RAID Config Question

Raid 1

Thanks, so no way around losing 50% of available storage?

Not with that drive configuration.

Two RAID 1 arrays. Like with like.

TL;DR  --> NONE

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Not sure why you need RAID in this particular setup.

If you must use RAID, you should use A single Raid 1 using just the 1 TB drives for the boot disk and the 2 TB  drives should be kept as separate, individual disks, giving you a total of 5 TB of usable space.  I wouldn't even bother making any of them RAID, with such small sizes.  I use them as separate storage and buy an inexpensive 5TB or 6 TB external disk for backup of the data.

If you were thinking you could do RAID 5, it might work with some RAID cards, but, you'd only get 3 TB of usable space out of those 4 drives with much worse performance than having 2 separate RAID 1 sets.

There's no really good reason to combine the 2TB drives into a RAID if it's for data storage.  It would be better to keep them separate and have 1 as backup if you wanted some sort of redundancy.  If you just need storage space keep them separate.  However, an external 4 TB or 5TB disk would be good to have for offline backups

i'd probably go for 2xraid 1 or possibly one raid 10

if you want more space, it is also possible to combine 2x 1T in a raid 0 and then raid 3 or raid 5 the 3x 2T
that would produce a 4Gb array instead or 3. but will be slower and more complex to handle overall

if you are lucky enough to have ZFS available, you can use a raidz with the aboove setup

other setting would include setting up a raid5 with 4x 1T and keep a separate 2x 1T mirror for faster IO. you would need to split the 2Tb into 2 1T partitions and use that for raid in order to achieve this. that would produce 3T raid 5  + 1T raid 1

you may also consider buying a couple of extra 2Tb drives and use the 1T for something else.

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note that raid setups tend to work better with identical drives since the slowest drives in term of throughput, IOps, latency, ... will slow the whole array. but they also tend to break more easily since multiple drives will likely fail in a short time frame.

Thank you Skullnobrains,

This was my initial thought also, whether the 2Tb drives can be partitioned to have 6 x "identical" drives.
On second thoughts, it will not serve a good purpose for redundancy, as when one physical drive fails, you will have two virtual drives down?

yeah. splitting the 4 drives into 6x1T and use it for raid5 or 6 is quite pointless since the failure of a ringle 2T drive will trash the array. and it will be painlessly slow.

that is why i suggested the above setups. neither will fail if a single drive fails. the first one is more performant.

that said, i would probably stick to mirrors and give up on 1T but that would depend on the needs.

a raid10 zfs would be by far the best solution if it is available to you. it is fast, forwards compatible, safe... but 3T overall.

I am using a Dell H330 RAID adapter.

Could you give me a bit more info on the DFS requirement for RAID 10 in this scenario?

i don't use DFS or know much about it or windows.

but afaik, there is no direct relation between them : DFS will run on top of the storage layer and does not need to deal directly with the disks. much less if you use hardware raid. you'll bother with DFS after your raid is configured and your server is up and running.

If you only have 2*1TB and 2*2TB the only option is 2*RAID-1
You dont have enough disks for RAID-5 (and we don't recommend RAID-5 on disks that big anyway)

Your other option is to have a single RAID 1 or no RAID.   Unless you actually have a need for specific RAID features, it's a waste of time and disk space to set up RAID.  Backups are generally more important than RAID.  RAID is a tool like a hammer where everything starts looking like a nail.

DFS is independent of RAID.  RAID volumes should just look like a larger disk.  The only affect of RAID on DFS is speed, but mainly with larger RAID sets.