Hello,

I'm building a new array from scratch and I have gone in and erase all of the disks before creating it. Is there a way to disable the 36+ hour parity check? I know that all the drives have zeroes on them, so the parity must just be zero, why do I need spending a day and a half to read 100% of an empty drive? Have I misunderstood what the Parity-Sync does?

Thanks for any tips you can provide!

-Dan Metzger

You said "erase ".

Do you mean you have run preclear on all disks?

An empty disk is not the same as a clear disk.

Not really a great idea.

Even if all your data disks are "zeroed-out", they contain a filesystem, which means, some sectors HAVE data on them.

So, the parity drive cannot be "all-zeros".

It MAY work, if all disk really only contain 0s in all sectors, but even newly shipped drives usually have undergone some tests and contain a partition table or something.

What seems to work at the beginning, maybe boomerang back lately if you try to replace a faulted drive. It can happen, that the data is restored, but the disk is "unmountable or no filesystem found" and therefor useless.

I would not take such a risk, I let it run, whatever time it takes (36hrs seem to be quite long for such small arrays ?!?!?)

Edited January 3Jan 3 by MAM59

Thanks much for those clarifications! I think I've realized what I was missing.

A formatted drive isn't really empty, it just has an empty filesystem with no known addresses pointing anywhere in the wilderness of 1s and 0s on the drive. If the Parity drive is to truly protect against hardware failure, it has to know and calculate each and every bit of every data drive. Preclearing/Initializing the drive (the feature that I thought I was looking for) would achieve that by writing 0s to every single part of the drive and then confirming them all as being zeroed, which would put more wear and tear on the drives than just mapping the unaddressed nonsense in there and achieving parity.

Have good ones!

Have you considered that you should probably run periodical parity checks so verify that all disks and their store data are readable. If you don't do this, you can find yourself in a situation where you have a known failed disk that you are trying to rebuild and then discover you have a second disk with issues that prevent the rebuild from finishing.

While very large hard drives are available today, there are penalties that must be considered in deploying them. One of them is the very long times required for any parity operation. I would imagine that 24TB drives probably require about two days (~48 hours) to perform a full parity check, rebuild of parity or rebuild of a failed data disk.