Hi there, is it possible to have 2 1.5TB HDDs under RAID 0, then have a 3TB HDD under RAID 1 with the previously made 2 1.5TB RAID 0? (3 HDDs in total) Or would I only be able to have 2 1.5TB HDDs under RAID 0 with another 2 1.5TB RAID 0 put together under RAID 1? (4 HDDs in total) thanks
chobtime, raid 1 does not increase performance. it is for reliability. RAID0+1: needs four identical hard disk drives. RAID5: It is a RAID0 system storing parity information for better reliability. It needs at least three identical hard disk drives. On a three-drive system the total capacity will be the size of each hard disk drive times two (and not three) RAID10: It is a system using RAID0 and RAID1 at the same time. It needs four identical hard disk drives. If one of the hard disk drive fails, the system becomes a RAID1 system (mirroring). consider using the larger drive as a backup device to write to once a week or something if you want speed and dont want to try raid10.
Ok thats fair enough, if i had 4x 1.5Tbs under raid 0+1, and one was to fail, would the array revert back to being 0+1 after replacing the broken HDD?
Yes, if one drive fails in a 0+1 array, replacing it returns the array to 0+1. In fact, it is possible for two drives to fail without data loss (but not any 2 drives). READ THIS; VERY VERY IMPORTANT: If you are using any kind of onboard or "software" RAID controller, DO NOT use RAID 0, 0+1, or 5 for anything that you would mind loosing. Software RAID is notoriously buggy, and often breaks arrays. On top of that, most software and onboard RAID adapters will then attempt to repair the broken array, and doing this will often wipe the disks. The only safe onboard RAID method is RAID1, as there is no need to rebuild when the controller screws up. If you have a quality hardware RAID adapter (something with onboard RAM and a chip that gets hot in spite of having a heatsink), then RAID5 is probably your best bet...it will give you more space than RAID 1 or RAID 0+1, and it will have higher read speeds than either of those. The write speeds will be just a hair slower than RAID 0+1, but will be faster than RAID 1.
