Is there any concern with mixing drive brands and types between primary storage and parity? I have a Seagate 8TB external that I plan to shuck and use for parity and will be picking up 3-4x of the WD 8TB EasyStore (fingers crossed for red drives) that I plan to shuck and use for primary storage. I'm new to unRAID and wanted to make sure there wasn't concern mixing brands and types of drives. My reading lends me to believe I'll be fine but I hoped for some opinions before I go through setup and have to tear down if its bad juju.

 

Thanks!

No concern mixing brands, so long as the disks are good. EasyStores contain Reds, your wish should come true.

They were all Thailand sourced and the first one confirmed Red with 256MB cache. As a great bonus, you can open the cases with no visible marks or broken seals so warranty should be easy should I need it.

 

Thanks bjp999

On 7/30/2017 at 7:03 AM, porter.chris said:

Is there any concern with mixing drive brands and types between primary storage and parity? I have a Seagate 8TB external that I plan to shuck and use for parity and will be picking up 3-4x of the WD 8TB EasyStore (fingers crossed for red drives) that I plan to shuck and use for primary storage. I'm new to unRAID and wanted to make sure there wasn't concern mixing brands and types of drives. My reading lends me to believe I'll be fine but I hoped for some opinions before I go through setup and have to tear down if its bad juju.

 

Thanks!

This is also my concern if there will be problems with mixing the drive brands?

1 hour ago, kiron said:

This is also my concern if there will be problems with mixing the drive brands?

None at all. From a long term reliability standpoint I prefer a good mix, less chance of multiple drives having simultaneous issues due to poor handling during transit or other stresses.

16 hours ago, jonathanm said:

None at all. From a long term reliability standpoint I prefer a good mix, less chance of multiple drives having simultaneous issues due to poor handling during transit or other stresses.

The more I thought about this last night the more I was comfortable with splitting up my array to not be consistent. If I lose a drive, especially a parity, I hope its on a different schedule than my other drives.

 

I am also curious how sensitive is the parity "largest drive" requirement? I haven't shucked the Seagate yet so I don't know if it is 100% of the same size as the other 8TB drives. Is the requirement down to the byte or does unRAID give some leaway as long as they are very close? If I lose a few MB of storage so that the array works I'm fine with that. I'd rather answer my own question than asking here but I'm still in the first of three passes on pre-clear, almost 30h in, and I still need to do the Seagate before I'll be able to find out from the unRAID setup.

There is no leeway - the parity drive MUST not be smaller than the largest data drive.  UnRAID will tell you if you try and use a drive for parity that is not large enough. In practise it does not seem to be a problem as with modern drives the different manufacturers seem to be consistent with each other.

Edited July 31, 20178 yr by itimpi

8 minutes ago, porter.chris said:

Is the requirement down to the byte or does unRAID give some leaway as long as they are very close?

down to the byte.  Even one byte short, and unRaid won't allow the configuration (and even if it did, a single byte short in the parity drive automatically means that any rebuild is incomplete by definition)

 

3 minutes ago, porter.chris said:

If I lose a drive, especially a parity

If a drive is going to fail, you want it to be the parity drive. Parity drive contains no files, so if you lose it, you are still at fairly low risk. If you lose all parity drives and one data drive, you only lose that data drive's worth of data. If all your parity drives are intact, but you lose more data drives than you have parity drives, you lose all the data on those drives, even though parity is fine. Parity is the LEAST important drive for data recovery. High speed is good for the parity drive, because the speed of the parity drive effects all writes, but it's not involved in reads at all.

 

7 minutes ago, porter.chris said:

Is the requirement down to the byte or does unRAID give some leaway as long as they are very close?

No leeway. Parity drive must be equal to or larger than any single data drive. It's got to be that way because of how unraid parity works.

 

99% of drives are standardized to the byte, it's been that way since the 1 or 2TB came out. The only exception I've seen is a few external drives that were a little short.

Awesome responses! I'll post up my numbers once I shuck the other case and get it in the system. I'd like to get the pre-clear started on the 4th drive sooner than later. If I shutdown the box during a pre-clear cycle will it pick up where it left off or start over? What if its on pass 2 of 3, will it keep going or do I need to start that pass over again?

Shutdown the box then the preclear ends. Not restartable in place. But each cycle is separate. So if you do 3 cycles and shutdown in middle of cycle 2 then you can rerun preclear with 2 cycles to get your full 3 cycles   

I have a spare tower with hot swap bays I use for preclear using a  trial key (no drives assigned to it)