Blu-ray backup for irreplaceable files: a small offline archive you can restore

Your NAS can have a very bad day. The photos, scanned paperwork and finished projects you would hate to lose deserve a copy that spends most of its life unplugged. Blu-ray makes sense for a small, deliberately chosen offline archive—not every byte in your homelab. Put the keepers on data discs, put a checksum manifest beside them, and prove you can copy them back.

Specs from ASUS and Verbatim; checksum, burning and storage instructions from the linked documentation, checked October 26, 2026.

The short answer: a desktop writer and a manageable pile of discs

Choose the ASUS BW-16D1X-U for a writer that stays at your desk. It has its own power adapter, a USB-A connection and BDXL support. Pair it with Verbatim 25GB BD-R 98397 for small batches, or 100GB M-DISC BDXL 98913 when fewer discs make the archive easier to manage.

Choose the maker-linked Verbatim 43890 for a portable alternative. Its slim enclosure and USB-powered design suit occasional laptop sessions. You give up the ASUS’s higher ordinary BD-R speed rating, but gain a writer that’s easier to pack away.

Keep your regular backups running. Optical is the “save these particular files somewhere separate” layer in a RAID, snapshots and backups plan. For frequently changing bulk data, a USB DAS backup destination is a more convenient daily companion.

Compare the writers by media, power and software

Writer and connection	Supported media, rated speeds and operating systems
ASUS BW-16D1X-U: desktop writer; USB 3.2 Gen 1 Type-A; external 12V/3A adapter.	Ordinary BD-R up to 16×; dual-layer BD-R 12×; triple-layer 8×; quad-layer 6×. Single-layer M-DISC BD-R 4×. Maker lists Windows 8/8.1/10/11 and Mac OS X 10.6+. Bundled backup/burning software is for Windows.
Verbatim 43890: portable writer; USB 3.2 Gen 1 with USB 2.0 compatibility; USB Y-cable power or external supply.	BDXL support up to 100GB, plus M-DISC. Maker rates Blu-ray writing up to 6× overall. Windows 8/10/11 and Intel Mac OS X 10.6+. Bundled Nero Burn & Archive is for Windows.

These are maker-rated maxima; the selected disc and writer determine the available burn speeds. The ASUS specification table separates read speeds from write speeds. The Verbatim product page and Verbatim-authored specification sheet describe the portable model’s media, power and software.

Don’t choose an optical writer by the USB connector alone. Match the disc format, the software you want to use and the machine that will eventually read the archive. A USB-C adapter changes the plug; it doesn’t add BDXL support.

Pick the disc size before you start sorting

25GB BD-R is the easy starting point. Verbatim’s 98397 media is ordinary write-once BD-R, supplied as a 50-disc spindle and rated up to 16×. A year of selected photos or a completed project can become a neatly named disc rather than another mystery folder.

100GB M-DISC cuts down the disc swapping. The 98913 pack contains five 100GB BDXL discs in jewel cases, with a media rating up to 6×. Your recovery reader needs BDXL support too. M-DISC is the recording technology; BDXL identifies the higher-capacity format here. Smaller M-DISC formats also exist.

Verbatim describes a “projected lifetime of several hundred years” based on ISO/IEC 16963 testing. Treat that as the maker’s projection: keep another copy, revisit the archive and migrate while you still have a working reader.

How many discs will your library need?

The calculation below uses decimal GB and a 90% target fill. The remaining 10% is our chosen planning reserve for manifests, filesystem space and awkwardly sized folders—not a measured formatting loss. The formula is round up(library GB ÷ (disc GB × 0.90)).

Disc size and target payload	120GB library / 500GB library
25GB, target 22.5GB per disc	6 / 23 discs per set
50GB, target 45GB per disc	3 / 12 discs per set
100GB, target 90GB per disc	2 / 6 discs per set

For two separately stored sets of the 120GB example, that’s 12, 6 or 4 discs, respectively. These counts assume you can divide the files into those batches. A single file larger than the target needs a different disc size or a split archive with clear reconstruction instructions. Check the burning application’s actual capacity meter before committing the batch.

