RAID Array

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@@GJC@@

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Hi Guys,

So I currently have 2x 1TB drives in my PC and I am planning on buying another drive (probably 2TB or 3TB). Now I thought this would be a few too many drives showing up in my explorer so I want to merge or let the 2 1TB drives show up as one logical drive (that sounds quite dumb :P). Anyway as far as I have been able to find out it seems that the only way to do this is by using a RAID array.

Since its not too big of a deal if the array fails and I don't want to lose drive capacity I thought RAID 0 would probably be best, or is there a better RAID? Also is it still possible to have multiple partitions on a RAID array and can I boot from the RAID array or would that be unwise?

Another thing is I have looked at some of the RAID PCI cards and they seem quite expensive, would I need one of these or would a software RAID's performance be adequate (just has to be as fast as a normal drive?)

Also do all the drives have to be the same brand/make/model or size?
 
Keep in mind that you will have to start from scratch if you want to set up a RAID-5 array. You cannot convert your existing hard drives into a RAID array.

Software RAID works, but have a few caveats.

If using Windows, the boot disk cannot be part of the RAID array.
Linux does not have this limitation.
Software RAID also uses CPU cycles.

Hardware RAID allows you to create a single, virtual drive from three (or more) drives. This will allow Windows to boot. The upside of this is that, if you have a proper RAID controller card, it will process and handle IO operations, offloading the load on the CPU.
A cheap RAID card will most probably also utilize your CPU.

The drives need to be the same size. Brand and model does not matter. And here I assume that you will only be using SATA hard drives.

Keep in mind that RAID-0 does not have any fault-tolerance built-in. If one drive fails, you lose all your data.

RAID-1 is simple mirroring. For this you'll need two hard drives of the same size.

RAID-5 stripes your data over three (or more) hard disks. If one fails, then you can continue working without any data loss. Should more than one drive fail, you lose the array, no matter how many hard drives you've got.

RAID-6 is the same as RAID-5, but allow two hard drives to fail.

Offhand I would say that you can get away with a RAID-1 setup (mirroring) for now. Check whether your motherboard supports RAID-1. Or get a RAID card (with Windows support) which supports RAID-1. And google the card's details etc before you purchase!
 
I'd discourage you from using RAID-0 as your boot volume. All you doing is increasing the chance of failure and its a schlep restoring the OS. The key to using RAID-0, is that it should not contain critical data (ie. data you not willing to lose). You can set it up easily if your motherboard can do onboard RAID. Typically you'll be encouraged to use the same brand/make of hdd in an array but its not necessary. Size of the drives do matter (as far as I'm aware). If you have a 1TB, 2TB and 3TB hdds in RAID-0 for eg the size of the array will be 3TB. It uses the smallest hdd size, so you'll lose 1TB (on 2nd disk) and 2TB (on 3rd disk)

Or if you have windows 8 you can create a storage pool...
 
Last edited:
The_Librarian said:
Keep in mind that you will have to start from scratch if you want to set up a RAID-5 array. You cannot convert your existing hard drives into a RAID array.

Software RAID works, but have a few caveats.

If using Windows, the boot disk cannot be part of the RAID array.
Linux does not have this limitation.
Software RAID also uses CPU cycles.

Hardware RAID allows you to create a single, virtual drive from three (or more) drives. This will allow Windows to boot. The upside of this is that, if you have a proper RAID controller card, it will process and handle IO operations, offloading the load on the CPU.
A cheap RAID card will most probably also utilize your CPU.

The drives need to be the same size. Brand and model does not matter. And here I assume that you will only be using SATA hard drives.

Keep in mind that RAID-0 does not have any fault-tolerance built-in. If one drive fails, you lose all your data.

RAID-1 is simple mirroring. For this you'll need two hard drives of the same size.

RAID-5 stripes your data over three (or more) hard disks. If one fails, then you can continue working without any data loss. Should more than one drive fail, you lose the array, no matter how many hard drives you've got.

