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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."
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.
Sounds like it's essentially a DoubleTake daemon for BSD, cool, I wonder how well it scales? Say if you wanted to fully mesh 10 or more servers or something. Sounds like it might come in handy for keeping the content in web farms in synch as well....
Obviously, RAID servers don't help you in the case of accidental deletion. And they certainly don't help if your whole computer gets blow up.
Still, you'd want to be careful with this, it would suck to back up all the temp files generated by random processes.
autopr0n is like, down and stuff.
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.'
How does this compare with Linux Network Block Device? Sounds very similar
It doesn't compare at all.
From my (quick) scan of the article - think of NBD as a replacement for NFS (well, sorta) & this as a sort of network RAID (kinda, not realtime).
They're not really alike - for linux drbd is probably closer.
My pics.
The weakest drive fails first. Power down the RAID box to replace the bad drive, so you can bring it back up and restore the data.
well, no. enterprise level raid has spinning spares and hotswappable everything. you can lose two drives and still be running as long as you get those replacements in there before number 3 goes. been there, and yes, it happened when we shut down for maintenance. In the real world catastrophic failure happens. Raid is not used as a backup usually, it is used to keep data available in the event of a hard drive failure. That is why you have a tape backup every night of the raid, and an extra set offsite somewhere. We have all heard the phrase, "a backup of the backup".
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How does this protect against an rm -rf against the filesystem... I guess it would trash the backup on the other side.
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.
This is basically RAID over the network. Personally, I can't see a lot of use for it... Just put the second drive in the machine, and use software RAID, rather than putting the second drive in a network server. Less network slowdown and congestion that way, not to mention CPU-time wasted packetizing, encrypting, etc.
As always, RAID (and now this) is not a backup solution.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
It's almost a troll to even mention it, since there are so many things pioneered by Multics....
No political party has a monopoly on wisdom or ignorance
No, but when it isn't frustrating, it's hysterical watching them try to corner the market.
until you can write a program in Lua to give me a BJ, speak for yourself