different hard drives for RAID

[ARapalo]

Currently I have a WD 1.5tb and a seagate 1.5tb. If I buy another 3tb seagate drive, can I put them in RAID 5 and have 4.5tb usable space? Basically one of the 1.5tb is used for parity/redundancy. Would it be a problem if I mixed and match different drive capacity and brands?

 

[drescherjm]

No. You will have 3TB of usable space in raid 5.

 

[hotcrandel]

Currently I have a WD 1.5tb and a seagate 1.5tb. If I buy another 3tb seagate drive, can I put them in RAID 5 and have 4.5tb usable space?

No. You would have 3TB of usable space (with 1.5TB wasted on your 3TB)

Basically one of the 1.5tb is used for parity/redundancy

It doesn't work like that. if the 3TB drive failed, you would only have 3TB of remaining space.

Would it be a problem if I mixed and match different drive capacity and brands?

In software RAID (like in Linux or FreeNAS with MADM) different brands would probably work. You might get some wonky performance.

Different sizes is less than ideal as the usable size of each array member is the size of the smallest drive.

In hardware or fakeraid, this can go from kind of a bad idea, to a very very bad idea.

Look into something like flexraid or stablebit drive pooling. RAID sucks and you shouldn't use it unless you have a specific purpose (performance or uptime) for it.