RAID-6 is the same as RAID-5, but allow two hard drives to fail.

Offhand I would say that you can get away with a RAID-1 setup (mirroring) for now. Check whether your motherboard supports RAID-1. Or get a RAID card (with Windows support) which supports RAID-1. And google the card's details etc before you purchase!
Click to expand...

Very informative. Post of the day :D
 
The_Librarian said:
Keep in mind that you will have to start from scratch if you want to set up a RAID-5 array. You cannot convert your existing hard drives into a RAID array.

Software RAID works, but have a few caveats.

If using Windows, the boot disk cannot be part of the RAID array.
Linux does not have this limitation.
Software RAID also uses CPU cycles.

Hardware RAID allows you to create a single, virtual drive from three (or more) drives. This will allow Windows to boot. The upside of this is that, if you have a proper RAID controller card, it will process and handle IO operations, offloading the load on the CPU.
A cheap RAID card will most probably also utilize your CPU.

The drives need to be the same size. Brand and model does not matter. And here I assume that you will only be using SATA hard drives.

Keep in mind that RAID-0 does not have any fault-tolerance built-in. If one drive fails, you lose all your data.

...
Click to expand...

Would using the motherboard's RAID have a noticeable effect on performance or would this be negligible? Also roughly what are the chances of a RAID 0 array failing? Would it be worthwhile to do a RAID 0 setup or should I rather leave it?

Bellerophon86 said:
I'd discourage you from using RAID-0 as your boot volume. All you doing is increasing the chance of failure and its a schlep restoring the OS. The key to using RAID-0, is that it should not contain critical data (ie. data you not willing to lose). You can set it up easily if your motherboard can do onboard RAID. Typically you'll be encouraged to use the same brand/make of hdd in an array but its not necessary. Size of the drives do matter (as far as I'm aware). If you have a 1TB, 2TB and 3TB hdds in RAID-0 for eg the size of the array will be 3TB. It uses the smallest hdd size, so you'll lose 1TB (on 2nd disk) and 2TB (on 3rd disk)

Or if you have windows 8 you can create a storage pool...
Click to expand...

Wouldn't the storage pool also have some CPU overhead? And point taken I will install the OS on another drive if I end up doing the RAID array.
 
@@GJC@@ said:
Now I thought this would be a few too many drives showing up in my explorer.

Also is it still possible to have multiple partitions
Click to expand...

If you are not doing it for redundancy but to have less drives show up in explorer, partitioning them will be, well, redundant.

If you need speed, get a ssd.
 
@@GJC@@ said:
Would using the motherboard's RAID have a noticeable effect on performance or would this be negligible? Also roughly what are the chances of a RAID 0 array failing? Would it be worthwhile to do a RAID 0 setup or should I rather leave it?
Click to expand...

Let's say that you have a 3-disk RAID0 array. Disk0 and Disk2 continues working, but Disk1 decides to go for a holiday. All your data, of course, go on holiday as well whether you want it or not.

I had a 3-disk RAID0 array set up once. One disk failed. I had major pains in bringing it up again. Luckily no data was lost.

Learnt a lesson the hard way.
 
By the by, CPU usage by software RAID is negligible - unless you run applications which uses 100% of CPU, then the software RAID will take a performance hit.
 
Ok so basically it all comes down to how much of an issue it is for me if the array fails.

Also Bellerophon86 mentioned drive pooling in windows 8, could this be used as an alternative to a RAID array? By perhaps combining different size drives into one logical drive? Or is this not possible?

Thanks for the help :)
 
I recently moved to using storage pool on Win8 in parity mode (like raid 5).
They say you can mix different sized drives but not sure how that will work. The pool is currently 4 x 2TB drives. This weekend I will be slotting in a 3TB drive to see "what happens".

I am finding the storage pool setup much easier to manage compared to standard raid 5 and ZFS.
 
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