I am looking for recommendations for a Raid Card that can do Raid 5 that will be detected without problems on both Windows and Linux (Mint 20). Ideally looking to stick in the $25 to $200 range. Everything I find on NewEgg seems to either be over priced or have bad reviews.
I will be using a 3 x 2TB set-up, and then, in addition, a 4 TB back-up using RSync (effectively doing a cheap version of a Raid 50).
RAID 5 or 6 adapters will be more expensive because you need one with a battery backup, or at least a capacitor storage with SSD backup for power loss.
Without a durable memory cache RAID 5 is either suicidal (lost data all over the place. invisibly.) or painfully slow.
Then if you want one that can handle an SSD array you’re paying a lot for very fast processors on the card.
I’m actually using spinning disk Western Digital drives. This is more for long term storage of documents, spreadsheets, video files, etc. I’ve been considering just going Software Raid in Linux and just not having it function when I boot into Windows. I run Linux as my main daily OS, but plan on dual-booting Windows as I’m getting into gaming and there’s those few titles where the publishers refuse to release a Linux port. I have a 1TB nvme for game storage and more frequently accessed files (that is backed up to a 1TB SSD using RSync).
I’m guessing it might be better to just get another disk, use an additional drive tray, Sata Cable, and power cable (one of the reasons I wanted Raid 5 - one fewer disc), and just go Raid 10.
The other issue is, I partially misunderstood what Raid 5 was. I though it was bit-level striping with using XOR on the bits to determine a single parity bit that was stored on the third drive.
In other words:
1 1 = 0
1 0 = 1
0 1 = 1
0 0 = 0
With the first two numbers being the data striped at the bit level across the first two drives, and the number after the equals sign being the parity bit. Now that I’ve done more research I’ve basically combined Raid 0, 2, and 4 (or 5 if you stagger the location of the bits) plus “exclusive or” into one model.
you could have a linux VM inside of a windows host - and mount the disks/partitions inside of the VM, export them through samba / virtual network to your host.
Better to think of it as creating a virtual drive that has a strange block size … that will in the background do something funny to split it up and store it across multiple drives.
So e.g. with 3 disks in raid-5 with 4k blocks … you’re building a raid-5 volume made up of 8KiB blocks.
Each 8KB block is split into 2x4KiB data blocks and 1x4KiB parity block (xor of the previous 2).
Each such triplet is then rotated around the 3 disks as it’s stored.
In this simplest/purest raid-5 as I described above … there’s lots of problems with how you handle “corruption” and “power loss” and that kind of stuff, the only real problem solved is a total failure of a single drive.
So, you might as well run raid-0 across 3 drives + additional backup drive. (it’s almost as safe, but much faster for your day to day stuff).
Also, welcome!
First I wanted to point out that you could also look into ZFS as a filesystem. This would make your need for a raid controller obsolete. I only use ZFS under Linux but I think I have heard that I works under Windows as well. ZFS is a rabbit hole on it’s own, but it is also worth all the effort in my opinion.
If you really are set on buying a raid controller I can recommend buying a used one like an IBM ServeRAID M5014 with an attached battery. This controller can handle up to 8 drives in raid5 or given you get a card with the so called ‘advanced feature key’ also raid6 and many other raid combinations.
Finally I wanted to advise you to read up on the differences between raid5 and raid6. I have used raid5 for quite some time myself but with the size of modern drives it is quite a risc that if something goes wrong all your data on the array might be lost due to a combination of an error on the disc in combination with a read error of one of the drives of the raid array, If you want to put something on the discs that is important I would advise you to use raid6 instead.
P.S. I wanted to point out that you remember raid is no replacement for a proper backup of all important data.
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