Any Downside to Differential Backups Only?
Hi there. Is there any downside to doing differential backups only without periodic full backups? The backup in question is backing up a media drive that has videos, applications, etc that I've downloaded and doesn't change often.
Thanks,
Kris
Each differential is only dependent upon the original full. As such, you only ever need the original full and the version of the diff you want to recover from - pretty simple so that makes like nice. HOWEVER... over time, your diffs can be just as big as your original full since the OS will be changing, you'll be adding new data everday, etc. etc etc. It probably makes sense to do a new full at some point to keep your diffs from going larger and larger each day.
There's really no advantage to sticking with diffs forever and it doesn't make sense to do so for too long. Not sure how often you plan to run backups - daily, weekly, monthly? If you're waiting an entire month between backups, you might as well do fulls (for an OS) anyway. If you're doing a weekly, it might make sense to do an initial full, followed by 4 diffs (another months worth) and then a full again and repeat. With such a plan in place, you can have the software keep a certain # of version chains (example 1 full + 4 diffs = one version chain in my weekly example above). Set the automatic cleanup to only keep the # of version chains you need/want (that could be 1, 2, 3, 4, etc.... usually depends on how much retention you want and/or how much space you have available for the backups to keep growing).
Thanks FtrPilot. My guess is that I would need to delete some of the differential files at some point. I'm backing up 500GB of data to a blank 1TB drive so the backup drive will fill up eventually. Based on the size of the source and target drives, I also don't think I can save more than one full backup.
Is there a better way to set up the backup in your opinion? If I delete some of the incremental files, will I get one prompt for every file that's missing?
Thanks Bobbo. The source is a data drive where I keep media like video and application files that I download. It doesn't change often - maybe three or four new files per week and periodic deletes when I remove stuff that I don't need any more. Is there a way you would recommend configuring the backup given that?
Keep in mind that differentials and incrementals are different backup methods. Diffs are backups of everythign that has changed since the last full. Example Dif 1 will include all changes since the last full. Diff 2 will include all changes since the last full as well. In order to recover, just pick the diff you want, it will look at the content in the full and itself and restore that.
Incrementals only backup changes since the last incremental. Example. Inc1 backup contains all data since the last full. Inc2 inclues all data since the last incremental. In order to recover, pick the incremental you want, it will look at the content in the last full plus the content in each inc that came before it.
With a 1TB drive, it might be tight to get more than 1 full - but maybe not. Acronis uses compression. It really depends on how much data has changed with each backup as that will determine how big each additional Inc or diff will become. Using Inc's will save you space. Diff's tend to be more reliable and faster to recover from though so it can be a trade off.
In your case, based on limited space for backups, I would use INC backups. I would take daily backups. The scheme would be 1 full + 6 incrementals (1 week). Automatic cleanup would be set to retain 2 version chains (if they fit - you'll have to try this out to see if it can work - if not, you'll have to cut back to only retain 1 version chain).
Just read your reply. If it' mostly media, compression won't help much since pictures and videos are generally compressed already anyway. Your backups should be fairly close to the original size of the data.
And since the content doesn't change much, you should be able to expand your backup time frame as well - really up to you though. Maybe a single weekly backup as an incremental or a diff - possibly a monthly one if you can go that long (I have a software repository and only do monthly diff's on it keeping 6 versions in the chain (approximatey 6 months worth before doing a new full, since the content doesn't change often).
Is there a better way to set up the backup in your opinion? If I delete some of the incremental files, will I get one prompt for every file that's missing?
I am sure you miss typed, but intermediate differential files can be deleted. Intermediate incremental files cannot be deleted. If you decide to delete intermediate differential files, then need to perform a restore, you will get prompted numerous times to hit "<Cancel>" for each missing file. The restore will eventually start, but you will have to continue to hit "<Cancel>" until it does.
Bobbo has provided some excellent advice...
First thing you should do is perform a full backup and see how big the full backup is. If it is greater than 500Gb then I would strongly recommend getting a bigger drive to store the backups. If the full backup is greater than 500GB, then you would have to delete the previous full backup in order to start a new backup cycle....and that is not recommended.
If the first full backup is around 400Gb, then you may be able to get away with the 1TB backup drive...but you would have to pay attention to disk space when you start a new full backup. The biggest cause of corrupted database (.tib) files is running out of disk space during the backup.
Hope this helps, and let us know how things progress.
Regards,
FtrPilot
.... It doesn't change often - maybe three or four new files per week and periodic deletes when I remove stuff that I don't need any more.
One of the great features of differential and incremental backups, is that if you accidently remove the wrong file, you can "Mount" the differential or incremental backup file (double click using Windows Explorer) made prior to the accidental delete. Then navigate to the folder where the file was and copy it back to the desired location. This has saved me alot.
Regards,
FtrPilot
Thanks Bobbo and FtrPilot. I set up my backup this way:
- Schedule: Weekly
- Backup Scheme: Incremental, create a full version every 4 incremental versions, store no more than 2 recent version chains.
If I understand everything you said correctly, this should allow me to roll back / restore up to two months ago - assuming that I can fit two version chains on the 1TB drive. I also understand that I shouldn't delete any of the incremental files as they will be required to mount/restore.
I agree with what you've said about the space available on the backup drive and the fact that I'll probably have to get a bigger one. The source drive can actually fit up to 1TB so that definitely won't work if the drive has more data on it than is currently there.
Thanks again for all your help. If you have any further recommendations based on what I wrote, I'm all ears. :)
Sounds like a sound plan. I have a feeling the 1TB drive won't be big enough though. In order for the version chain cleanup to run, that third full must be able to complete first. Once that third full is done, then it will delete the original version chain. You can get a cheap 2TB drive for less than $65
http://www.amazon.com/Seagate-Desktop-3-5-Inch-Internal-ST2000DM001/dp/…
4 and 5TB external drives are about $130 and will have a case and power already too. Just keep in mind that most external drives are 5400RPM to cut down on heat and extend life. Cheaper drives are usually slower so you give up some performance for increased storage. For backups and archives, this is usually a good tradeoff, but will result in longer backup times. If 2TB SSD's were the same price, it would be a no-brainer, but then again a 2TB SSD is still like $700.
Kris,
I believe you have an excellent plan. If you get the $65 hard drive, linked by Bobbo, then I would recommend a USB 3 docking station like the one below:
http://www.amazon.com/Kingwin-2-5-Inch-3-5-Inch-Clone-EZD-2537U3/dp/B00…
Backing up to an external drive has some advantages...the drive can be connected only when needed. This could reduce your exposure to malware threats. The docking station allows you to buy the less expensive 3-5 inch drives. You can easily remove the drive and store it off site, for further protection.
Regards,
FtrPilot