RAID 0+1

[pokeyoats]

Hello all,

I've just had another RAID 0 array die and I've kind of had enough. I'm lazy and I don't backup my Data enough. So, I want to go RAID 0+1

I currently have a 750GB MomentusXT 750GB Hybrid drive, and here is my (I hope) cunning plan.

I want to get another MomentusXT 750GB and 2 Non Hybrid 750GB drives (for a cheaper price). My understanding of 0+1 is that the first 2 drives are a RAID 0 conf and they are Mirrored to another 2 drives that are RAID 0.

Thus, my question is, can I put the two MomentusXT Hybrid Drives together as a pair and use two other brand (Non SSD Hybrid drives) as the mirror in the RAID 0+1 configuration.

My goal would be the Hybrid SSD performance of the first pair mirrored to the non Hybrid SSD second pair.

If it helps, here is how I am hoping to build the array.

Drive 1: MomentusXT Hybrid SSD 750GB
Drive 2: MomentusXT Hybrid SSD 750GB
Drive 3: Seagate Barracuda ST3750525AS 750GB
Drive 4: Seagate Barracuda ST3750525AS 750GB

Would this work and would I get the performance benefits of Hybrid SSD from the first pair?

Thank you kindly.

 

[blazorthon]

I think that it would work, but I'm not an expert on storage. I can say that it would probably not write to the hybrid drives any faster than the mirrored drives, but it might read faster than regular drives would (for data stored in the hybrid drive's cache).

 

[pokeyoats]

This gives me a lot of hope. I am definitely happy to sacrifice write speed for an increase in read performance because that would be the predominant increase I'd be looking for.

 

[pokeyoats]

This double posted somehow...

 

[blazorthon]

You're welcome. Sorry an expert didn't give you more credible information than I can.

 

[Jim_L9]

I agree that the write performance would be that of the non-hybrid drives, but read speeds should be that of the hybrid drives. To verify that check with the manufacturer of the RAID controller. I am assuming your MB doesn't support RAID 0+1 and you will need an appropriate RAID controller.

 

[Kursun]

You probably do know that raid 1 is not a substitute for backups.

I didn't try the configuration you plan to do but I had raid 1 setups and I decided it produces more problems than it solves. At the slightest problem the raid 1 pairs loose their synchronization and it takes many hours to "build" themselves.

 

[blazorthon]

You probably do know that raid 1 is not a substitute for backups.

I didn't try the configuration you plan to do but I had raid 1 setups and I decided it produces more problems than it solves. At the slightest problem the raid 1 pairs loose their synchronization and it takes many hours to "build" themselves.

It's not a good substitute for regular backups, but it is supplementary. It's a real-time backup and that's important for keeping data that is written to the drive before the next backup because if the drive fails before the next backup, then data written after the last backup would be lost. This also allows you to have spare drives should one of your drives fail. Besides, there shouldn't be problems that cause them to need to re-build themselves.

 

[blazorthon]

I agree that the write performance would be that of the non-hybrid drives, but read speeds should be that of the hybrid drives. To verify that check with the manufacturer of the RAID controller. I am assuming your MB doesn't support RAID 0+1 and you will need an appropriate RAID controller.

I think that a lot of Intel motherboards support RAID 0+1, but only with SATA2 drives.

 

[foscooter]

No, all the drives need to be the same.

You wil be limited the array to the smallest and slowest drive.

Now, you want all 750GB sizes, good.

But are far a put the RAID 0 on the hybrids, and the RAID 1 on the non-hybrids, I don't think that will work.

RAID 1 mirrors the drive, so everything is copied in real time to each drive, so the slowest drive will be the limiting factor.

Are hybrids really worth it? I think you'd be wasting your money on hybrids HDD in RAID 0. You shouldn;t need to RAID 0 a hybrid anyways.

With RAID 0, any good (preferred RE rated) HDD should do. I've RAID 0 2xSamsung Spinpoint F3 1TB drives with good results.

Maybe you should look into RAID 5: RAID - Wikipedia

I always advise against any RAID as a back up, but you already understand that.

 

[pokeyoats]

My Motherboard (nforce 570) supports RAID 0+1 so I'm right there.

Can anyone possibly tell me how the mirroring works in a 0+1 config?

