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Level 1

5 points

What's the best way to keep two hard dives synced?

I've been looking at the best way to protect my data and I've learned a few things. My first thought was RAID but a bit more research showed RAID is not a fix-all. It has it's own problems and even if I use a RAID1 or RAID10 array (depending on the number of drives) a failure in one drive can actually set off another drive, killing multiple drives and still destroying my data. There are a few other issues I've seen, such as the way you need to manage a RAID system that don't overly appeal to me.

So what I'm thinking now is two separate hard drives that are synced in some manner. Both of these drives are going to be sitting on the back of my iMac at all times so there's no real worry about their needing to be connected to back up. The question is how best to do it?

So far my options are:

Chronosync: Software wise, I know this can sync across drives and as such has been something that interests me. However, I'm not sure how powerful it is and I'm still curious about how I would have to use it.

SuperDuper: Same thing as Chronosync, really, just a different piece of software.

Rsync: To be honest, this is the one that interests me the most. I need to look into it a bit more I'm starting to think this might be a great choice for me. With some caveats.

Basically, here are the things I'm going to use it for:

Two 3–4 TB HDDs or RAID0 arrays.
Storing of general project archives, images, documents, movies, music, that kind of thing.
Possibly for system backup with Time Machine.

Now, how I'd prefer it to work is:

I keep both hard drives plugged in via FireWire cables.
Ideally, whenever I edit, add or delete a file on one hard drive the change is immediately made to the other.
Once the syncing is set up I never touch it again, don't have to.
The only time I ever have to come back to it is if I'm swapping out one or both of the drives for larger ones.
All of this is controlled by some sort of GUI

I'm willing to accept terminal commands if I have to... But I'd really prefer not to. Also, if the syncing has to be done every hour or once a day or some other similar schedule I'm willing to accept that as well, though it's not preferred.

So that's what I'm looking at doing. I'd love to hear what you guys think.

iMac, Mac OS X (10.6.7), Intel Core i7 2.93Ghz / 12GB RAM / 1TB HDD / ATI 5750HD @ 1GB VR

Posted on May 4, 2011 7:37 PM

19 replies

i3inary

Level 1

0 points

May 9, 2011 1:31 AM in response to Doug_S

I just started using goodsync today with my lg nas and it's a pretty solid combo. Goodsync can sync will all kinds of protocols remotely and has lots of options and flexibility to stay synced.

BobHarris

Level 9

53,261 points

May 9, 2011 6:26 AM in response to shoodabinacowboy

> ... format it from NTFS to the same as above, and it won't come up in Time Machine now

TimeMachine is not going to like NTFS. There are specific features in HFS+ that TimeMachine wants and depends on that are not in NTFS.

If your parent's system is also on the net, then maybe you could use "CrashPlan" to backup your stuff over the net. As long as you are using your own hardware and storage, CrashPlan is free to use.

You can also format your drives as HFS+, and then just store them at your parents, without attempting to connect them to a PC (there is Windows software that can read HFS+, but if having the disks at your parents is just to protect against loss at your house, then it is not necessary they be readable by the PC, just available should you need them).

May 10, 2011 7:05 PM in response to BobHarris

Thanks Bob. After re-reading my post I see I didn't write that very sensibly. I even read it myself and it sounded like I was saying I formatted TO NTFS..... What I was in fact trying to say is that I formatted FROM NTFS (the Seagate 500 Gig came pre-formatted that way) ------TO: Mac OS X (Journaled). So it is definitely formatted Mac-style now. The problem is that Time Machine will only see one drive at a time. And that is what I'm trying to find a work-around for.

To answer your other question, no, I do not need to access the EIDE drive at my parents' house. It will be sitting on a shelf there in an anti-static bag just in case I have a fire at MY house. The only other time it would be touched [ideally], would be if/when I replace it with another 200 Gig EIDE HD that I'd periodically run through Time Machine and take over there as an updated 'fail-safe'.

For replies' purpose, let's hypothetically assume that my computer is stand-alone, not connected to the internet or any network.....and that I have no money for any additional hardware or software...

Can it be done?

Thank You

BobHarris

Level 9

53,261 points

May 10, 2011 8:49 PM in response to shoodabinacowboy

First. My secondary (in depth) backups are not using TimeMachine. I use a disk cloning backup. Carbon Copy Cloner is highly respected and free, or you can make full disk clones using SuperDuper for free (SuperDuper wants the shareware fee if you wish to enable incremental backups). I happen to use SuperDuper, but only because I started using it before CCC reached its current level of goodness.

And I think for a disk you are taking to your parent's house, a clone of your system would be a good thing. And that would give you 2 separate backup methods so that a flaw in one, should not affect the other.

TimeMachine backup at home which gives you hourly incremental's so you can recover Oops! files, and a disk clone stored periodically at your parents. You could have the TimeMachine disk and the "Current" clone disk attached to your Mac with the clone backup (CCC) doing automatically nightly incremental updates to keep the clone in sync. Then you detach the disk when going to your parent's house taking the clone disk with you. When you return, you bring the oldest clone disk from your parents back, and hook it up to your Mac where you start cloning again.

Having said the above. I do not think TimeMachine will automatically use more than a single disk. I think if you go searching with Google, or specifically at MacOSXHints.com you may find scripts that will switch the disk TimeMachine backs up to.

I am also fairly sure you can use System Preferences -> TimeMaching -> Select disk to switch the disk TimeMachine is using at the moment. But personally I would just use the one TimeMachine disk and use a cloning backup up utility for your off-site backup storage.

By the way. The backup methods I use on my iMac are

TimeMachine to an external disk

SuperDuper to an external disk

rsync of selected key files to an external disk

At work I depend on the hourly guard rounds to detect any serious issues, plus most of my work related content is hosted on servers with corporate backup 2,000 miles away in a server farm.

As for my MacBook which goes with me to and from work.

SuperDuper backup to a Disk Utility Sparse Image hosted on my iMac at work

The .sparseimage is copied to yet another external disk on my iMac

rsync of selected key files are copied from my MacBook to yet another external disk on my iMac

(all together my iMac has about 8TB of storage at work)

If I could get corporate to give me a ton of storage on that server farm 2,000 files away, I would push an iMac backup to it, however, I actually use rsync to backup my work kept on the server farm to my iMac, just be cause I'm paranoid and do not want to loose any of my work because of an Oops by the IT guys maintaining the server farm (another reason I have so much storage on my iMac :-) )

Message was edited by: BobHarris

What's the best way to keep two hard dives synced?