Do more drives equal faster speed Raid 5

[thermocoffee]

Hello. I have a quick question. I'm looking to buy some Western Digital RE 2Tb drives. I can not afford to fill my 8 drive case. I was going to buy 4 of them now and buy the rest later. Once I add the other 4 drives, am I going to see a speed boost? Is there a limit of drives where there's no increase in speed?

Highpoint RocketRAID 4322
Proavio eb8ms (I know this is sata II. I want to buy sata 3 for future compatibility)

thermocoffee

 

[RealBeast]

You won't really see any significant performance difference from 4 to 8 drives, but consider leaving one as a hot spare when you get to 8 drives as the failure risk increases.

 

[popatim]

With raid 5 the more drives you have the better performance you get esp as queue depth increases. Whether you see this improvement in a 'home' setting i'm not sure but in an enterprise world where the server is getting hit pretty hard 8 drive can nearly double the thoroughput of 4.

 

[JeauxBleaux]

Highpoint RocketRAID 4322
Proavio eb8ms (I know this is sata II. I want to buy sata 3 for future compatibility)

Perhaps the pertinent point here is that the Proavio EB8MS is not compatible with High Point cards. "The ProAVIO EB8MS 24TB is compatible with ATTO R380, ATTO R680, Areca 1880X or any external miniSAS RAID controller, Highpoint controller cards are not compatible with this product." -> http://www.storagenewsletter.com/news/systems/timeline-digital-proavio-eb8ms

 

[thermocoffee]

Thanks guys! Ok I'm going to go ahead and purchase WD RE drives.

I'm using the raid for editing and VFX so speed is my friend. I need to be able to place back 2k 10bit footage.

JeauxBeaux. Very interesting! I wasn't aware of that website. I know for a fact that there are loads of people using highpoint controller cards with the proavio eb8ms. I know it's compatible.

 

[tokencode]

Go with RAID 10, it will perform far better than any RAID 5 configuration using the same number of spindles.

 

[thermocoffee]

I had no idea that RAID 10 offers good protection and it's faster than RAID 5. I will read up on it.

 

[tokencode]

RAID 10 offers as good or better protection than RAID5 and offers better performance at the cost of usable space.

 

[thermocoffee]

So why do people even use raid 5 then? I'm confused...

You lose half your storage on raid 10 no?

 

[tokencode]

RAID 5 offers a lot more usable storage, especially with larger numbers of drives. If you have 6 1TB drives for instances if you use RAID5 you'll have 5TB of storage available (N-1). If you use these same 6 drives in RAID10 you will only have 3TB of usable storage (N / 2) but it will perform far better, especially for writes.

 

[thermocoffee]

I'm mostly worried about read times. I will be working primarily with file sequences. I won't be ingesting footage from tape.

How much faster would the read times be on Raid 10?

 

[RealBeast]

For primarily read performance go with RAID 5, writes are slow but reads are very fast.

 

[tokencode]

Read performance will be about the same as a RAID10 with the same number of spindles (not drives but active spindles, 6 drives in RIAD10 is 3 spindles, 6 drives in RAID5 is 5 spindles)

 

[FireWire2]

Hello. I have a quick question. I'm looking to buy some Western Digital RE 2Tb drives. I can not afford to fill my 8 drive case. I was going to buy 4 of them now and buy the rest later. Once I add the other 4 drives, am I going to see a speed boost? Is there a limit of drives where there's no increase in speed?

Highpoint RocketRAID 4322
Proavio eb8ms (I know this is sata II. I want to buy sata 3 for future compatibility)

thermocoffee

Yes! More spindle = faster, but it is also a function of I/O processor. In your case 8x with Intel IOP348 (1.2GHz) is plenty fast for it

Recommend using Desktop Hitachi drives create a RAID5 of out of 4 drives, when you go up to 8x then migrate to RAID6
You should get about about 600MB/s both READ/WRITE in sequential, but RANDOM you may have about 200MB/s+

Get an extra HDD as inventory, if your data is important
Do not wast you money in Enterprise HDD or space in RAID10

 

[kanidrive]

Pardon the Necromancy to this old and unsolved post:

I was sniffing around the web for some specs on real world performance differences between a 3 disk RAID 5 vs a 4 disk RAID5 array. This statement was probably the best indicator of performance differences by adding the 4th disk rather than keeping it empty as a hot spare:

Read performance will be about the same as a RAID10 with the same number of spindles (not drives but active spindles, 6 drives in RIAD10 is 3 spindles, 6 drives in RAID5 is 5 spindles)

I think something that was overlooked about RAID 5, other than less loss of capacity, is while:
Advantages of RAID 1+0 = Quick recovery of data in the event of a disk failure.

Advantages of RAID 5 = Fast reads; inexpensive redundancy and fault tolerance; data can be accessed (albeit at a slower rate) even while a failed drive is in the process of being rebuilt.

So when a single disk fails in a RAID 5, its still possible to read the data (even though its MUCH slower than a 100% Healthy RAID5 Array) and keep chugging along until you can plan some downtime to swap the bad disk for a good one. Also, as the RAID5 Array is re/building, you can also use the disks (you don't have to wait until the RAID Array built is completed before you can use it after a failed disk replacement / while adding a new disk.

I'm a fan of RAID 5. More Usage of the Disks Capacity and a Performance gain with moederate-to-high durability and continuous usage.

That said, I'm not sure what OP really needs the RAID Array for, but I am struggling to imagine why the minor performance gain of a Striped RAID is ever going to be "Better" than a RAID 5 for even the most powerful of HOME PC power users (Unless you are hosting an extremely popular app/website from your home?). I've had enough downtime at the WORST POSSIBLE MOMENTS for it to happen to appreciate a solution with a viable continuous usage scenario. So RAID 10 or RAID 5 would be wise, IMO. You will have a infinitesimally marginally higher chance of data loss with "2 drives failing at once" (or before you get the bad one swapped out) but you still get a performance gain and roughly 25-33% more capacity (depending on the number of disks) than a RAID 10 if you go with a RAID 5. It's the best bang for the buck in situations like Consumer NAS Storage devices that typically only support RAID 0, 1, 5, 1+0 and JBOD.

 

[RealBeast]

Yeah, definitely a necro post, but all of your points are well made.

RAID 6 is just way too slow for home use and anyone who thinks they need it really should be looking at FreeNAS and RAIDZ or RAIDZ2, although when needed the parity data performance is slow.

I too (still 4 years later) see RAID5 as the best alternative for home users assuming that they use a hardware controller or NAS device. Motherboard RAID of any kind is totally unreliable. My preference for backup is to a second RAID5 array for cold storage, although any form of good backup is acceptable.

I will close this old thread now, as there are other newer ones on the topic.