File-based vs image backup?

Hi,

I have a couple of data partitions that I want to backup with Acronis TI 11.0. Since the complete partitions are to be backed up, I can either use an image backup or or a file-based backup.

There will be frequent changes on documents in these partitions, so I will perform many incremental or differential backups. Now, I wonder which is the better choice for this type of backup: an image backup or a file-based backup?

Are there any differences between those backup types regarding the reliability of backups? Will small data defects make an image backup inaccessible more quickly than a file-based backup?

I noticed that large image-based full backups are much faster than the corresponding file-based backups. Is this also true for subsequent incremental/differential backups?

Gregor

 

I don't know the current state of relibility between imaging and Files and Folders (FF) backup but a year or so ago imaging was much more reliable. A lot of updates have happened since then so FF may be better now.

Imaging will typically always be faster because it bypasses most of the disk's file system.

A lot of us use TI for its imaging capabilities in order to be able to restore a bootable OS in case of disaster. We do not bother to use any backup program that takes all the files and stuffs them into a proprietary container file since a failure in a critical place could render the entire archive unreadable. Our preference is to use a program that copies files to a different location in their native format - one bad file means one bad file not the whole collection. Examples are SyncBack, ViceVersa, Karen Replicator, etc. You will find there are free versions and fancier paid versions; they will do compression, incrementals, differentials, etc.

 

I have basically the same requirements and after trying a few different things I settled on full images of the partitions to backup locations on a 2nd drive. So the full and incrementals are auto maintained and I found it easy to restore either the full partition or particular files if needed.

In addition I do manual backups to DVD (until I get an ext HDD), full and incremental, and again the restores work perfectly.

 

I stopped using file based backup years ago and make full images of C: ( Operating system + programs) and full images of D: (data) instead.

Images are much quicker to make than file based backups and hence get done more often.

I don't accept the argument that imaging of operating system is ok but not for data:

(1) if it works it works - the program doesn't what it is imaging.
(2) you should make multiple images so if one fails an earlier one can be used.
(3) corrupt images that can still be mounted can be read. I have DVD images from 2001 which have aged badly yet most files can be read.

My advice is to buy several 300 to 500 gig external drives and to make full images of C: on a regular basis and daily full images of D: ( data) deleting old images as and when space becomes an issue.

 

I agree with all that, plus, like you have done, keep the odd Image as an archive for ever.

Reminds me of the old Grandfather, Father, Son archiving strategy from the mainframe days!!

 

I agree with Long View that redudancy is the key. No backup is perfectly safe, there are just some that are safer than others and I try to use these.

I use external hard disks but also CDs/DVDs for backup.

After what I read here, I will probably stick with image backups. That is what Acronis TI does best anyway.

@LongView: How can corrupt images still be read? Can they be mounted just like non-corrupt images and the "only" problem is that some files cannot be recovered from the image?

 

Gregor,
I note your question is specific to data partitions.

Question: Are these data partitions on the same disk as your system partition?

 

Yes, they are on the same hard disk because I have the data on my laptop and it only has one hard disk.

 

I haven't used DVDs for a few years now but perhaps I see corrupt images differently than others. what I mean is this - you make an image and it is fine at this point. Then you burn it to a DVD. A couple of years later the DVD has started to deteriorate and can NOT be copied to a hard drive. I used to make a DVD every day in the 2001-2003 period and some can not be copied. Anyway I found that these disks could be mounted and many files still read. Other files were unreadable but by looking at the DVD from the day before or the day after
I was able to get the files I wanted. In practice who really needs images from 10
years ago ( I still have CDs with work data).

 

I strongly believe that if you trust ATI (or whatever disk-imager) to backup your OS, then why not your data, docs, photos, music, etc.? After all, dealing with one methodology is a lot simpler than using multiple backup methods and I see no disk-imaging disadvantages when it comes to non-OS backups.

Imho the most important 'ingredient' here is to backup to an external HDD rather than to an online HDD partition or to optical disks (very slow operation, especially when restoring).

Happy New Year to All

 

appster,

I'm in the camp that uses file based backup for the data partition. My backup app runs twice daily and copies new or changed data files to the backup partition and deletes files from the backup partition that have been deleted from the data partition. Even with 100 GB of data this only takes 2 to 3 minutes. Also there are files, usually large ones, that don't need to be backed up and these can be excluded from the backup. So my backup is smaller in size than the data files.

The backup is in native format so you know you can access a file without using proprietary software, which may not work when you need it most.

I know many people prefer image backup and I'd be interested to know the specifics of how you backup your data partition.

 

One reason why I don't use synchronization software is that I want my data backups to be encrypted. ATI now provides encryption, so I can use it for that purpose.

The only other option to get encrypted backups and still use synchronization software would be to use TrueCrypt containers. However, this method doesn't work for CDs or DVDs (except for DVD-RAMs when used with a working DVD-RAM driver).

 

Hi Brian,
It all boils down to trust and convenience. Not very long ago, I used XCOPY to back up my data, docs, and photos in native format. Now I just find it easier to use the same disk-imaging backup program (I think you know which one) for everything, making use of clearly-labeled differential backups to save some time and space. There is no right way, but various methods that can get you to the same end-result. As I see it, the really important factors are habitual backup regularity and backing up to external HDDs.