If sorting hundreds of discs sounds exhausting already, use a USB4 NVMe enclosure or SATA backup dock for the larger collection. Put only the irreplaceable subset on optical.

What goes on disc?

Make a folder called archive-disc-01, then give it a payload subfolder. Choose files you can describe in a sentence:

Photo originals and their sidecars: keep edits, captions and metadata that live outside the image file.
Scans and important documents: use portable exports alongside application-specific originals where useful.
Finished projects: include source files, dependencies you can legally retain and a readable final export.
Recovery notes: explain the folder layout, required software and how to verify the files.

Leave replaceable downloads, caches and rapidly changing virtual-machine disks to your normal backup tools. Export application data into a usable form before archiving it. Copying an arbitrary live database file can leave you with something that looks complete but cannot be opened correctly.

For sensitive material, encrypt the prepared archive and keep its recovery key separately. Test decryption during the restore drill. A perfect disc with a forgotten password is an unusually shiny paperweight.

Make a checksum manifest before burning

Finish editing the batch first. Inside archive-disc-01, keep the actual files under payload, and put a short README.txt beside that directory with the disc ID, date, contents and recovery instructions.

This example uses GNU coreutils. Run it from the prepared disc folder:

cd archive-disc-01
find payload -type f -exec sha256sum {} + > SHA256SUMS
sha256sum --check SHA256SUMS

The manifest records every regular file under payload, including files in subfolders. It sits outside that directory so it won’t try to checksum itself. Freeze the batch after generating it; if you change a file, regenerate the manifest before burning.

The GNU sha256sum manual supplied by Debian documents --check: it reads the saved checksums and checks the named files. Expect an OK for each file and a successful exit status. On another operating system, use a SHA-256 tool that can create and verify a compatible manifest.

Checksums detect changed or unreadable files; they don’t repair them. Your other copy supplies the replacement bytes. Keep a copy of the manifest with your archive catalogue as well as on the disc.

Burn, verify, then restore somewhere new

Work through one disc before committing the whole collection.

Build a data-disc project. Add payload, README.txt and SHA256SUMS at its root. Use a data project rather than a playable-video project, so the files retain their normal folder structure.
Choose the writer and a supported media speed. Keep the source files local and unchanged during the burn. Stay within the application’s capacity meter.
Enable verification. For example, Express Burn’s Verify option checks data after writing; its official manual also explains drive selection and valid drive/media speeds. Let verification finish.
Eject and reinsert the disc. Copy its entire contents to an empty restore directory on separate writable storage.
Check the restored files. Run the saved manifest from the restored directory, then open several photos, documents and project files from that copy.

For a disc mounted at the illustrative path /media/ARCHIVE_01, the copy-and-check step looks like this:

mkdir -p restore-disc-01
cp -a /media/ARCHIVE_01/. restore-disc-01/
(cd restore-disc-01 && sha256sum --check SHA256SUMS)

Use a fresh restore directory for each drill. Check the copy command succeeded before running the manifest; missing files and checksum failures mean the restore needs attention. Running the check against the original preparation folder only checks the original files, so keep your terminal in the restore destination.

Label it so future-you can find it

Put the disc ID, date, format and short contents list on the case. Keep a catalogue listing which disc holds each batch, where its second copy lives and when you last restored it. Include the writer model and the software used, so the recovery process doesn’t start with detective work.

Handle discs by the edge and centre hole. Use protective cases, store them upright in a cool, relatively dry, stable environment, and keep them away from direct light; the Library of Congress care guide covers those basics. The spindle is packaging, so give archived discs individual protection.

Schedule a restore check and record its result. Read the files, verify the manifest and open representative documents. If errors appear, recover from the other copy and create a fresh archive. If finding a reader becomes the hard part, migrate before it becomes an emergency.

Start with one disc’s worth of files you cannot recreate. Burn it, restore it and make the second copy. Leave a short recovery note with both sets so someone else can follow the same steps. A small archive you can actually recover beats an ambitious pile nobody has ever opened.