Tearing my hair out trying to install DSM

Currently reading
Tearing my hair out trying to install DSM

Operating system
  1. Windows
Mobile operating system
  1. Android
Last edited:

Took delivery of a new DS220+ today, with 2x WD Pro 20TB drives, but keep receiving error 35 when installing DSM.

Tried installing DSM on a 500GB drive which succeeds, so why can't I install it on a 20TB drive?
According to a review I read the other day at Gizarena.com...

The Synology DS220+ is powered by Intel’s latest Celeron J4025 dual-core CPU clocked at 2.0GHz with burst up to 2.9GHz. It supports 3.5-inch or 2.5-inch SATA HDD or SSD. The maximum single hard drive capacity is set for 16TB and the maximum total storage supported by DS220+ is 32TB (16TB x 2).
Carey Holzman has a video of him setting up a DS218 with 2x 20TB Segate Ironwolf drives and Rob has also made several videos saying 20TB drives are compatible with Synology NAS's

Link to Carey's video:
To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

View: https://www.youtube.com/watch?v=jr6CLuJIiSo
I realise that - but Synology has NO large HDD's on the compatibility list currently, yet they work as clearly demonstrated in the video above...
the maximum total storage supported by DS220+ is 32TB (16TB x 2)
Utter rubbish. There is no SATA3 drive size limit. Only volume limits. The DS220+ is capable of 108 TB volumes (plural). How would one do that if 16 TB drive is the largest possible?

Most website reviews are done by copy/paste drones that have near-zero NAS experience. And all these wrong-headed reviews are fodder for ChatGPT clones. What could possibly go wrong?
keep receiving error 35 when installing DSM
What drive model? Can you post screenshots of the full error message?
Had a thought which might enable me to get round this issue - could I simply install DSM on 2 4TB drives in raid 1 and then replace those with my 2 20TB drives, since DSM is installed at this point?
That should work if the 20 TB SATA drives are healthy.

Why not SHR? If you're never going to grow into a larger NAS, then RAID1 is fine... but otherwise, you are trapping yourself.
Cool - got 2 6TB drives on the way, they should be here on Saturday, so hopefully it'll install at least - probably will ultimately go with SHR1, since I can convert that to SHR2 later for more redundancy.
-- post merged: --

I know dude, but no PC to connect the disk to to test it as all laptops here and no HDD caddy's I know of currently support 20TB drives
Last edited:
probably will ultimately go with SHR1, since I can convert that to SHR2 later for more redundancy
Hold off on SHR2 until your array is >8 drives ...just sayin`
no HDD caddy's I know of currently support 20TB drives
Again, like the 'maximum drive size' for a NAS... most USB SATA3 drive docks have no limit. The so-called "up to XX TB" claims, are based on the largest drive tested at the time the unit was released. Generally there are no caps.

FWIW, my "up to 6 TB" dock handles 18 TB drives fine. It's just its darn USB2 spec that kills me on throughput. If you send me your 20 TB drive, I'll test it.
Last edited:
2x Ironwolf Pro 20TB+ in a DS720 running fine here... 7.2 beta (now) and 7.1 (prior) are both happy with them.

I upgraded from the 18TB versions (which are now in a USB3 dock, funnily enough)

Screenshot 2023-03-16 at 7.00.47 pm.png
I have a Silverstone TS231UC which houses the aformentioned 2x 18TB IronWolf Pro, a Highpoint RocketStor 6114V 4-bay unit with 4x 3TB which can do either JBOD or RAID, though I'll likely offload this soon as I have replaced this with an OWC ThunderBay 4 Mini with 4x4TB SSDs in RAID4. (SoftRAID)

And a WD MyBook Thunderbolt Duo (not USB, but I drop SATA HDDs into this and ship to a fellow Mac user for large data transfers, they also have handled all kinds of capacities - WD Red and Ironwolf).

Oh and a crummy no-name brand single bay USB2 enclosure that refuses to die, that I keep around for old devices that don't play nice with USB3.... even that has never spat the dummy at a large SATA drive.
Yay - all good with the NAS now - just waiting for the raid to finishing scrubbing, then eject one of the drives and rebuild it with the working 20TB drive - any particular order required here to de-activate the disks BTW?


Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Welcome to SynoForum.com!

SynoForum.com is an unofficial Synology forum for NAS owners and enthusiasts.

Registration is free, easy and fast!

Trending threads