Mirroring directories?

[cessna152]

Does anyone know of any software that would mirror data from one folder to another? For example, Lets say I have Folder A and Folder B on the same computer. If I write something to Folder A it should automatically replicate itself on Folder B.

Unfortunately, RAID isn't an option.

Thanks for any help.

 

[0roo0roo]

yea that would be nice, i want to know too, automatic chepa selective backup.

 

[mercanucaribe]

No but there's a Power Toy that will do automatic backups.

 

[hasu]

Try MirrorFolder
I use v3.0 and love it. Unlike regular backup programs, it copies only the changed portion of the file (may be only those sectors). Description says it is like s/w raid. There are plenty of options in the new release.

 

[mike3411]

MS's latest version of Office has "Groove" folder synchronization. Otherwise, the raid tools in Linux will allow this for free =D

 

[Czar]

secondcopy 2000 or whatever version they are at now

 

[kevnich2]

Try allwaysync. It works great for me, lots of options and it's free.

 

[hasu]

Any of these software (other than MirrorFolder) works like Raid-1 (I mean real time sector to sector backup)? Looks like they are just regular backup softwares.

 

[Nothinman]

Any of these software (other than MirrorFolder) works like Raid-1 (I mean real time sector to sector backup)? Looks like they are just regular backup softwares.

Doing it sector by sector would be impossible, or at least very problematic, since a kernel mode driver would be necessary to monitor changes to the block devices and it would have to understand the filesystems on top of the block devices in order to watch just the directories you want. Essentially any benefits you might gain from doing it at that low level would be greatly overshadowed by the huge amount of extra work required.

On Linux it should be simple enough to write a perl script using inotify to watch the directories and then rsync to copy any changes in real time, I might have to give that a try some time.

 

[hasu]

Originally posted by: Nothinman

Any of these software (other than MirrorFolder) works like Raid-1 (I mean real time sector to sector backup)? Looks like they are just regular backup softwares.

Doing it sector by sector would be impossible, or at least very problematic, since a kernel mode driver would be necessary to monitor changes to the block devices and it would have to understand the filesystems on top of the block devices in order to watch just the directories you want. Essentially any benefits you might gain from doing it at that low level would be greatly overshadowed by the huge amount of extra work required.

A driver level application should be able to achieve a similar effect. I am not sure if it would be sector "to sector" because the destination sector is not guaranteed to be there. Mirror Folder claims to have "real-time mirroring".

On Linux it should be simple enough to write a perl script using inotify to watch the directories and then rsync to copy any changes in real time, I might have to give that a try some time.

That is similar to directory change notification in windows. But then to update the backup copy the whole file will have to be copied to the destination every time the change event occurs. What would happen if you do that with a database file?

 

[Nothinman]

A driver level application

That's an oxymoron.

I am not sure if it would be sector "to sector" because the destination sector is not guaranteed to be there. Mirror Folder claims to have "real-time mirroring".

I couldn't be sector to sector unless the kernel driver portion had some way to enforce the layout on both filesystems. And if it allows you to select two directories on the same filesystem that really would be impossible.

That is similar to directory change notification in windows. But then to update the backup copy the whole file will have to be copied to the destination every time the change event occurs. What would happen if you do that with a database file?

If the backup database file isn't in use it wouldn't be an issue. If it's a hot backup then yes, you would want the sync tool to go through the application controlling the database and you should be looking at some form of clustering software.

 

[Leros]

Originally posted by: kevnich2
Try allwaysync. It works great for me, lots of options and it's free.

Allway sync has started harrasing me to buy their business version. I only sync a few hundred small files ( < 20mb total) every day. Now it won't sync unless I click a little button.

 

[HeroOfPellinor]

If you have Windows XP then Raid is most certainly an option.

 

[Nothinman]

If you have Windows XP then Raid is most certainly an option.

XP can't do software RAID1 so that's irrelevant and we don't know the specifics of the situation so you can't say that it's "certainly an option".

 

[HeroOfPellinor]

Originally posted by: Nothinman

If you have Windows XP then Raid is most certainly an option.

