The $/TiB storage cost currently creates weird choices in backup media... even making some older media formats economical again. Just finished a consumer storage option survey yesterday.
Even if you account for consumer drive+spare cost, a 8TB HDD is still the best JBOD option. For under several dozen 25GB projects, the BD-R disc drive is currently the cheapest media backup option (about 35% cheaper than HDD above 12TiB). Note 50G and 100G BD EOL media are actually equal to or a worse deal than HDD.
Also, HPE LTO9 18GB Tapes are currently around 5 to 15 times cheaper the HDD and SSD in terms of data storage cost, but the fixed cost of tape auto-loaders and drives don't always make sense until you have a significant amount of backup data. Tapes may also create a single point of failure in use... so incremental backups are a non-zero risk, and triple redundant hardware is required (old hardware gets hard to find.)
The classic joke is still true: "Fast, cheap, or good.. choose any two..."
I looked in to the bluray thing and concluded it just doesn't make sense at any level. You have to buy a bluray writer which will become increasingly rare, and then you are limited to 25GB disks where you have to factor in a chunk of that will go unused as each project won't fit on exactly 25gb.
For the effort you are expending, just getting a hard drive makes way more sense even if the $/gb is technically a little worse. The utility of hard drives is much better.
Even if you account for consumer drive+spare cost, a 8TB HDD is still the best JBOD option. For under several dozen 25GB projects, the BD-R disc drive is currently the cheapest media backup option (about 35% cheaper than HDD above 12TiB). Note 50G and 100G BD EOL media are actually equal to or a worse deal than HDD.
Also, HPE LTO9 18GB Tapes are currently around 5 to 15 times cheaper the HDD and SSD in terms of data storage cost, but the fixed cost of tape auto-loaders and drives don't always make sense until you have a significant amount of backup data. Tapes may also create a single point of failure in use... so incremental backups are a non-zero risk, and triple redundant hardware is required (old hardware gets hard to find.)
The classic joke is still true: "Fast, cheap, or good.. choose any two..."
Best of luck =3
For the effort you are expending, just getting a hard drive makes way more sense even if the $/gb is technically a little worse. The utility of hard drives is much better.