Intel SRT (SSD Caching) in RAID5 Array Question

[TSSPat]

Hey all! Just finishing building my HTPC.
Here are my Specs:

Case: Silverstone Grandia GD06 HTPC Case
CPU: Intel Core i5-3570K
PSU: 750W
MB: Asus MAXIMUS V GENE Z77
RAM: Corsair Vengence 16GB DDR3 1600
SSD: Samsung 840 120GB
HD: 3 x Western Digital Red 3TB
BD: LG CH12LS28


My goal is to have the 3 HDDs in a RAID5 on the Intel Chipset SATA slots along with the SSD. Obviously the OS will be on the SSD. Now I've heard plenty of good things about Intel Smart Response Technology. Is it beneficial to even do this, that way ~64GB of the SSD will be a cache for the "hot" files off of the HDDs RAID array. Or is it really just to much hassle for what it's worth.

Pro's, Cons?

Also I've read there is a very particular way of setting this up, and in some cases it actually hinders write speeds in a RAID5 array.

Any thought/info would be great!

Thanks, TSSPat.

 

[BikerEcho]

interesting thread, i will be watching over it.

I don't know what will be best for you, but here is my thoughts on it. If we say you will use 64GB of your SSD as Caching after it has been NTFS formatted you will have 47,6 GB left (93% of 120 = 111,6 - 64 = 47,6 GB)
what are you gonna do with a drive that small? use it as C:/? in that case you will have ruffly 25 GB left after windows 7 is installed.
and i don't think it's a good idea using an SSD as C:/ AND caching at the same time sense windows is already fast if it's running on an SSD, so it will only be the files from your RAID5 that will speed up.

Maybe if you use the SSD as C:/ and then only use a small portion of it as Caching, like 20GB.
then you will have ruffly 66 GB left when windows installed and a 20 GB caching drive for the RAID array.

I use my SSD as C:/ and windows is just flying.

 

[OhSnapWord]

I don't think SSD caching works with RAID.

 

[TSSPat]

I don't think SSD caching works with RAID.

I know factually that it does.
(http://download.intel.com/support/chipsets/sb/intel_smart_response_technology_user_guide.pdf)


And also I am able to allocated different amounts as far as I know, so maybe I would only use ~40Gb for caching like suggested instead.

Basically what I'm trying to get at here is that I could use the entire SSD as C:/ but then I would have parts of it storing "cold" files that I would barely access (Games, Programs, etc.)

My thinking is to make the OS on C:/ and make the max allocated space (64gb) of the SSD for caching the RAID5 HDDs that way it can cache my "hot" files automatically. That way it learns what files I use the most on my 6TB and make them read at close to SSD speeds.

Get where I'm going here?

 

[OhSnapWord]

In that case...

I would use the entire SSD as a cache drive and install the OS to the RAID array.

For what it's worth, a RAID 5 will read pretty fast, similar to RAID 0 speeds.

 

[BikerEcho]

the software to setup SSD caching limits the use to 64GB.
it's like this because intel states that it will not benefit from more space then 64GB.

RAID5's reed speed might be similar but the Write speeds are noticeable slower then RAID0.
so maybe performance here will be an issue if it's used as the OS Drive.

 

[OhSnapWord]

the software to setup SSD caching limits the use to 64GB.
it's like this because intel states that it will not benefit from more space then 64GB.

RAID5's reed speed might be similar but the Write speeds are noticeable slower then RAID0.
so maybe performance here will be an issue if it's used as the OS Drive.

Yes, RAID 5 write speed is slower than RAID 0 but still faster than a single disk.

See about getting a smaller SSD or just allocate 60GB to the OS and the remainder for the cache.

 

[BikerEcho]

Yes, RAID 5 write speed is slower than RAID 0 but still faster than a single disk.

i see. the reason i mentioned that it might be a problem as the OS Drive is because i have seen some seriously slow write speeds on a RAID5 setup. but after double checking it i can see that it should be faster then a single desk (as you stated)
i think the examples i have seen was on some bad onboard raid controllers. that will explain allot sense RAID5 requires more calculations then RAID0

 

[TSSPat]

So my idea is a solid one. The OS on the SSD with 64Gb allocated for as a cache of my most used HDD files. I think this is more beneficial do to the fact that some files on the SSD would be "cold" for sure (photoshop, games, etc.)

Ill let you guys know how the instal goes!