my Windows 10 operating system is 850 GB how much space will it take on my external drive

The amount of space required for backups depends on the compression level used. The type of files in the backup will also impact the size of the backup. For example files that are already compress, and possibly media files (viedos) which alreay use forms of compression. 

Not 100% certain if the volume of files is 850gig or that is the size of the system partition. The answer to that will affect what you can achieve.

If you use incremtal backups with appropriately specified clean-up rules, the 8TB drive should be able to meet your needs.

If you have not already done so, you should consider moving data to a separate HDD, or a least a separate partion. That will allow you to fine-tune the backup process. Use different back-up tasks for the system partition and data partition.

Ian

I have used Acronis for most every year if not all years since 2010. I have probably about 10 to 20 backups that I have made during a period. Many of them were on your cloud which I regretfully have never had access to. I'm now putting together another computer and I made promises that this time I will make a successful Acronis back from my post you can probably surmise that I have very little successful experience. I have done a lot of research trying to get the answers that I need. I have used your forum your publications and YouTube. But one of the most basic questions I could not even come close to:

If I have a system hard drive which has 850 GB of data. For my question it doesn't really matter if that is an exact number. It is only a hypothetical. I realize that there are variables involved with my hard drive and your compression methods that restrict you from giving me an exact number. I am only trying to get some kind of an idea on the direction I need to take. I'm not even concerned about incremental or anything else that lies in the future for my backup considerations. Two days ago I got the blue screen of death and had I been so fortunate to have a backup my life would've been a bit smoother. But being in the early stages of a new installation it wasn't as bad as it could have been. 

That's the need for a backup.

From what I surmise during my research I believe a clone would be an exact replica of my system drive. This leads to the first problem. My system drive is a Samson 2 TB 960 Pro. Since my Rampage V Edition 10 has only 1 M2 connection a clone is not possible. Now if I lived in a perfect world this is what I would like to do. I would like to create a system image of my operating system, files and all. As it is right now my 2 TB hard drive has only 109 GB occupied. Now you can see my concerned on how Acronis will squeeze the unused portion of the hard drive. So somewhere between 109gb and 2 TB I will end up with a number. Even if we used a guesstimate that was within half a terabyte aware I will end up that's more than I have right now.

So during my installation window system I would like to run a backup, full backup of the operating system and files every couple of hours. If I was using a 2 TB HHD which I would clone to a 2 TB HHD we would not be having this conversation, if you will. So you will be in the master you know exactly the best method for my predicament. I could very easily slap on an 8 terabyte HHD which would allow me to save many replications of my system drive. Size does matter. I could end up with four backups or 20+ backups. Also the method of the backup would be important. Again I do not have a clue as to the method. 

Hopefully you can help me out. Because until I get a qualified answer I am obligated to my colleagues not to touch the keyboard until I have an actual breathing backup.
Bob

Bob, what exact Acronis product are you using for your backup in this scenario?

The reason for asking is that your signature shows Acronis Backup 11.7, True Image Cloud, and ATIH 2016 but this is the ATIH 2017 forum?

On the point about doing a Clone, this is only possible with ATIH 2016/2017 by using the Acronis Rescue Media so that the system is fully offline from Windows, and if your internal M.2 drive is operating in RAID mode, then you would further need to create the Windows PE version of the Rescue Media and inject the Intel RST drivers for RAID support.  A Clone is a 1 to 1 drive relationship so your target drive can only be used for 1 Clone at a time, whereas if you do full disk & partitions backups of your source drive, then you could potentially store multiple such backups on your target drive, depending on the factors already stated by Ian in his post.

What I am not sure that I understand from your posts, is what exactly is the size of your source drive in terms of the used data on that drive?  In one part you state 850GB yet in another you say a drive only has 109GB used but is this the same drive here or two different drives?

850GB for your Windows 10 OS & Programs sound an extremely large installation if this is correct, or is this another area where we don't hold all the facts?  What is the bulk of the data made up of in this 850GB size?  Is this data that could be separated off from the main OS & Programs data?

I am getting ready to renew and most likely it will be Acronis True Image. The 2 TB I'm talking about is the size of my Samson 960 Pro. The 109gb is a physical space being used currently. Within a couple of days it will be approximately 130gb, leaving a great deal of space for expansion. So at this current time my only interest is to be able to do a recovery during this sensitive installation. 

I still have absolutely no idea as to the probable size of the finished product, backup. I might only have 130gb on the 2 TB hard drive with during the installation process that's what I'm dealing with. Now if I was doing he called I truly know a 2 TB system disk will require an external hard drive of 2 TB. But any other type of backup only God in Acronis  is knows what size the external hard drive would have to be.

Acronis True Image is the most likely suspect for the software to be used. Cloning will not work for me. What are my possibilities.
Bob

Not sure it this will help but here goes!

Conventional wisdom is that Acronis Normal compression will achieve an approximate 30% in total size space savings.  So a backup of 110GB would then result in a roughly 77GB backup image file.

Your backup scheme plays a part in this as well.  If you schedule backups as a full followed by 5 incrementals before the next full and your data grows by 2GB with each incremental then it works out like this - 110GB to start, add 2GB X 5 incrementals = 10GB to total 120GB for subsequent next full backup.  What you need be aware of here is that True Image in this scheme will first make the subsequent full backup of 120GB before it deletes the previous 110GB full file so in this scenario you would need approximately 240GB of space on disk to perform the task.

Enchantech has given you a rough guideline for how much compression can reduce the size of an ATI image. However, if you have potentially 850 GB on the disk, I suspect that you have a lot of media files such as audio or video. Those files will not compress much more, if at all.

If you indeed have a large media collection, I'd suggest a couple of things.

- Partition your drive, placing such media on a partition separate from the OS partition. That will enable you easily to restore the OS partition more quickly, if you ever need to. It will also dramatically reduce the size of OS backups.

- Use a different method to backup the media files, which likely don't change as often as your OS and other more frequently-used files such as work-related documents.

I partitioned my laptop drive into three partitions: OS; user data; and music. When I make ATI image backups, I backup the entire drive but select to exclude music file extensions (.flac, .m4a, etc.) I use Robocopy to mirror the music collection to an external HD, which is relatively quick because Robocopy compares the laptop drive's contents to the external backup and backs up only what has changed.

If I ever need to "roll back" my OS, such as after a problematic installation of new software, I restore just the OS C: partition which, because my big data and media files are excluded, can be done quickly.