RAID array instead of proper backups deserves to have their data sacrificed to the gods of entropy, shortly followed by their own careers.
As for my delayed comment on the first sentence... Well, I suggest you get smarter friends.