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Revodrive X2 vs (SATA SSD's in raid 0)

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December 15, 2010 8:02:53 PM

MOBO: GA-890FXA-UD7 - http://www.gigabyte.com/products/product-page.aspx?pid=...
OS: Windows 7, Ubuntu (Use both consistently but mostly worried about win 7)
Other raid: 6x 1TB HDD's in raid 5.

-Only need 60-80GB for OS's and Apps(the rest is on HDD's)

I'm leaning toward Revo due to that fact that i am using all the 6 sata III(6.0Gbs) ports for a raid 5 solution and the remaining two sata ports are a Sata II(3.0Gbs) buying a Raid controller is an option but i would prefer to not spend over $600, so my question is if i raid 0 two sata SSDs on the remaining two ports will the speed be comparable?

Other things id like to know:

If not what would be comparable?
What SSD should i go with in this situation? (realizing trim is no longer a factor as it doesn't work in raid 0 anyway)

Any other thoughts that are relevant!
December 15, 2010 11:13:06 PM

Sounds like your a "raid" enthusiast that wants SSD raid 0.
Crucial has the only Sata III SSD's out now, AFAIK, therefor, your Sata II ports would do you fine for SSD raid. I'm running Raid 0 on 2 Sata II drives thru my 890 board and all is working well. As long as your not read/writing off of the SSD's, I don't see where trim would be all that necessary.
As far as comparable speed, I believe you'll get that with a single SSD in Sata II.
If you have the time, search for Retiredchiefs input on SSD's. He has a lot of knowledge on this subject.
December 15, 2010 11:26:26 PM

i know a single SSD wouldn't match the speed of the revodrive x2 it has a 740MBs read and 690MBs write vs the Sata SSD's at around 250MBs read/write. so i gess an alternative answer is how efficant is raid 0? i doubt it maintains 100% read/write speed of each drive.
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December 16, 2010 3:28:53 AM

You are guessing right. Your Revo set-up is easily double what you could expect from SSD in Raid 0. I don't see 2 Sata III SSD's in Raid 0 beating those read speeds.
My score:
Glitch_Recursion 2
SSD drives 0
Glitch wins!
a c 126 G Storage
December 16, 2010 10:19:23 AM

Please take note that Revodrive uses Sandforce NAND controller which uses compression. The X2 with 2 controllers would have specified 550MB/s speeds; but only 200MB/s write in reality. The X4 can go up to 400MB/s of 'true' writes.

Under Windows this product degrades rapidly in performance; use either on BSD/Linux so you can have access to TRIM. I would not buy this product if you're going to use it exclusively or largely in Windows OS.
December 16, 2010 1:40:37 PM

Official specs:
http://www.ocztechnology.com/products/solid-state-drive...

It has 4 sandforce controllers and sustained write of 490MB/s (vs the 550MB/s Stated in specs)

Trim does not work in raid anyway! it is not a factor. the only reason Trim has any advantage over the OCZ garbage collection algorithms is compression which is minuscule, and not important because i will never use more that 75% of the drive space. As i stated 60-80GB on SSD everything else is on HDD's. (The smallest Revodrive X2 is 100GB)
a c 126 G Storage
December 16, 2010 4:14:20 PM

The rated specs, are:

100GB-160GB Max Performance
Read: Up to 740 MB/s
Write: Up to 690 MB/s
Sustained Write: Up to 550 MB/s
Random Write 4KB (Aligned): 100,000 IOPS

240GB-960GB Max Performance
Read: Up to 740 MB/s
Write: Up to 720 MB/s
Sustained Write: Up to 600 MB/s
Random Write 4KB (Aligned): 120,000 IOPS

The X2 gets closer to its rated specs than the original Revodrive, but it's still off; it is conducted with testing using ATTO; which writes zeroes and are easily compressible by Sandforce on-the-fly compression engine. More realistic tests conducted with CrystalDiskMark and/or AS SSD will reveal the true physical write capabilities of this SSD, which are still quite good.

Still, using 2 or 4 Sandforce SSDs on Intel controller would be faster and better, but this product could be useful to some people. Particularly those on Linux/BSD platform since, unlike Windows platform, they would have TRIM-capability while having the SSDs in a software RAID configuration. This works just fine on the Revodrive, since its a Silicon Image FakeRAID/Software RAID solution; hardware consists of 2 or 4 sandforce controllers hooked up to Silicon Image SiI-3124 PCI-X controller, hooked up to a PCI-X-to-PCI-e x4 bridge chip to make it a PCI-express card instead. Not the cleanest solution; but it works, including TRIM-on-RAID on Linux/BSD platforms. In fact, you can use my ZFSguru livecd to TRIM/secure erase your Revodrive; though it would destroy all data it would restore performance as well.

Also note that even if you keep your filesystem only 75% full, you will have written to all blocks without the SSD knowing which blocks are free, so 100% of the visible/advertized space will be in use according to the SSD if you don't have access to TRIM. Now every SSD has spare space, reserved space that the SSD uses for remapping writes. The 240GB Revodrive is actually 256GiB (not GB!) of actual physical storage, but 16GB+6.8% (conversion GB->GiB) is used as spare space; not that much since the best SSDs have 50 of 64GiB or 100 of 128GiB or 200 of 256GiB of physical space, thus alot larger portion reserved for spare space.

You can increase the spare space by never writing to a section of LBA, also known as overprovisioning. You partition 200GB of the 240GB of visible space. The 40GB will be used as extra spare space. This trick only works on a brand new SSD, or when you performed a Secure Erase. If you've already written at least once to that location, then the SSD will assume it is in use until it receives either Secure Erase or TRIM request; which may never be the case if you use it under Windows.
!