Is the first pair mirrored? i.e. Drive 1 -> Drive 3 & Drive 2 -> Drive 4.

Would I set the drives up in the example in my first post or is it a situation where it might be:

Drive 1: Hybrid SSD
Drive 2: Barracuda
Drive 3: Hybrid SSD
Drive 4: Barracuda

And I understand that it's not a substitute for backups but I would like the speed increase of RAID 0 with some redundancy, because as I said I have lost a 0 array twice now.

 

[pokeyoats]

I have no idea why it keeps double posting...

 

[blazorthon]

No, all the drives need to be the same.

You wil be limited the array to the smallest and slowest drive.

Now, you want all 750GB sizes, good.

But are far a put the RAID 0 on the hybrids, and the RAID 1 on the non-hybrids, I don't think that will work.

RAID 1 mirrors the drive, so everything is copied in real time to each drive, so the slowest drive will be the limiting factor.

Are hybrids really worth it? I think you'd be wasting your money on hybrid HDD in RAID 0.

With RAID 0, any good (preferred RE rated) HDD should do. I've RAID 0 2xSamsung Spinpoint F3 1TB drives with good results.

You would be limited for writes, but if you read the hybrid drives and they simply copy mirror data on the other drives, then you should benefit from the extra read speed that the hybrid drives' caches offer. Also, yes, hybrid drives really are worth it. Copying should mean that only write speeds are limited to the slowest drives, not read speeds. Considering that the hybrid drives shouldn't write data any faster than regular hard drives anyway, that's not really a loss.

 

[blazorthon]

My Motherboard (nforce 570) supports RAID 0+1 so I'm right there.

Can anyone possibly tell me how the mirroring works in a 0+1 config?

Is the first pair mirrored? i.e. Drive 1 -> Drive 3 & Drive 2 -> Drive 4.

Would I set the drives up in the example in my first post or is it a situation where it might be:

Drive 1: Hybrid SSD
Drive 2: Barracuda
Drive 3: Hybrid SSD
Drive 4: Barracuda

And I understand that it's not a substitute for backups but I would like the speed increase of RAID 0 with some redundancy, because as I said I have lost a 0 array twice now.

Hybrid 1 + Hybrid 2 in RAID 0
This striped array is in RAID 1 with this striped array:
Barracuda 1 + Barracuda 2 in RAID 0

I assume that it would have the hybrids as drives 1 and 2 and the Barracudas as drives 3 and 4.

So, you'd probably need to set up the RAID 0 arrays and then set the two RAID 0 striped arrays into a RAID 1 mirrored array with the hybrid drives as the primary set.

 

[foscooter]

Great info blazorthon! I did not know that about hybrids. I have SSDs.

 

[blazorthon]

Great info blazorthon! I did not know that about hybrids. I have SSDs.

http://www.tomshardware.com/reviews/hybrid-hard-drive-flash-ssd,3116-10.html

We found that PCMark 7 storage performance typically doubles when compared to conventional 2.5” hard drives after a few repetitions of the workload.

Hybrids provide a decent read performance niche between huge cost per GB, but very fast SSDs and minimal cost per GB, but much slower hard drives.

 

[pokeyoats]

Thank you so much blazorthon - I'm going to order my drives and get building!!

 

[pokeyoats]

I swear the double posting is not my fault - every time I hit submit it says the site is temporarily down and then I come back to the thread and there's a double post.

I've changed from Chrome to IE to see if it was a browser problem, it's not, it's following me!!

 

[blazorthon]

I swear the double posting is not my fault - every time I hit submit it says the site is temporarily down and then I come back to the thread and there's a double post.

I've changed from Chrome to IE to see if it was a browser problem, it's not, it's following me!!

Tom's is one of the buggiest sites on the web. This is proven time and time again

Try Firefox. It likes Tom's more than most browsers and if you play with a few settings, it's pretty much as stable as a browser can get. Chrome and IE have occasional problems, especially with Tom's sites. I don't think that they are as tolerant of buggy sites as Firefox. At least you're not using Opera because Opera hardly even works with Tom's at all.

EDIT: I just had the same problem that you're having and it happened in Firefox (Technically, I use Pale Moon, which is based on FF). What I did to solve it was hit the back button and reload the page, that way it didn't double post. It happened once and not again after that.