SSD vs Hard Drive Raid 0

[Squirrel724]

Just a theoretical question. As striping drives together in RAID 0 increases the performance of the array, how many 7200rpm HDDs would you have to run together to equal the performance of an average 2.5in SSD? Would it actually be capable of similar speeds? Knowing that many SSDs can be bottlenecked by the performace of SATA3 can an array of HDDs actually outperform that limit?

[Oshino Shinobu]

If you add enough, then yeah, it's possible. However, the more drives you add, the smaller the increase in performance becomes with each additional drive. 

 

It's certainly not cost effective, at the least. 

[Moondrelor]

http://www.storagereview.com/ssd_vs_hdd

Scroll to the chart.

 

HDD aren't worth it anymore, only for mass storage at this point.

Though in the next couple years or so I'd say HDD will be obsolete 

[Sakkura]

HDDs in RAID0 still have far higher latency than SSDs. So you can't really match SSDs where it matters.

[Sauron]

you'd want about 5 fast hdds to match a standard sata ssd in transfer speeds. 20 to approach a pcie one

[Samfisher]

Just a theoretical question. As striping drives together in RAID 0 increases the performance of the array, how many 7200rpm HDDs would you have to run together to equal the performance of an average 2.5in SSD? Would it actually be capable of similar speeds? Knowing that many SSDs can be bottlenecked by the performace of SATA3 can an array of HDDs actually outperform that limit?

Probably infinite.  Seek and response times will not decrease the more drives you have, which is the main perception of speed when using a SSD.

[skywake]

On the more basic question of how fast the read speeds are. I had a look to try and find some benchmarks of very big RAID 0 arrays with HDDs and the only one I found was Linus' "extreme NAS" setup. He was getting ~900MB/s out of that setup. Which is pretty solid but that's less than what you can get out of some M.2 SSDs. That's before you even get to the fact that a huge RAID 0 is stupid. You're far more likely to use RAID 5 or 6 with an array that big and if you do there'll be a big write penalty. 

 

HDDs are still great for archival or mass storage of stuff where speed isn't an issue. But for everything else SSDs win out on every measure.

[scottyseng]

I would just get the SSD. The hard drives could probably match the sequential write / read of a SSD, but on random reads / writes, the SSDs just win.

 

I have six 4TB WD Reds in RAID 10 and they get 550 sequential read/write, which is similar to my Extreme Pro, but on random reads / writes, the SSD just kills the array.

[Columbo]

^{The latency of the the HDD is significantly higher than an SSD. It would take 3 really fast HDD's to equal an average SSD in performance. For fast SSD's it would take 4 or 5 drives in a non redundant RAID format. There is a benefit of burst speed on the HDD but the HDD only benefit from loading very large files, videos or game files. My 2nd tier games are in a RAID 0 and the load times in games is not much slower than those with SSD drives in games. My read speed is about 270MB on my RAID 0 but dips as low as 230MB.}