Main Area and Open Discussion > General Software Discussion
SyncBackSE vs. SuperFlexible
f0dder:
MirrorFolder http://www.techsoftpl.com/backup/index.php There are many real-time mirroring apps, but this one has won me over.
-tranglos (November 05, 2007, 04:24 PM)
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Do you know of any other real-time sync/mirror apps that work in the same way as MF (ie., syncing only the changes, instead of doing a full filecopy on change)? MF looks like a very bloody nice program, and might just be the answer to my needs, but I wouldn't mind having something else to compare to :)
The service takes about 7 MB, so it's not tiny, but it seems to be highly reliable. I'm not sure if mirroring is the right thing for me, since if you make a bad change and save it, the mirror will go bad too (although MirrorFolder can also zip up previous versions of the mirrors it creates on schedule).
-tranglos (November 05, 2007, 04:24 PM)
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Compare it to anything else, and you will call it tiny ;). The mfsyncsv doesn't take any CPU time when it's not syncing anything (literally - CPU time and context switches don't go up), it uses only 1meg of private bytes, etc.
There's also a shell helper thing, but I'm not sure if it's necessary. Still, that one also sits idle, and takes ~1.3meg private bytes. Not bad!
Thanks a lot for mentioning MirrorFolder!
tranglos:
MirrorFolder http://www.techsoftpl.com/backup/index.php There are many real-time mirroring apps, but this one has won me over.
-tranglos (November 05, 2007, 04:24 PM)
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Do you know of any other real-time sync/mirror apps that work in the same way as MF (ie., syncing only the changes, instead of doing a full filecopy on change)? MF looks like a very bloody nice program, and might just be the answer to my needs, but I wouldn't mind having something else to compare to :)
(snip)
Thanks a lot for mentioning MirrorFolder!
-f0dder (November 10, 2007, 05:41 AM)
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Thanks a lot, f0dder!
Please see also my other note on MirrorFolder above, regarding possible interference with an external USB drive. It's a potential deal-breaker, because the system loses data when it happens. If a fixed drive was affected in this way, the results could be catastophic. I have no hard evidence MirrorFolder was responsible, except that it had never happened before and has not occurred since I removed MF. I'll have to re-install MF and see if it happens again.
I don't know of anything to compare it with. DirSync and similar programs usually just synchronize on schedule, and a few (SecondCopy) have an option to run a job whenever files change, but this still isn't true real-time mirroring. (SecondCopy is actually a little too eager, as it starts the backup job while the changing files are still open, e.g. being written to disk, and SC cannot handle that. You can configure a retry delay, but it would be better if SC just knew to wait a bit for files to become available without reporting an error.)
There is CascadePoint by JPSoftware (of 4Dos/4NT fame), which claims to do real-time mirroring (I've only found it now):
http://www.jpsoft.com/cascadepointdes.htm
Also, ShadowProtect Desktop real-time imaging looks interesting - mentioned by Defenestration here:
https://www.donationcoder.com/forum/index.php?topic=10427.msg83068#msg83068
f0dder:
tranglos: was your external USB enclosure by any chance connected via FireWire and not USB? Delay-write errors for firewire is a known issue (I've been-close-to losing my share of data because of it, thanks for GetDataBack!), because of some buggy firewire controller chips...
But I guess it could be caused by the MF filter driver, the problem with the firewire case iirc has to do with the controller saying "I can handle X size requests" but the drive only being able to handle some smaller amount. If the MF filter driver "blindly" copies i/o request packets to the destination, perhaps it sends some that are too big. Worth investigating.
I wouldn't trust an external drive (USB or FireWire) for "always-on", and even less as an auto-sync destination... I've seen several computers where external USB drives sometimes lose connection for less than half a second - enough time that the drive icon would blink out and back in existance in explorer, and a file copy would give one of those "retry?" dialogs. But nothing I've lost data because of...
I'll take a look at ShadowProtect and the jpsoft offering, but I must say that MF looks appealing, and has okay pricing.
and a few (SecondCopy) have an option to run a job whenever files change, but this still isn't true real-time mirroring. (SecondCopy is actually a little too eager, as it starts the backup job while the changing files are still open, e.g. being written to disk, and SC cannot handle that. You can configure a retry delay, but it would be better if SC just knew to wait a bit for files to become available without reporting an error.)
-tranglos (November 10, 2007, 07:20 AM)
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Ugh, if it triggers as soon as the filesystem notification even is triggered... that would be awful. Especially because you don't get a list of changes, but have to scan the entire tree.
tranglos:
tranglos: was your external USB enclosure by any chance connected via FireWire and not USB?
-f0dder (November 10, 2007, 08:59 AM)
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Yes, definitely USB here.
But I guess it could be caused by the MF filter driver, the problem with the firewire case iirc has to do with the controller saying "I can handle X size requests" but the drive only being able to handle some smaller amount. If the MF filter driver "blindly" copies i/o request packets to the destination, perhaps it sends some that are too big. Worth investigating.
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At the time I had Backup4All copying a large folder tree (some 60 GB) to the external drive, while I was navigating other trees on the drive and deleting (also large) folders. After a couple of minutes of this Windows started displaying baloon notifications in the tray saying that delayed write failed and "data was lost". Good thing I was copying files rather than moving them. At first I thought the disk failed, but it was OK after I restarted the USB enclosure. Then the same thing happened again. The folders being copied/deleted had nothing to do with MirrorFolder's source and target directories, but I do suppose it hooks all disk operations and only does its thing on the configured folders.
I wouldn't trust an external drive (USB or FireWire) for "always-on", and even less as an auto-sync destination... I've seen several computers where external USB drives sometimes lose connection for less than half a second - enough time that the drive icon would blink out and back in existance in explorer, and a file copy would give one of those "retry?" dialogs. But nothing I've lost data because of...
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That's another possibility. The USB drive's LED did go out when the error happened. And the only way the USB drive works at all is if I connect it to a powered USB hub. When connected directly to a USB port on the motherboard, Windows does not detect it.
It's only a temporary solution, since I have a couple of leftover ATA drives from my previous system. I'll be replacing it with a two-disk NAS device in a few days.
Ugh, if it triggers as soon as the filesystem notification even is triggered... that would be awful. Especially because you don't get a list of changes, but have to scan the entire tree.
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Exactly, so it's only good for relatively small folder trees. Windows folder notification API is broken that way.
marek
DBC:
Marek -
Have you looked at Caddais BackupOnDemand? http://www.caddais.com/BackupOnDemand.shtml
It's a bit OT, but does concern the versioning issue. I've been using it for some years to back up important files as I write (particularly MS-Word ones). I bought it originally for this real-time backup feature, in which a driver monitors selected files for any changes while you are working on them and backs them up as a series of versions. This process is pretty unobtrusive and does not need, apparently, triggering by an explicit "save".
It also does periodic backups, scheduled ones and ftp. Of these latter features, I have only used the periodic backup, which is not very sophisticated.
Unfortunately, there seems to be little further program development going on AFAIK, but I have found the real-time mode very useful. I may be wrong about this, but I think Caddais BOD may operate somewhat differently from programs like FileHamster that seem to require a file to be actually saved before a version is made. OTOH, neither program makes it completely clear what they mean by "real time" backing up...
Derek
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