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smcpartlin

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Best raid controller for SSD drives.

Advice on SSD drive options and RAID controller for windows 7 x64
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arnold
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Usually one buys the car and then decides which tires are best.
SSD is just a storage medium (an expensive one).

Which RAID setup are you looking to configure?
RAID 1, RAID 5,6,10? Or RAID 0

3ware have good SATA raid controllers (hardware controller on the card versus software relying on your processor for RAID functionality which is what many built-in motherboard SATA raid controllers do.)

The RAID type you want, would help narrow down your search



SSD requires special consideration for a RAID controller.  First, you have to make sure the controller actually works with your specific make/model.  As such I am not going to blindly tell you what works, since even compatibility can depend on specific firmware revisions and operating systems.   So for compatibility, check with BOTH the SSD & controller vendor.

Having said that, I want to discourage you first.  If you are buying a SSD for speed, then you better think carefully.  It will cost you more for the RAID controller that won't have a significant performance penalty then what you paid for the SSD.  You also better have PCIe 2.0 motherboard, unless you just have 2 SSDs.  

If you want RAID1, RAID0, then use native windows software-RAID, this will be fastest.  If your O/S supports RAID10 natively, then use software RAID on that as well.  

Only situation where I see RAID + SSD on a Win7 that makes at least a little sense is RAID5, and if you are doing RAID5, you better sharpen your pencil and run benchmarks & compare pricing.  You are borderline where it will cost you more money for an appropriate controller that can handle the performance then if you just bought bigger SSDs and went RAID1.


The latest LSI MegaRAID 9265-8i would be my current choice...but it is still to be delivered to the major resellers...

Regarding performance, no doubt that the 60000 IOPS/500MB per SSD sustained by SandForce 2000 series based controllers would outclass any 15Krpm drive (and their 400 IOPS/160MB limits) even if the real gap is IOPS based performance.

I would:
-Go RAID 10 (on a basic SATA card) if you can afford the extra cost
-Go RAID 5/50 on a high end controller with a battery backed large write cache
And check if the RAID-card you are willing to buy supports the TRIM-feature, as well as your SSD's. Otherwise you will see the performance degrade over time.
Once again, TRIM is NOT a mandatory feature and is a useless feature when:
the same sectors are rewritten and rewritten again (DBMS usage for Data/Index/Some Logs/Most Temps)
there are more than 20GB left available on the SSD (Most SSD offers 100/200GB using 128/256GB of raw NAND flash space)
parity RAID arrays are defined because the parity stripe evaluation disallow any sector based TRIM by design
BigSchmuh:
As the threadstarter will be using Win7 x64, I guess point 1 is unlikely. Point 3 is very relevant however.

Can you provide some more information on your second point? I thought TRIM would inform the SSD which sectors can be safely overwritten/zero'ed out. Even if there"s >20GB space left, that space can be in address blocks which once contained valid data and haven't been "trimmed", and you would still see performance degradation, no?
1/ Many usages are this "rewritten sectors" kind of...just think of the swap file for example.

2/ No. TRIMming sectors just allow the garbage collector (GC) to recycle them earlier. Without TRIM, the GC still has a lot of free space that are useable only by the internal SSD which means the performance are very stable.
==> At early age of SSD, manufacturers were marketing the FULL "NAND GB" space at the cost of a high performance degradation when sustaining a long random write workload ==> This is the past.

3/ A parity raid array is defined using a stripe size which means all involved drives in the array is storing this stripe size as a minimum bucket.
If your OS is sending a TRIM command to some deleted sectors (Ex: 16 sectors/8KB TRIMed on a 64KB r5 array with 6 drives), the raid controller need to store a parity block of the stripe size with some sectors clearly used and some others marked for RESET (=TRIMed).
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smcpartlin

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Our current app is for hd video editing and rendering of finished video.  I have fusion io cards but they are not very big for the money.  So we are going to use that cars/drive for temp files and Pre rendered info.

Source videos will be on sas 15k drives (2x450g) raid 0 and the target would be the disks in question.  Machine has xeon CPUs and 12gb + of ram.

I would like to know more about the lsi 9265. I'll order one from CDW in the morn.  Now I got to look at drives.
Our current app is for hd video editing and rendering of finished video.  I have fusion io cards but they are not very big for the money.  So we are going to use that cars/drive for temp files and Pre rendered info.

Source videos will be on sas 15k drives (2x450g) raid 0 and the target would be the disks in question.  Machine has xeon CPUs and 12gb + of ram.

I would like to know more about the lsi 9265. I'll order one from CDW in the morn.  Now I got to look at drives.
The LSI MegaRaid 9265-8i should support up to 8x of the latest (SandForce 2000 series based) SSD
...but this is clearly outperforming your needs and the product looks like being at early stage of  reseller delivery.

With 2x SAS (Seagate Cheetah 15K7 ?) drives in RAID 0, you may expect between 340 and 400MB/s of sustained sequential read throughput. That is for your input video.

To my opinion, regarding your "video editing workstation" usage, I would :
-Have OS/Apps on SSD
-Have no Swap or Swap in a small RamDrive (like RamDisk )
-Consider Temp files in a RamDrive (this is possible if the temp space can stay below few GB) otherwise SSD
-Have your video data on large "Enterprise class" SATA drives (like Seagate Constellation ES 1TB for $130) in RAID 10 (=4TB for $1040) arrays (SSD are not worthing the price gap against HDD when sequential usage are needed)
Agreed, SSD is unnecessary.  You will spend LESS money and have better performance by picking up some constellations, but if budget allows, you will be MUCH better off with a pair of the 15K.7 SAS-2 drives.  These drives can be configured to perform much better with video streaming, and will have profoundly fewer errors.  

Read the specs and stuff on the ST3600057SS
Constellation ES : Unreadable sector per bits read : 1 per 10^15 & Annualized Failure Rate 0.73%
==> 1TB for $130
Cheetah 15K7 : Unreadable sector per bits read : 1 per 10^16 & AFR 0.55%
==> 600GB for $464 (6x more expensive per GB)

Using RAID 10 (and hotspare) would allow you to go SATA (Enterprise class drives usually has a 1 per 10^15 UBE ... but keep away from "Desktop/Consumer class" and its 1 per 10^14 UBE) and have more performance and space available while keeping reliability risk at a very low level
OK I get it that the Cheetah's are more expensive... but they are more reliable, What would the iops be with the Constellation's?

I can tell you that the FusionIO card has iops way over and above anything, but it's stupid expensive and small in size. I am using that for temp files for the video editing software. (helps in rendering)

I think the 2 SAS 450g's are fine for now... but will look at either the Constellation or the Chheetah for disk.,
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BigSchmuh
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But IOPs are irrelevant in video streaming, it is all about throughput and from a technical perspective, pre-fetching against queued I/O list if it is a mechanical drive.  This is not the right type of application that warrants a SSD.
Still not sure my question was really answered.