Happy New Year!

 

here here Appster

Happy New Year to ALL

 

Sure do.

One problem I see with image backup is the amount of HD space needed. At some stage you need to have enough space for at least two full image backups plus the differentials. I'd also complain about the time taken to create the differential and full images compared with the few minutes to do a file backup. By the way, how often would you create a full image of the data partition and how many do you keep?

 

I create daily differentials (just takes a few minutes/day) and when the size of the differentials start to get pretty large, I create a new full backup image, starting a new 'backup set'.

Btw, we are probably getting pretty much OT with this discussion.

 

The ability to recover effectively under a wide range of conditions is just as important as making timely backups. Backing up to a proprietary format significantly limits your recovery options. Backing up to an image file reduces your recovery options to a single basket. What you're really asking here is "Should I put all my eggs in one basket?"

Image-based backups are not particularly hardy; in fact, they are considerably more vulnerable than the data that they are backing up. If you lose just a single bit out of an image you can lose the entire backup. Stringing along a set of incremental or differential images only compounds the problem, since in the case of ATI each one must be perfect for all of them to work. Search this forum for "corrupt archive" (or similar) to get an idea of what I'm talking about.

I would never recommend an imaging solution such as ATI for backing up data. I also don't recommend using ATI for file-based backups. ATI is an excellent tool for imaging and backing up your OS, but there are far better ways to back up data. I personally consider most of ATIs data backup features to be unnecessary frills and I am somewhat sorry that they have travelled so far down that road.

To some degree your choice of backup techniques depends on what you plan to do with the backups. Are they merely short-term safeguards, to be disposed of on a regular basis as fresh backups are made? If so then the concerns I am voicing will be less important to you. On the other hand, if your backups are more like archives that you may want to access several years down the road then you should pay more attention to long-term reliability and flexibility than to speed and convenience.

Suppose you need to access something out of your backups ten years from now? Suppose there is a set of photographic images that you want to recover. OK, we know that jpg files are very likely to still be around in ten years because they are used in so many different devices and applications. Assuming that Acronis Corporation is also still around and is still producing imaging software, will the then-current version of ATI be backwards compatible with your 10-year-old data? In other words, will you be able to mount your image so you can extract the specific files you are after? If not then you might have to restore the entire partition just to recover a few files, assuming that your OS of 10 years in the future uses a compatible filesystem and that the partition boundaries haven't changed again (i.e. XP vs Vista). If not, will the 10-year-old Rescue CD still work, and will it be compatible with your new hardware? "Probably not" would be my guess.

For long-term backups it's far safer and considerably more flexible to back up to a widely used non-proprietary file-based format such as zip, or even to the native file format. There are plenty of good backup programs out there that can do this, many of them freeware. If you have a good zip program you can even "roll your own". Unlike ATI, Zip is omnipresent, is supported by a great deal of software and will be around for a long time.

Some backup software even allows you to include a user-selectable amount of error-correction with each backup, which in many cases will allow you to recover from media damage and/or file corruption with no data loss whatsoever. Compare this to the risk of losing an entire image-based backup because of a single flipped bit. My advice is, don't sacrifice reliability on the altar of convenience.

 

dantz,

A very nice summary of data backup.

Even with image backups of the OS one should not trust just a single image. Most of us keep several images just in case one (or more) proves to be corrupt in the future. A few bad sectors in the middle of an image may render it unusable but a few bad sectors in a file backup may mean you lose a few files. We are talking about rare occurrences but as your data is even more precious than your OS, the same concerns apply. If you are going to use image backups of your data then at least have several.

 

I always use imaging for system and data. To keep things simple this is done in images of the whole main hard drive. I have recently changed from normal compression to none. There is still room on my imaging hard drive for nine complete images, there were previously eleven compressed images. This small change has halved the imaging time and has somewhat reduced restore times.

I have no worries about old media, obsolete backup formats or corrupt rescue CDs. There is also no problem in having all the images on one hard drive because I have a set of three main hard drives which are rotated and refreshed from current images. These restores are done up front before a disaster has even appeared on the horizon.
So my real security of system and data consist of a pair of recently restored hard drives. These are of course in native Windows format and should the original PC die for any reason they could be read and all the data be retrieved on another computer.

Xpilot

 

I don't need to suppose. In 1990 I had data Backed up to floppies. Since that time I have used tap drives, Zip, Jazz, CD, DVD External USB, numerous backup programs and for the last 4 or 5 years Acronis.

Your basic argument falls down because you are describing a situation which does not exist. No one moves from a pc world 17 years ago to the pc world of today - the move occurs increntally. So I added zip to floppieand later jazz.
The data that was once on floppie is now on hard drives. In the near future hard drives will be replaced with static drives and the data will migrate.

I also find the idea that data stored with say Acronis 10 is somehow more at risk that data stored in file format as probably theoretically true but of no practical concern. Having made thousands of images and restored thousands without incident I am happy to live with the risk. If I make an image and it fails I will next try the one before. The odds of being unable to restore are not worth considering. The speed advantage does however mean that I am far more inclined to image backup than I am to file backup.

 

Quite right.