Net Runner

Run free ESXi off a USB dongle. Would be the quickest way of getting an up and running level1 hypervisor with a nice web-based UI, small footprint and ultimately covered by various guides. Spin up a NAS virtual machine of desired flavor (TrueNAS, FreeNAS, UnRAID, OpenMediaVault, XPenlogy), pass through the existing disks into it either with RDM or the whole SATA controller (depends on your hardware). Pool your storage the way you want. Chunk a partition for NAS files. Chunk another one as iSCSI target and provide it back to ESXi for further virtual machines. Spin up any stuff you want. Bingo.

As already mentioned above, you need to expose your files over SMB for UnRAID to be able to access these files and copy them over. After this one is done you can use any Linux-based tool that can grab the files from your SMB share and put them into a folder on UnRAID. Rsync, Freefilesync, Unison - dozens of solutions will do the job. Just run them at a regular manner and it will work. Unless you have a very special and specific case that requires such kind of approach I would rather stick to some sort of backup solution like RClone or Duplicati instead of regular file-based synchronization. This way you can keep some versioning of files which might be extremely helpful. Another option that backup software can provide is a cloud tier. Cloud storage can be very cheap or even free nowadays and having another copy somewhere else is a very good option because of multiple obvious reasons. Here is a nice overview of the mentioned solutions along with some others that hopefully might be of help https://www.vmwareblog.org/single-cloud-enough-secure-backups-5-cool-cross-cloud-solutions-consider/.

What kind of data do you have on those two 8TB drives? You can theoretically try to deduplicate or compress the data on both of the drives and if you are lucky those deduplicated/compressed data may fit into one single drive. Try analyzing your existing data with this small free tool https://www.starwindsoftware.com/starwind-deduplication-analyzer and see if is doable. This way you can pack the second drive into Synology, add another two drives of the same size and create a RAID-protected array within the NAS to move the data into it. After data is inside the NAS you can add the fourth drive that was holding your data and expand your RAID array from 3 drives to 4 drives. This can be done without data loss.

It looks like some application that is running in the background is preventing Windows 10 to restart in a timely fashion. That is pretty strange since as you have mentioned previously regular shutdown goes lightning fast. Try remembering the latest software you have installed and uninstalling those applications to see if it helps. Also, try checking for Windows Updates, this might be an update that is trying to be installed during the reboot, fails and tries once again.

Have you tried using diskpart instead of Disk Management? Your USB drive probably has various partition table set-ups that the OS you are running does not support. You can try to re-format a USB key and re-partition it. Open a Command Window (cmd) Enter diskpart Enter list disk (it is important you KNOW which disk is the USB key you are formatting) Enter select disk x where x is your USB key Enter clean Enter create part primary Enter select part 1 Enter active Enter format fs=fat32 The process can take some time, but the USB should be now operational.

Can you tell a bit more about what exact phase of restart is taking that much time? Is it stuck during shutdown or boot up? Or somewhere in the middle?

Since Linux is not an option you have to stick to GUI-based Windows solutions most probably. The first one that comes to my mind is built-in storage spaces feature https://techcommunity.microsoft.com/t5/core-infrastructure-and-security/storage-spaces-how-to-configure-storage-tiers-with-windows/ba-p/256700. That will not provide caching in its common sense but speed storage-related things up since all the data will be processed through the hot tier (SSD). A great benefit of tiering is that unlike caching SSD drives will count towards your usable capacity. If your SSDs are from Intel you can use Intel CAS https://www.intel.com/content/www/us/en/software/intel-cache-acceleration-software-performance.html for free. Otherwise, there is a 120 days trial and purchasing it might be pricey. In case you need to feed this storage over LAN you can use SMB protocol that is provided by Windows out of the box (regular windows shared folders). In case SMB is not an option and block-level access is required you can use free Starwinds iSCSI target https://www.starwindsoftware.com/starwind-virtual-san-free. It is capable of utilizing RAM and SSD drives for caching too and has built-in iSCSI Accelerator to speed things up even more.

You have to share some more details and requirements with us. With a given budget, you can build a DIY NAS that will be twice as powerful and faster than any Synology/QNAP for the money. Another question is the applications and ecosystem Synology offers since their DSM is really great. But with a project like XPenology https://xpenology.org/, even this one is not a problem. Since you are building a NAS for backups, according to 3-2-1 rule https://www.vmwareblog.org/3-2-1-backup-rule-data-will-always-survive/ you will need some sort of public cloud copy some time anyways. Synology and QNAP have decent cloud-offload capabilities but still limited and sometimes vendor locked compared to complete freedom of DIY approach which is another good point to think about.

You don't get the checkbox because your File History is turned on. You need to turn it off and possibly completely disable it (bring to fresh install state) to be able to see the checkbox.

If I remember it correctly you can use different drive sizes within the same storage pool with ZFS. I would recommend installing FreeNAS and giving ZFS a try.

That is true but I would strongly recommend using some kind of a cloud tier anyways. According to the 3-2-1 rule storing all the data in one single location can not be considered as backup https://www.vmwareblog.org/3-2-1-backup-rule-data-will-always-survive/. While choosing an operating system for your NAS just make sure it has some options to upload your backups to the cloud if not right away then as a consideration for the future. Of course, these should not be the most popular and expensive clouds like Azure or AWS

It seems like a Hyper-V Manager problem. I would only recommend some obvious things like reinstalling Remote Server Administration Tools. As an alternative, you could try Windows Admin Center https://docs.microsoft.com/en-us/windows-server/manage/windows-admin-center/overview. It works via a web browser and offers similar functionality as other "thick" tools do.

The hardware is pretty decent. You can run a NAS operating system of choice off a USB drive/stick which gives you an option of using 4 hard drives since MSI A88XI has 4 x SATA ports. There are also some RAID options present on the motherboard so for the Plex server you can combine 4 drives into a RAID5. This should be enough. Why do you need an additional SATA card?

If you love your data I would recommend you going with RAID5 instead of RAID0 since in second case even slightest glitch will flush all your data away. Nowadays parity RAID5/6 are the best options for SSDs since it gives you all the benefits of using a RAID which are redundancy, performance and storage efficiency https://www.starwindsoftware.com/blog/raid-5-was-great-until-high-capacity-hdds-came-into-play-but-ssds-restored-its-former-glory-2. Just connect your SSDs to free 3GB/s ports of the motherboard, enable RAID mode and create a RAID group using the SSDs in question only. Leave the rest of the drives as is and you will be fine.

Synology has an amazing collection of applications for phones both Android and iOS which is incredibly helpful sometimes and their DSM management system is also very neat. These are some justifications of overpaying for a Synology compared to a DIY FreeNAS or whatever else built box. If these things are crucial for you and you do not want to dance around the box too much go Synology. Kinda fire-and-forget option.