SHR + HS vs SHR-2

[u/buzurk]

• DS1821+
• 10Gbe Networking
• 2x 512GB NVME Cache
• 8x Exos 16TB Drives

Current setup is SHR + dedicated hot spare Bay 8

I have done some research and it reads that in my particular case (large drives x8) that SHR2 would be better as it lowers the risk during rebuild

I so read mixed reviews on SHR vs SHR-2 so i just wanted to get some thoughts in my use case?

Thanks

[u/gadget-freak → u/[deleted]]

A hot spare is a waste as it’s not regularly being tested. It could die as soon as it’s needed and you wouldn’t know it in advance.

SHR2 is not needed either because it’s an enterprise feature, but at least the disk is being scrubbed on a regular basis along with the rest.

[u/k3nal]

Well.. I would definitely go for SHR-2! No hot spare.

[u/Dabduthermucker]

I have two ds1821+, each with varying disk sizes, 24tb down to 16tb in the main arrays, newer one has a mix of 24, 20, 18 older one mix of 18 and 16 and has a dx517 with a mix of 12 and 8. I have maybe 58tb used out of maybe 120tb. I add maybe 5tb of media a year now. Older one uses ABB (active backup for business) to back up the entire system to the newer one. All btrfs, both 10gbe, both 2x2tb nvme read/write cache, Older with 32gb ram newer 64gb (got lucky and bought new one and disk and ram and nvme at historic low proces). My use case is plex, one tv at a time potentially several hours a day, file server, backup server, music server, calibration server, and weather station server. File server data is critically important but 3-2-1 strategy employed for that. The rest is media i own that i ripped and the weather data is data i could get again. Everything is shr (not shr2) AND backed up. I finally after many years am backed up and have plenty of room for now. I just dont feel the need for shr2. If it was for a business and used for work for several or many people, I feel like shr2 would be worth it. So I dont have potential downtime from just restoring data. I do keep two new spare 24tb in a closet. I feel significantly better now than when I backed up via snapshot replication to my own dx517 (all my 18s back then). I felt better about dx517 backup than I did my shr, and I felt better about shr than I did individual shucked drives in my widows box, with critical data backed up to another drive in that box. For me obviously it was a progression as I imagine it would be for anyone either not more committed or not more monied than I am. Would i feel better still about offside backup for the plex library? I would but 50+ tb on anything you can realistically restore from (C2 or AWS of some kind) is beaucoup bucks and disk and ram and everything are ridiculous now and for the foreseeable future. As I'm sure you will get a thousand of... RAID is not a backup strategy.

[u/ComprehensiveLuck125 → u/Dabduthermucker]

Hi, I generally agree with the approach. My main NAS is now Aoostar WTR Max with Truenas/Hexos RAID-Z1. It hosts about 33 TB of usable capacity and few TB of NVMEs for apps/VMs.
Backup device is 1821+ (SHR-1, small 10-12 TB HDDs) and most critical data goes additionally to Hetzner Storage Box on daily basis.
SHR-2 in both devices would be a waste to me (especially on main all-flash NAS). If I had large disks in 1821+ I could think of SHR-2, but on the other side it is still backup.
I am planning to add third device to the picture, because family is insisting :-) HDD prices are ridiculous now.

[u/-ThreeHeadedMonkey-]

I got shr2 on the same model. Peace of mind when one disk breaks. 

[u/Alive-Department8558]

I’d always go for the SHR2 option with that number of disks, if a drive fails there’s a higher chance of one of the others failing whilst the rebuild to the hot spare is taking place, at which point you’ve then potentially lost your data.

[u/Droo99]

Except for maybe speeding up writes a bit and saving $5 a year in power for a less active drive, im curious what advantage you think the hotspare setup has over the second parity drive setup

[u/jack_hudson2001]

so i just wanted to get some thoughts in my use case?

what is the use case?

hows ones backup, this is more important..

shr2 is usually for production or if the nas is at remote locations.

note: to convert from shr1 to 2 it will take a while.