XP can't do software RAID1 so that's irrelevant and we don't know the specifics of the situation so you can't say that it's "certainly an option".

XP Pro can, but I forgot that XP Home can't. So we're both right.

 

[Nothinman]

XP Pro can, but I forgot that XP Home can't. So we're both right.

Nope, XP Pro can't either just like Win2K Pro couldn't. I heard a rumor that Vista Ultimate could but could never prove that.

 

[hasu]

Originally posted by: Nothinman

XP Pro can, but I forgot that XP Home can't. So we're both right.

Nope, XP Pro can't either just like Win2K Pro couldn't. I heard a rumor that Vista Ultimate could but could never prove that.

raid_without_additional_hardware

Edit1: I am not sure if it is available in Pro, but it is there in Windows 2000AS
Edit2: Test setup Windows 2000 Pro 5.00.2195 SP2

 

[Nothinman]

raid_without_additional_hardware

I failed to see any mention of software RAID1 in that article.

Edit: I am not sure if it is available in Pro, but it is there in Windows 2000AS

And Pro is the sticking point, client versions of Windows don't support any redundant software RAID while the server releases do.

 

[hasu]

Originally posted by: Nothinman

raid_without_additional_hardware

I failed to see any mention of software RAID1 in that article.

Edit: I am not sure if it is available in Pro, but it is there in Windows 2000AS

And Pro is the sticking point, client versions of Windows don't support any redundant software RAID while the server releases do.

It might be only for Raid-0?

Edit: Here you go: How To Mirror the System and Boot Partition (RAID1) in Windows 2000

 

[Nothinman]

It might be only for Raid-0?

What might be only for RAID0?

 

[hasu]

Originally posted by: Nothinman

It might be only for Raid-0?

What might be only for RAID0?

Tom's hardware.
Previous post is updated with a link describing how to achieve s/w Raid-0 in Win2k.

 

[hasu]

Originally posted by: Nothinman
I couldn't be sector to sector unless the kernel driver portion had some way to enforce the layout on both filesystems. And if it allows you to select two directories on the same filesystem that really would be impossible.

Somehow Mirrorfolder does that. As far as I noticed it does not copy the whole file to the second folder. Filemon does not catch any activity of mirror folder while it works. Mirrorfolder does copy even opened files.

 

[Nothinman]

Tom's hardware.

Which makes it irrelevant since the OP wanted mirroring. When I saw it was a Tom's Hardware link I knew it was either that or the article on hacking your system to enable the redundant RAID levels which is a pretty bad idea anyway IMO.

Previous post is updated with a link describing how to achieve s/w Raid-0 in Win2k.

Actually your article is for software RAID1 (mirroring) and it requires Server or higher just like I said already.

 

[hasu]

Originally posted by: Nothinman
Actually your article is for software RAID1 (mirroring) and it requires Server or higher just like I said already.

I have updated my previous post with a link from MS on how to implement s/w mirroring in Windows 2000.

In addition I just mirrored my 10GB TrueCrypt volume to a second folder. All the changes made to the original file is available in the second volume within 30 seconds. 30 seconds was required for me to copy a few files to the mounted TC volume unmount the volume and mount the mirrored backup. That says that it does copy only the changed portions of the file. I cannot confirm if it is sector by sector. But it is completely transparent and instantaneous irrespective of the size of the file or whether it is in use. Mirrorfolder has a trial version. You might want to try that to believe it.

 

[Nothinman]

Somehow Mirrorfolder does that. As far as I noticed it does not copy the whole file to the second folder. Filemon does not catch any activity of mirror folder while it works. Mirrorfolder does copy even opened files.

No, it doesn't do it sector by sector it just copies the changed chunks within the file and rsync can do that for free so it's not like they're doing anything magical. I realize it's probably just semantics but it does matter. Windows enforces file locks though and it locks them by default IIRC so copying opened files can be a little trickier requiring things like Volume Shadow copy.

I have updated my previous post with a link from MS on how to implement s/w mirroring in Windows 2000.

Server though, it's not possible to do software RAID1 in Pro.