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+--- Thread: SHR - if parity drive fails what happens (/showthread.php?tid=7836)
SHR - if parity drive fails what happens - Enquiries - 11-05-2022
Thank you for your youtube videos and website. I have recently brought a DS920+.
I set up the NAS with SHR as it allows for mix and match drives and easy expansion.
From watching your videos i know if a drive dies its easy to replace.
But i have a few questions i have not been able to find the answer for.
If you would be so kind to answer them for me.
If a drive dies in the NAS i know i can replace it. But while that drive is removed.
Can i still access what is on the nas? eg files, videos and so on.
Now I understand that SHR uses your largest drive as protection/parity you would call it.
But what happens if that drive dies?
Can you still access your files? Or does that mean you can not access them till you replace the drive.
Does this become a 1 point of failiure for SHR if it loses parity vs Raid which has parity
written accross all drives.
Do i need to or can i work out what drive if i have mupltiple drives of the same size
as the largest. Which drive is being used for parity and have that backed up externally or
cloned in some way to give me a drive to swap in if the parity drive was to die.
Any advice you can give on this would be great
Having originally started with standard drives i had two 6gb and two 4tb. I already shucked
two 10TB drives which will go in and replace my two 4tb drives.
Thanks for your time and help.
Regards
Chris from Australia
RE: SHR - if parity drive fails what happens - ed - 11-06-2022
Yes, this is a popular question. People wonder what happens when a drive fails.
When a drive fails, the led light will change from green to red to indicate which drive is broken. This allows you to swap it out easily. You will also see a notification in the admin panel about the failing drive.
With a broken drive, you can still access your data as if nothing happened. Sometimes you might notice slightly slower speeds because the system needs to write to fewer drives at the same time. But this might not be noticeable.
What happens if the biggest drive fails?
Usually, you would have a pair of same-capacity drives. This way if one of the biggest drives fail, the other one will ensure you can still access your data.
If you happen to add a single drive that is bigger than other drives, the system will see it as big as the other drives. So if you have 3X 4TB drives and the 4th one is 8TB drive. The biggest drive will be treated as 4TB drive. You can not fill it up beyond 4TB mark. When you add a second 8TB drive, you will gain an extra 4TB of storage space that was locked out.
You can play with this here https://www.synology.com/en-uk/support/RAID_calculator?hdds=18%20TB|10%20TB|10%20TB|10%20TB
Thank you for your support, this keeps us going.