How to twin/synch hard disks in order to avoid crying bad in case of unexpected failure and no fresh backups ready?

December 15, 2008 8:53 AM

Does it exist for consumer use? A storage device made by two (or more) twin synched separate hard disks, one for normal use and the other one for backup just in case something goes wrong? Or a software doing the same thing with two (or more) external hard disks?

I would like to know if I can buy a product like the one I'm going to describe.

Premise: I have a laptop, and it uses its internal SATA hard disk.
I have a lot of stuff on it, and I have no time - and never will have - to backup everything, every day, on DVDs, external USB hdd, etc.

I would like to be very unlikely to lose some data (or everything).
I know some day the internal HDD, or the laptop, will fail. It's electronics. There are mech parts. It simply won't last forever, it's normal.

Ok, so: I would like some kind of device, which I could connect to my laptop and see it as a normal hard disk, a storage device.
But, it should be a special one: e.g. it should be composed by at least TWO separate hard disks (but it would be nice to have the possibility of adding as many as I can buy).
Let me call them the "main" and the "backup" disk.

The main disk should be used as I normally do with the internal SATA disk. But, there should be some kind of controller synching whatever changes on the main disk, on the backup disk.

This way, if laptop brokes, I still have all my data on the external disk. And if the main disk fails, I still have everything on the backup one: so I can replace the main with a new hard disk, press a (hardware or software) button, and everything from backup to new main is copied, and they start synching again. Or, if the backup fails, I'll replace the backup disk, press a button, and voila'.
And, if the device controller breaks, I can pick one of the disks and put it in a usb external disk case and continue working as nothing happened (or until I buy a new one of this kind of special device).

I don't know if my explanation is understandable, but I hope you got the idea and you know something similar I can buy.

Another solution, if you know of one, would be a software solution which I should configure for the same business, telling it two (or more) external hard disks I want to use as main and backup devices.

Or, if you can suggest some kind of hacker solution for Windows XP, with rsynch and such things, it would be ok too.

Free software would be appreciated, but eventually if some good commercial solutions exist don't exclude them.

Thanks

posted by lion to computers & internet (11 comments total)

Drobo is a little expensive but exactly what you want.
posted by nowonmai at 8:58 AM on December 15, 2008

The magic term here is "RAID 1" which is exactly what you've described (two or more drives with exactly the same contents). Something like this (this is an example, not a recommendation) configured in RAID 1 mode will do what you want. You don't even need to press any buttons. Searching for "raid enclosure" on your favorite hardware site will get you a ton of results; I'll leave it to others here to recommend specific devices.
posted by 0xFCAF at 8:59 AM on December 15, 2008

On the software side, Unison.
posted by qxntpqbbbqxl at 9:08 AM on December 15, 2008

It's software, and the back-up and restore are not instantaneous, but I love the shit out of Carbonite. Only $50/year for unlimited off-site storage. If you have to restore a whole disk it will take some time to download everything, but if you just need a few files to get back to work it's pretty quick.
posted by Rock Steady at 9:16 AM on December 15, 2008

Yes, you've pretty much described a basic RAID setup.

HOWEVER- if I understand correctly, you want to have an external drive that backs up your laptop data, that in turn has a failover. Backing up to RAID is, IMO, a bit of overkill- the odds of your laptop and backup drive failing simultaneously are extremely slim. I prefer a more comprehensive, distributed backup strategy:

- If your mail isn't on the cloud, put it there.
- Many online backup services have free options for limited (usually ~2G) storage. I use the free option on Mozy to store my prefs and settings files. I do realize this is trickier on XP than a Mac, since stuff's a bit more scattered, but you should be able to pick through your "Documents & Settings" folder, as well as save your Registry this way.
- My iPhone is my backup for contacts and calendar data. If you don't have a phone that syncs, use Google.
- Back up your system and docs to a drive.
- Burn DVD's to archive "bulky" stuff like large graphics docs, movies, and music.
posted by mkultra at 9:17 AM on December 15, 2008

LaCie currently makes a Terabyte drive which consists of 2 swappable 500gig drives in a single enclosure. It can be configured as a single terabyte volume, or two 500gig volumes working in tandem, either as a dual-backup RAID system or just two separate drives.
posted by Aquaman at 9:21 AM on December 15, 2008

There are dozens of hardware solutions that do exactly this. I use an old, old NSLU2 hooked up to two USB drives for this. It's not actual RAID1, but it backs up the changed contents of disk 1 to disk 2 every night. There are plenty of RAID1 solutions, ranging from some Western Digital My Book terabyte drives (which contain two drives that can be used in RAID0 for 1TB, or RAID1 for 500MB), to RAID enclosures which can do RAID1 or RAID5. I like the ReadyNAS solution that Netgear recently acquired. Typically, these things have an Ethernet interface instead of, or in addition to, USB, so they can be treated like any old fileserver.

I would also recommend looking at an online backup solution, like Carbonite or Jungle Disk, because none of the above solutions will help if your house burns down.
posted by me & my monkey at 9:36 AM on December 15, 2008

Keep in mind, RAID is not designed for backups, it's designed for redundancy. If Microsoft Word corrupts that file you've spent four months working on, RAID will helpfully and automatically duplicate those corruptions as they happen to your 2nd hard drive.
posted by Jairus at 9:52 AM on December 15, 2008

Avoid the netgear SC101; it looks like it's what you need, but they implemented a bizarre windows-only network protocol that flat out doesn't work on linux or macs- plus, it runs like crap.

I'd go with carbonite if it were me; local-only backups are subject to fire.
posted by jenkinsEar at 11:41 AM on December 15, 2008

My experience with NetGear's ReadyNAS has been good so far. If you have your own (wireless or wired) network, you can quite easily make any stand-alone NAS box available through that (NAS = Network Accessible Storage). It's neat not to have to deal with any additional cables.
posted by springload at 12:20 AM on December 16, 2008

Thanks for all these answers, they were all very informative!
Now I really know what to search for and evaluate. Some of the options you've suggested seem to fit very well with my budget and my needs.

Honorable mention goes to "qxntpqbbbqxl", because probably I won't try it for this purpose but his suggested Unison is a free and open source software I didn't know, and it is very cool! (probably I'll use it for other purposes)

How good is AskMeFi?

Bye, thanks again.
posted by lion at 12:06 PM on December 16, 2008