DrivePool and Partitions

Alex

Multiple partitions per disk

As of Build 569 StableBit DrivePool now understands that multiple partitions can exist on the same physical disk added to the pool. What this means is that if you have a 500 GB drive partitioned like this:

Volume 1 (F:\): 250 GB

Volume 2 (G:\): 250 GB

DrivePool will not consider Volume 2 as a means of ensuring redundancy for Volume 1 and vice versa. As far as folder duplication is concerned both Volumes 1 and 2 should be considered as if they are the same volume.

If you have 2 500 GB drives, and they are partitioned like this:

Disk1

Volume 1 (F:\): 250 GB

Volume 2 (G:\): 250 GB

Disk2

Volume 3 (H:\): 500 GB

Then if you create a duplicated folder and copy a file into it, that file will go onto Volumes 1 and 3 (redundancy). If you then copy another file, it will go onto Volumes 2 and 3 (redundancy).

Basically, the idea is that it shouldn't matter how your drives are partitioned, DrivePool will work with your partition structure to correctly ensure that the redundancy for files placed in folders with duplication is maintained across separate physical drives.

If you try to remove H:\ from the pool while you have a folder with duplication, you will not be able to. The system will let you know that there will not be enough physical drives left to maintain redundancy of that folder. But, if you try to remove either F:\ or G:\, then the operation will go through because removing one of those volumes will still leave the system with 2 separate physical disks. If you have more that 250 GB of files in the duplicated folder, then the operation will abort and drive removal will not continue. Even though you would still potentially have 250GB of free space on H:\, there would be no space left on one of the other drives to maintain file redundancy.

It's not important to understand the details of how this works, the point is that you can now have multiple partitions on the drives in the pool and expect folder duplication to work correctly.

Spanned volumes and anything similar

If a volume spans more than one physical disk then any other volumes on those disks (including any other spanned volumes) will not be selected as candidates for maintaining file duplication data for the spanned volume. This goes for any other non-standard partitioning scheme as well.