Best practice for DrivePool and SnapRaid

[NicCo]

Hi,

I have 6 x 3 TB HDD. I would like to use 4 HDD to store my data with DrivePool and 2 HDD for parity with SnapRaid.

Is it possible ?

What is the best way to do that ? Add all drives into a pool or only 4 drives ?

Thank you !

[Christopher (Drashna)]

NicCo,

 

I can't give you much direction here, as I don't (won't) use SnapRAID or the like. 

 

However, this id definitely possible. We have a number of threads where users talk about this and have posted instructions/guides on how they implemented it on their system

http://community.covecube.com/index.php?/topic/52-faq-parity-and-duplication-and-drivepool/

[Cool1Net6]

Hey NicCo.

 

I have toyed with SnapRAID and other parity raid systems in the past, so maybe I can help you out. My first piece of advice is to setup SnapRAID as a Parity RAID 6. You have 6 x 3TB HDDs:

 

3TB = DrivePool

3TB = DrivePool

3TB = DrivePool

3TB = DrivePool

3TB = SnapRAID Parity P

3TB = SnapRAID Parity Q 

 

SnapRAID is able to protect against 2 drive failures (a la RAID 6) by calculating 2 individual parity drives. Since you want to use 1/3 of your space anyway to protect you data, this is the most secure way.

 

Optimizing with DrivePool: SnapRAID and other parity raid systems don't like when files change a lot on the drives. Files have to stay where they were when you made the snapshot; moving files between disks tends to 'break' the parity.

 

Anything that 'balances' files across drives should be TURNED OFF! SnapRAID will have to work harder just to maintain parity if you shuffle files around the drives too often. Setup DrivePool to balance your files when they are placed initially to keep DrivePool from having to nightly re-balance your pool. This is more efficient for both programs.

 

You can then set SnapRAID to recalculate parity after DrivePool's nightly balancer. Remember, any file that changes in your pool after your snapshot affects the effectiveness of SnapRAID to protect all files in the entire pool. 

 

Hope this helps.

[Christopher (Drashna)]

In case it helps, the "Ordered File Placement" balancer may help here. It should fill up one disk at a time, and help prevent as much "moving around". 

https://stablebit.com/DrivePool/Plugins