Synology DS1821+ update HDs

[Enquiries]

I have 2 Synology DS1821+ here at home. With these Seagate SATA HDs in place:

NAS 1 : 5 x 14tb and 3 x 10tb : Total 78.2tb capacity
NAS 2 : 5 x 14tb and 2 x 24tb : Total 85.4tb capacity.

They have been working for about 1 ½ years vey well.

The 14tb drives were inside two Drobo raids, which I had to get rid of. Luckily I could reuse them in the Synology NAS.

NAS 2 is just a backup and I originally boosted the size with 2 x 24tb Seagates.

I'm thinking I could increase the size of NAS 1 by replacing 2 of the 10TB drives with 2 x 24tb, or even 2 x 30tb. Would these still work fine in the DS1821+ right now, or has Synology done something to DSM 7.2.1 to not make this happen?

Many thanks,

Keith

[ed]

Great to hear both DS1821+ systems are running smoothly, and good move reusing the Drobo drives. On your upgrade question:

The DS1821+ (2020 release) is not part of Synology’s newer 25+ series, so it does not enforce Synology-only drive compatibility. You can continue to use Seagate IronWolf, EXOS, or WD drives without DSM blocking them, even on the latest DSM 7.2.1 updates.

So yes, you can replace those 10TB drives in NAS 1 with 24TB or even 30TB models. They’ll work fine, the only thing to keep in mind is:
• Expansion behavior: If your drives are in a single RAID (SHR or RAID 6), the new larger drives will only give you extra space once enough of the smaller ones are swapped out and the rebuild completes.
• Rebuild times: On very large drives like 24–30TB, rebuilds can take much longer, so plan upgrades during lower activity periods.
• Backups: Always ensure your second NAS is fully in sync before starting a drive swap, just in case.

In short, you’re safe to add 24TB or 30TB Seagates to your DS1821+ today, DSM 7.2.1 won’t stop you.