Mirroring one external hard drive to another

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I have two 2TB USB3 hard drives attached to this PC, a Dell XPS 8900 running Windows 10. The two drives are used to archive all sorts of files, including application installers, personal documents, more than 35,000 personal photos, etc. I’ll call the two drives A and B to keep things simple.

For years, I’ve manually kept these two drives “synced”. For example, when I archive a new batch of photos on Drive A, I also copy the same photos to Drive B. The only intentional difference between the contents of the two drives is the FileHistory directory created by Windows’ File History component. Since (as far as I’m aware) File History backs up only to one location, I haven’t tried to sync that directory on the two drives.

I would now like to automate the syncing process if possible, so that whatever changes I make on Drive A are automatically mirrored (synced?) to Drive B. I’m not looking for anything complex or expensive, just something I can set and forget to keep the two drives in sync.

Any recommendations?

–Larry

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FreeFileSync and RealtimeSync, packaged together, may be your best bet.

"Take care of thy backups and thy restores shall take care of thee." Ben Franklin, revisted

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Larry,

My preference would be RoboCopy and have it run via a scheduled task. I use this to sync/backup my Documents directory every evening at 18:30 while I watch the news.

RoboCopy batch file:

Code:

Echo Off
REM  Updated: 12/29/14
Echo.  -------- Copying BEKDocs to N: drive -------
Robocopy "[COLOR="#00FF00"]G:BEKDocs[/COLOR]" "[COLOR="#0000FF"]N:BEKDocs[/COLOR]" /MIR /XJD /R:5 /W:15 /MT:32 /V /NP /NDL /NFL /LOG+:[COLOR="#FF0000"]G:BEKDocsBatchBackupTasks[/COLOR]RoboCopy.log 
Echo.  -------- Copy Completed              -------

Of course you’d change the Source, Destination, and Log file locations as appropriate to your setup.

HTH :cheers:

May the Forces of good computing be with you!

RG

PowerShell & VBA Rule!
Computer Specs

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I already use Cobian Backup to backup my Documents directory and a few other data directories every night. However, for this purpose I’m looking more for a program that will simply keep two entire drives in sync. In fact, the sync can just go one way; whenever I change something on Drive A, the change is propagated to Drive B.

To conserve space on my boot (C:) drive, I try to keep as many documents and files, especially photos, on an external drive as possible. When I use a photo editor to process photos and create new art, I work on copies of the graphics files on Drive A. Afterward, right now, I need to remember to copy those changes to Drive B. That gets tiresome and error-prone; I want a program that will keep track of such things “automagically”.

–Larry

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Larry,

My suggestion will do just that just change the Source to drive A and the Destination to drive B. HTH :cheers:

May the Forces of good computing be with you!

RG

PowerShell & VBA Rule!
Computer Specs

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Well, check out realtimeSync which comes with FreeFileSync. The only downside is: installation includes a PUP which gives some anti-malware kittens while it prevents the PUP from being installed. Other than that, FreeFileSync, and probably realtimeSync, really work!

"Take care of thy backups and thy restores shall take care of thee." Ben Franklin, revisted

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I’ll check out all these possibilities. Thanks!

–Larry

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I just tried realtimeSync — I can’t use it because I have no idea how to construct the needed batchfile, not until I can do some trial and error this coming weekend.

"Take care of thy backups and thy restores shall take care of thee." Ben Franklin, revisted

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Just as an aside… Mirroring is a function of the drive controller so you technically cannot mirror two external drives.

4TB mirrored NAS drives have become quite common and relatively inexpensive. I have one on a home network and can access it wirelessly from any computer.

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I use RG’s method slightly modified. I use a cmd file instead of a batch file, but I run it nightly via Task Scheduler. I duplicate my Documents folder to my OneDrive folder which is on a different internal hard drive.

After that, OneDrive automatically syncs it to the cloud, and from there it gets synced back to a OneDrive folder on my NAS. In addition, I make a frequent drive image of my data drive, which is also staggered between separate machines/hard drives.

Code:

Robocopy.exe V:UsersbbearrenDocuments A:OneDriveDocuments /MIR /XJD /R:1 /W:1 /MT:64 /V /NP /LOG:V:UsersbbearrenDesktopRoboCopy.log

Always create a fresh drive image before making system changes/Windows updates; you may need to start over!

We all have our own reasons for doing the things that we do with our systems; we don't need anyone's approval, and we don't all have to do the same things.

We were all once "Average Users".

Computer Specs

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I use RG’s method slightly modified. I use a cmd file instead of a batch file

bbearren,

Habits are hard to break! Actually I also use a .cmd file but I just can’t seem to call it anything but a batch file (same language). As my wife constantly tells me I’m stuck in the 70’s!

Mark Zbikowski (MSFT)
7/21/03
The differences between .CMD and .BAT as far as CMD.EXE is concerned are:

With extensions enabled, PATH/APPEND/PROMPT/SET/ASSOC in .CMD
files will set ERRORLEVEL regardless of error. .BAT sets ERRORLEVEL
only on errors.

HTH :cheers:

May the Forces of good computing be with you!

RG

PowerShell & VBA Rule!
Computer Specs

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I understand Larry’s usage of the word mirror, as in mirroring two hard-drives. My FreeFileSync has an option to software-wise, folder & file – wise, “mirror” source onto target. While FreeFileSync does not mirror one hard-drive onto another, it does mirror the left side [source] onto the right side [target] — whether the source be one folder or one parent folder and all of the children folders.

"Take care of thy backups and thy restores shall take care of thee." Ben Franklin, revisted

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I understand Larry’s usage of the word mirror, as in mirroring two hard-drives. My FreeFileSync has an option to software-wise, folder & file – wise, “mirror” source onto target. While FreeFileSync does not mirror one hard-drive onto another, it does mirror the left side [source] onto the right side [target] — whether the source be one folder or one parent folder and all of the children folders.

One difference between true mirroring vs syncing vs copying is what happens with deleted files. If I am mirroring Drive 1 to Drive 2 and I delete a file, it will be deleted on both drives.

I’m not sure if or how file syncing software deals with that, but I rather suspect it can. I’m not a ROBOCOPY guru by any means, but I think that there is a way to do something similar (get rid of files on 2 that aren’t on 1). In either case, this is something you would want to look into.

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One difference between true mirroring vs syncing vs copying is what happens with deleted files. If I am mirroring Drive 1 to Drive 2 and I delete a file, it will be deleted on both drives.

I’m not sure if or how file syncing software deals with that, but I rather suspect it can. I’m not a ROBOCOPY guru by any means, but I think that there is a way to do something similar (get rid of files on 2 that aren’t on 1). In either case, this is something you would want to look into.

The /MIR switch in Robocopy “mirrors” a directory tree; it deletes directories (folders) and files in the destination that no longer exist in the source.

Always create a fresh drive image before making system changes/Windows updates; you may need to start over!

We all have our own reasons for doing the things that we do with our systems; we don't need anyone's approval, and we don't all have to do the same things.

We were all once "Average Users".

Computer Specs

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“…here is a way to do something similar (get rid of files on 2 that aren’t on 1)…” gsmith
Yes, FreeFileSync does that by declaring drive 1 the source, drive 2 the target, and FFS will delete files & folders, add files & folders from drive 2 to make drive 2 match 1 perfectly.

"Take care of thy backups and thy restores shall take care of thee." Ben Franklin, revisted

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