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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.
yes you are missing the point..
take 10 small servers that do the front end grunt work with 2-3 backup servers that keep complete working images of the servers and have access to their data..
a front end server dies service can roll over to a backend until the front is replaced and is quickly made jsut like the orginal a backend dies and you have a second and if all the backups die then you still have the front end to recreate the backups..
you don't normaly consider the bandwith costs as they are typicaly on a highspeed network between them and it offers you the option of replication over diffrent connections and areas..
all redundent disks help with is if a disk dies not if ram or cpu fails
some people have gotten too attached to their physical backups and tapes - personaly a backup is worthless if i can't have live access to it in a few min even if i am not physicaly at the point of failure..
this isn't particulary useful for small setups but is great for mid to large scale setups and offers plenty of room to grow.
'...if only "Jumping to a Conclusion" was an event in the Olympics.'
Also, there's "GEOM gate" on FreeBSD: http://garage.freebsd.pl/GEOM_Gate.pdf
For other cool stuff with GEOM see here and here. See also this discussion thread about ggate's limits.
-- Sig down
Termites, on the other hand...
I prefer Dirvish, and I highly recommend that people looking for a good harddisk-based backup system take a look at it. I've looked long and hard for a good backup system and this is the first that seems to fit the bill for me.
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.
Oh no! the rootkit got replicated to the backup server!