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Hi.
Im currently rebuilding my media server and then I stumbled over this site.
I have 1 500GB disk that is gonna be used as a system disk and 3 2TB disks for a storage pool.

My first question is about the storage pool.
My plan was to use LVM to create the pool spanning the 3 data disks, but I´ve been reading a bit about FlexiRAID and it also can create a storage pool spanning the disks (maybe with a parity disk?).
Is there a good reason to use both FlexRAID and LVM on top of that, when you get the storage pool and protection from disk failure form FlexRAID?
As I have read it, if a disk in a LVM Logical Volume Group fails, the whole group is lost. Will FlexRAID recover from that?

Hi bape and welcome to the forum. You have raised an interesting question and one I'm sure other people are thinking about too.

The reading you have done with regards a single disk failure with an LVM set up causing the whole volume to become corrupted is correct. Or more accurately, I've read the same issues too.

I've not used the pooling facility that comes with FlexRAID preferring to use symlinks to achieve the desired effect for my setup. Others have used hddfs which is a less risky option than LVM from what I've read.

Your question has been answered by the developer of FlexRAID I think and he says:

"The problem with LVM is that it will abstract the physical volume causing you to improperly define your DRU.

The key to FlexRAID is to properly defining your data risk unit (DRU).
If you end up defining a physical disk across multiple DRUs, you will end up with multiple DRU failures when that disk dies.

You might be able to get away with it if you tie each volume to a physical disk.

Although a DRU does not have to be a disk, realistically a disk is what you are trying to protect.
FlexRAID is flexible enough for you to define a DRU as anything you wish, but you should always match it with your real risk.

So yeah, you could use FlexRAID with LVM but the semantic will change greatly in what you are trying to protect."

source

Hope this helps.

Ian,