creating exact copys of two drives one to one external

you can use EaseUS ToDo Backup to clone the SSD first - there's a free version download at the link, nice part is it will copy it and give you the same directory tree you currently see when it's your OS drive, so if you need to go in to copy a file, or update a file, you can

after the clone, use EaseUS Partition Manager, again there's a free download, to downsize the SSD's cloned image to 256 GB, then use Partition manager to create partion of the remaining portion of the 2 TB drive and manually copy/paste the one TB drive to it

when you clone the SSD, be sure to select both "optimize for SSD" and the Sector by sector boxes.

In addition to the process recommended by Ralph, let me suggest another option for your consideration...

1. You would first create two partitions on your 2 TB USB external HDD - presumably one partition of 250 GB and a second partition covering the remaining disk-space of the 2 TB HDD.

2. Using the disk-cloning program I strongly recommend, you would clone the contents of your 250 GB SSD to the first partition of the 2 TB USB external HDD.

3. Then clone the contents of the 1 TB HDD to the second partition of the USBEHD.

4. Assuming one or both of your source drives contain an OS you would be able to boot to the OS on whichever partition on the USBEHD that the OS resides should you desire to do so. And, of course, all the programs & data contained on the USBEHD are instantly accessible.

5. Assuming you want to retain that 2 TB USBEHD for future comprehensive backups of the new system that you are contemplating, you could use the disk-cloning program as the vehicle to accomplish that.

The disk-cloning program I recommend is the Casper program. The program is extremely user-friendly with an easy-to-understand interface and straightforward design. No "learning-curve" of any consequence is necessary.

But the chief advantage of Casper is its rather extraordinary speed (in comparison with other disk-cloning programs) in undertaking its disk-cloning operations when the program is used routinely and frequently. This makes the program an ideal vehicle for a user to maintain up-to-date comprehensive backups of his/her ENTIRE system since the user now has a strong incentive to do so because he/she knows it will take only a short period of time to complete the disk-cloning operation. As an example, I back up my PC systems at least 3X a week, sometimes even daily. It usually takes me under two minutes to complete a disk-cloning operation - frequently under a minute when I clone on a daily basis. Naturally the volume of data that's cloned, the user's system, the types of drives involved in the disk-cloning process will all have a bearing on the expenditure of time to complete the disk-cloning process.

Now to the negatives...

The program is a commercial one - it costs $49.99 and AFAIK can only be obtained from the developer - http://www.fssdev.com. I realize that most PC users are exclusively interested in a "one-shot" disk-cloning program to clone the contents of an older HDD to a new larger HDD or SSD and are simply uninterested in using a disk-cloning program as a comprehensive backup tool. More's the pity but that's the situation. So the PC user can obtain disk-cloning programs that are freely available on the net and by & large they will do the one-time job. No doubt the program Ralph recommended is one of those.

All I can say is that I've never found a disk-cloning program as effective, reliable, easy-to-use, and as fast in carrying out its disk-cloning operations as the Casper program. So if you have an interest in using such a program for carrying out comprehensive backups of your system so that you can maintain up-to-date bit-for-bit copies routinely of your PC system give this program some consideration.

FYI - the reason i had recommended cloning the first smaller drive, then using partition manager to reduce the size of the partition on the 2 tb disk to 256 GB, and creating a 2nd partition on the 2 tb drive, then copying/pasting the larger storage / data drive to it, is that EaseUS will clean / erase the 1st clone if you use it to clone the 1 tb drive

will casper allow cloning a 2nd disk to that drive without it wiping the entire drive first?

Ralph:
Before I get to your specific question re Casper's capability in this matter, let me first try to review the user blackie's objective as he/she has stated it and then try to get a better understanding of the process you have outlined and how that fits in with that objective.

1. The user is currently working with two drives - a 250 GB SSD & a 1 TB HDD. Although the user hasn't stated such I suppose it's reasonable to assume the SSD contains the OS and the 1 TB HDD currently serves as a storage/backup device.

2. The user says he/she plans to "redo my whole computer", but has provided no details of precisely what's intended. But that's not "here or there" for us to discern since the user has specifically indicated what he/she wants to accomplish now.

3. Specifically, "create an exact copy of each drive onto this external (2 TB USB external HDD) so when I look through the copys (sic) I can pull out any file and it will work correctly."

The user's objective seems clear enough, yes?

4. So if relatively simple disk-cloning processes can clone both the 250 GB & the 1 TB drives to the 2 TB destination drive does that not meet the user's objective? All the data then contained on the destination drive will be immediately accessible for whatever purpose the user has in mind.

5. Since blackie gave no details about how he/she desired the 2 TB USBEHD to be set up in terms of the size of the partitions I suggested a partition of 250 GB for the SSD and the remainder of the destination drive's disk space for a second partition. Of course, blackie could first create the size of the partitions any way he/she wanted as long as they were large enough to contain the contents of the source disk's data.

6. It seems to me the preceding is a straightforward way to accomplish blackie's objective. I realize you mentioned a manual copy/paste process involving the 1 TB HDD, but it's not clear to me why this would be necessary in view that a relatively simple disk-cloning operation would accomplish a bit-for-bit transfer of data from the 1 TB drive to the destination drive. Am I missing something?

As to your question "will casper allow cloning a 2nd disk to that drive without it wiping the entire drive first?"...

Yes, Casper has the capability of cloning data to specific partitions without impacting any existing data contained in other partitions on the destination drive. So there would be no problem with Casper cloning the contents of the two separate source drives to a single properly-partitioned destination drive.

(I think I now better understand the thrust of your question and how it fits in with your suggestion involving the need for a copy/paste process.)

actually, just occurred to me, EaseUS will also clone a partition from the 2nd storage drive

tks for your response though