Which is faster?

[ArisVer]

A single SSD? Or a RAID 0 consisting of two normal disks spinning at 7200rpm with SATA 2?

 

[gpse]

single ssd without a doubt

 

[corkyg]

No contest - the SSD!

 

[John Connor]

I can tell you from experience using RAID 0 and then switching to a SSD that the SSD was faster. And I'm using SATA II not SATA III.

 

[ArisVer]

Thanks for the replies.

 

[Prey2big]

an SSD will absolutely murder any HDD array.

Scroll down to the absolute bottom to find "Western Digital VelociRaptor 600GB 10,000RPM SATA 3Gbps HDD"
http://www.anandtech.com/bench/SSD/83

 

[Asmith89]

SSD is always fast.

 

[ttott]

SSD for sure.

 

[lehtv]

Here's the sort of performance difference you should expect in small random reads between a good SSD and a HDD :

Small random read performance is what makes an SSD feel so responsive. RAID 0 won't make any difference to those numbers because the hard disk is limited by the seek time of the mechanical arm (~10ms delay retrieving each file).

Other tests with larger files will not show such a severe advantage for the SSD, but it will still perform much better.

 

[BrightCandle]

You need literally thousands of spinning disks to get similar random access speeds to a single ssd. Not that such an array is remotely practical of course.

An ssd is considerably faster than two HDD in everything nowadays.

 

[Essence_of_War]

In sequential reads from the outermost part of the platter (first partition), you COULD get something like 160-220 MB/s from the HDDs. A single SSD is ONLY likely to be 2-3x as fast in such a case.

In any other scenario the gap just gets wider, and often dramatically so. As others have noted, in random read/write there is just no comparison whatsoever because SSD seek time is functionally '0'.

 

[dstevod]

SSD. Full speed is higher, but it's also the responsiveness that comes from reading many small files so quickly. You'll never go back to a spinner!

S

 

[aigomorla]

SSD. Full speed is higher, but it's also the responsiveness that comes from reading many small files so quickly. You'll never go back to a spinner!

S

unless ur running a SAS R0 array with 15K spinners on a dedicated IO card.

however i doubt the op will run that... lol..

but a R0 of possibly 4 15k drives will top an IO off a single SSD.

 

[pong lenis]

I think people here mistakenly use synthetic benchmarks as proof it's faster.
Real world performance is very different from benchmarks, you won't find a significant speed difference between an SSD and RAID HDD's.

 

[dave_the_nerd]

I think people here mistakenly use synthetic benchmarks as proof it's faster.
Real world performance is very different from benchmarks, you won't find a significant speed difference between an SSD and RAID HDD's.

No. SSDs are still better. Even in the "real world".

Unless you're running some super-lightweight OS like DOS, that is so lightweight it's not I/O bottlenecked on an HD.

 

[Bill Brasky]

I think people here mistakenly use synthetic benchmarks as proof it's faster.
Real world performance is very different from benchmarks, you won't find a significant speed difference between an SSD and RAID HDD's.

"pong lenis" .....

obvious troll is obvious.

 

[BrightCandle]

In sequential reads from the outermost part of the platter (first partition), you COULD get something like 160-220 MB/s from the HDDs. A single SSD is ONLY likely to be 2-3x as fast in such a case.

I don't know of a single drive that does better than 150MB/s in any sustained transfers. They also tend to be stuck somewhere around 0.75MB/s on random reads at 4k. So when pretty much any SSD today can sustain read at 550MB/s and random read at least 20MB/s and more like 80MB/s for a decent one it means you need at least 4 drives to exceed the sustained speed and 100+ of them to get the random access. In practice it doesn't scale that well.

The trade off today at a similar price point is storage space verses speed. At the very low end pricing there are only HDDs. That is about all there is to the market now, HDDs are done from a performance perspective and ever decreasing sizes will soon solve the size problem as well.

 

[ShintaiDK]

but a R0 of possibly 4 15k drives will top an IO off a single SSD.

Nope, not even close. Also why it makes it a no brainer in DB servers to go SSD.

 

[lopyx]

unless ur running a SAS R0 array with 15K spinners on a dedicated IO card.

however i doubt the op will run that... lol..

but a R0 of possibly 4 15k drives will top an IO off a single SSD.

not by a long shot...

best case scenario, 4 15k drives get 2/3k iops

a single samsung 840 it's around 30k in the worst case scenario and around 90k iops on best case scenario :whiste:

 

[0roo0roo]

I don't know of a single drive that does better than 150MB/s in any sustained transfers. They also tend to be stuck somewhere around 0.75MB/s on random reads at 4k. So when pretty much any SSD today can sustain read at 550MB/s and random read at least 20MB/s and more like 80MB/s for a decent one it means you need at least 4 drives to exceed the sustained speed and 100+ of them to get the random access. In practice it doesn't scale that well.

The trade off today at a similar price point is storage space verses speed. At the very low end pricing there are only HDDs. That is about all there is to the market now, HDDs are done from a performance perspective and ever decreasing sizes will soon solve the size problem as well.

Maybe, maybe not, last I checked nand just doesn't shrink well. Without a break through we'll be using spinners for media storage for quite a while...

 

[tweakboy]

Bulk transfers will be twice as fast. Normal computer use, you wont notice a difference.

 

[aigomorla]

lulz... ok.. i was wrong on the SAS...

 

[glugglug]

unless ur running a SAS R0 array with 15K spinners on a dedicated IO card.

however i doubt the op will run that... lol..

but a R0 of possibly 4 15k drives will top an IO off a single SSD.

Not even close. I can verify from real-world experience that a good SSD will completely blow an array of 18 15KRPM HDDs out of the water.

Also, if you are going to go the multiple HDDs route for a non-boot drive, I think the various unraid software solutions like DrivePool will actually trounce RAID 0. But still nothing beats an SSD.

 

[0roo0roo]

Not even close. I can verify from real-world experience that a good SSD will completely blow an array of 18 15KRPM HDDs out of the water.

Also, if you are going to go the multiple HDDs route for a non-boot drive, I think the various unraid software solutions like DrivePool will actually trounce RAID 0. But still nothing beats an SSD.

The article I remember was that emc2 or whatever claimed it was 30, but that was years ago ..now its worse