I see.  Yes, i'm probably misusing the term.  I figured JBOD meant exactly what I thought, but it's not.  What's the difference between what I'm describing and Raid-1?

Generally, JBOD refers to combining separate HDDs into effectively one bigger HDD so that data is spanned across all of them.  So if the 3rd HDD of a 5 HDD array dies, you've generally lost all data across all HDDs.  You may be able to recover files using recovery software from the other HDDs but it'll be a long process.

By definition, JBOD is non-RAID and therefore there is no data redundancy.

Actually, aren't there are two definitions for JBOD? One where data is spanned across the disks as you describe; and the other where a virtual disk manager is put on top of the "bunch of drives" but where each physical disk operates independently of the others?

If I recall correctly Goolge's G. Boudreau's Greyhole Project utilizes the second approach, but goes it one better by providing for data replication in software. Doing that makes Greyhole act much like a RAID-5 combined with an extremely flexible drive concatenation capability. This is similar to the 'Drive Extender' feature Microsoft just removed from their new Home Server release.

Last I heard it was still pre-1.0 release. But it is working and some people are using it.

Might be worth a look. (Sorry, don't have the link right this moment, but it's easy to find by - surprise! surprise! - googling 'Greyhole Project.') Link here.

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ADDENDUM: Whoops! 4wd got in there just ahead of me!  


EDIT: I stand corrected. Greyhole isn't Google's. It's the work of Guillaume Boudreau. Project website here. Personal blog here.

This is something I've been meaning to figure out, so I'm glad we're talking about it here.  This stuff is confusing, complicated, and has lots of terms.  So I'm going to try to simplify for myself.

In my situation, the storage is more so the goal rather than performance.  I say that because I'd like to keep this as simple as possible.  What I don't like about raid is the hardware requirements such as the disks having to be the same size.  I mean, it makes sense that a backup drive is the same size, I just don't like it to be a requirement.  I'd like to just cram in whatever drives I happen to find lying around.  The synchronization and all that stuff will be taken care of with software, so once again, I'd like to avoid using hardware for things software can do.  The only advantage I see in using hardware is performance.  As long as I can copy files back and forth and streamp 1080p, that's all the performance I need.

Unless I am not understanding something, I'll be staying away from RAID.  I'll be using a bunch of individual drives.  I'll use Windows 7 library tools to create folders that span multiple drives.  I'll use Super Flexible to sync my files back and forth (which I already use).  I think that's a safe, solid setup, no?

I like these other spanning ideas mentioned above by 40 and 4wd, but unless I need additional features, I'm going to keep it real simple.

I do have a question, how do all these individual drives connect to the server?  I can't imagine there's 16 SATA cables coming out the back plugging into the motherboard?  Does it use a CAT5?  Is something going on inside the box which combines it into one SATA or eSATA cable?  How does this work?

So here's part 1 of 2 blog posts I'm writing about my data loss, recovery, and backup experiences. I hope it will serve as a stern reminder to everyone to backup their important data. Not doing so could cost you 1000's of dollars or worse.

http://oshyan.blogspot.com/2010/12/seriously-people-back-up-your-data.html

- Oshyan

Pretty interesting article.  Thanks !  I wonder how a Drobo would have performed there.

There is a section on my site in the Quick Facts section about RAID types and usages. It was made up (long ago) of reproduced articles that I didn't want to lose so I could refer to them quickly if need be.

RAID Configurations

I do striping (which really shouldn't be called RAID, since it's anti-redundant) on my workstation, because I like the added speed, and only use that partition for relatively volatile stuff - and one big partition is more useful than two 74gig partitions (yes, I'm striping my raptor drivers). Definitely useful.

I mirror my fileserver, and I find this extremely useful as well - it unfortunately doesn't do hot-swap, but five minutes power-down and HDD swapping is a lot better downtime than having to restore a new drive from backup. As long as you don't use mirroring instead of backups.

But JBOD, RAID-5 or other solutions? Wouldn't even consider it.

You know, every time I come here and read the discussions about backing up, I continue to get confused.  you guys say stuff like RAID isn't for backup, and I get that.  Then you say something like:

But JBOD, RAID-5 or other solutions? Wouldn't even consider it.

And I don't quite understand what that means, really.  What's wrong with JBOD?  Why can't I just use a bunch of disks and have the files and folders synced with another duplicate drive?  So each drive has a backup drive that simply copies the files/folders.  No fancy mirroring or indexing.  Just straight up copying/moving/deleting...basic file operations.  And I can yank any drive out at anytime, plug it into another computer and see those files/folders without any extra steps.  What's wrong with that?  What have I left unaccounted for?

I'm trying to come up with the ultimate backing up solution...for HOME users.  A home user with a lot of data, yes, but still just a home user.  I want to make sure I have all of my files safeguarded against just about any situation.  If that means double or even triple redundancy, so be it.  If it means imaging or versioning, so be it.  But i always get confused whenever one of you says something like "Oh my gosh!  I would NEVER use file syncing as a backup method."  I'm like, "Why the hell not, I'm doing that!  Shit!  What's happening?!"

Anyway...

Superboy, JBOD means making a bunch of (possibly irregularly sized) drives appear as one large drive - which is pretty bad for your data if even a single drive crashes (although not as bad as striping, where your data is evenly distributed across all drives). JBOD is a raid mode, not "just stuffing a bunch of drives into a single computer".

OK, then, we keep getting confused on this JBOD.  Apparently, JBOD doesn't actually mean "Just a bunch of disks" to you guys.  When I say JBOD, I mean exactly what you jsut said: stuffing a bunch of random drives onto one system.  What is the term for that, if it's not JBOD, because I'm going to be using it a lot this year.  I don't want to keep confusing people with thinking I'm trying anything that has to do with RAID, or anything more than simply having files/folders on a disk drive.

I don't think JBOD should really be used in the context f0dder intends (although it *is* common usage to do this, which has created the confusion). SPAN or BIG are perhaps more appropriate but also more specific. The general term is concatenation. http://en.wikipedia.org/wiki/Non-RAID_drive_architectures#JBOD

Confusing, perhaps... but since it tends to be on the feature list on just about any half-assed "hardware raid" card as well as 100% software based solutions, and has been for quite a lot of years, you definitely shouldn't say "JBOD" when you really do mean Just a Bunch Of Disks

Btw, doing (windows/linux/whatever) application-based syncing between a bunch of drives in a single server sees of relatively limited use, unless you're also doing versioning. For just syncing, mirroring would be better (a purely software-based solution is fine, really, but you do want OS-level support, or at least something driver-based).