Storage Solutions RAID 0+1 SSD Cache slower r/w

[aasimenator]

Hey guys,

So i have a for sale thread going on where i am selling ASRock 990FX Extreme motherboard. the plus point of having that motherboard was that it had 8 ports & all were SATA 6Gb/s so I was getting good speeds on the RAID 10 array i created using Storage Spaces in Windows Server 2012. Now that i am selling it I had to move all data to a different drive & then delete the volumes & move the hard drive to my Intel i7 2600k + Asus P8z77-V Pro motherboard.
The issue on this board is that it only has 4 Sata 6 Gb/s ports (2 intel's & 2 Asmedia) and the other 4 ports are Sata 3 Gb/s ports. So problem is that i need atleast 6 Hard drives of 2TB in Raid 1 0 + SSD for windows + SSD for Caching.

Now i cannot create RAID 10 or SSD cache for that RAID on the 3rd Party controller (ASmedia) that means that I can only use 4 hard drives & the ssd for caching & the other empty port for Windows OS.

Please take a look at the screenshots below.


1. Screenshot of Raid 10 volume + SSD 120GB + 2TB spare hard drive with no SSD for Caching

2. Screenshot of RAID 10 with SSD Caching enabled on a OCZ Agility 3 60GB SSD

3. Benchmark of Corsair Force 3 120GB SSD with Windows 8.1 on it.

My Questions:

1. Why has Write speed decrease with adding SSD caching? I've set it on Maximized mode because i have a UPS Backup.
2. I am in 2 minds about Upgrading my i7 2600k to i7 4770k on haswell as the haswell motherboards have all Sata 6GB/s ports. If i do upgrade to haswell how much of a improvement should i expect?

Hardware:
Processor: Intel i7 2600k
Motherboard: Asus P8Z77-V Pro
SSD: Corsair Force 3 120GB + OCZ Agility 3 60GB
HDD: 4 WD 2TB Greens + 1 WD 2TB Green single hard drive.
Raid: BIOS RAID 01

 

[cranky]

For a mechanical hard drive moving to 6GB/s will give you zero improvement, either a single drive or an array. Leaving aside the Asmedia, how do you have the disks connected? I hope you are aware that the WD Greens are not suited for RAID use and have a very high failure rate when used in such a way.

If you've done this right the mech drives should be on SATAII and the two SSDs on SATAIII ports. However, note that SSD caching will add to system overhead, as will software RAID on consumer chipsets. Intel's implementation of caching is a software bank that works to store your favorite apps and files, not a proper hardware look-ahead cache that I/O goes through first, as you might be expecting. Hence, it is only a marketing gimmick.

What were the speeds you were getting on the AMD rig?

 

[aasimenator]

Yes the 4 2tb WD Greens are on the Sata 2 interface with both the ssd's on Sata 3 (intel) and the spare 2tb on asmedia.

I actually never did a benchmark test on the hard drives when it was inside the AMD system. But when I was doing a hash check using ApexDC++ client I was getting 400 Mb/s read speed. When I copied files from my intel system to Amd i was getting full network throughput of 100 Mb/s (1gbps). But here within the computer itself i get around 90 mb/s from the 2tb green on asmedia sata iii interface to the Raid10 array with SSD cache enabled. & without ssd cache i get around 110 mb/s copying the same file.

I am well aware of the misconception with WD Green drives in RAID, WD Green's in Raid SHOULD NOT be used in an ENTERPRISE environment. Typically, software raid via ZFS or Windows Raid is not a problem. Also fake raid controllers (cheap ones less than 10k) with the on board intel ICH10R will also work. Specifically, its not recommended to use them in raid on a raid card that costs more then the hard drive.

If you optimize the green drives properly it should not matter. In IRST there is a option "Link Power Management" that should be disabled to prevent drives to go to sleep. If i had a full fledged raid controller I would have opted for WD SE drives but from everything that i know & understand and read on the internet WD greens are good enough for onboard (fake) raid.

 

[cranky]

No they are not You can disable sleep mode and switch off head parking, but the drive is not robust enough to handle that kind of continuous operation. Though it will work fine, you will get a higher chance of failure well before the rated MTBF. Drive actually failing or not is based on statistical probability and you are playing with that probability.

I can't understand some of the figures you are quoting. Mb/s or MB/s?

Be that as it may, your results sound a bit off (though screenshots look fine for peak array speeds, which is just a little under a single drive x 2). I have an Asrock board with B75 (almost all SATA2) and Asmedia controllers, and WD Green drives across the Intel chipset show over 120MB/s rates for large sequential file copy. Over LAN I can manage about 70-80MB/s, through a router though. Not checked the rates between controllers.

Note that different apps will show different speeds. Platter reads will always be slower than cache reads, for example. You should compare platforms across the same app, not different applications.

Good Luck.

 

[aasimenator]

^ I don't think i need to explain this but in windows when you are referring to data copy speed Mb or MB does not matter everything is read / written @ MBps. so unless this thread is in the internet section whether mb/s or MB/s it does not matter.

WD Green drives came out in 2007 & they have been used ever since for their "Green" feature in RAID Array's until RE / RED / SE drives came out recently where all of a sudden WD decided that Green drives are not meant for RAID & we all should use RED /RE /SE off course at a high premium cost. because no one bought these drives in the beginning as there was a work around to change TLER on Green, WD removed that feature in 2011.

Also with respect to MTBF, there isn't one for Green drives, I checked the specifications on the WD site, there is one for Red & RE & Black etc but not for Green Drives. I still agree with you that Green drives are not meant for RAID arrays, Windows raid, Bios raid don't count as a enterprise raid solution.

Long term storage is all about price. Since data safety should be achieved through redundancies and copies... not on MTBF or warranties. Unless WD themselves sends me a replacement for the WD Greens that i bought 1 year ago I am not going to be upgrading the Greens any time soon....

RED drives are not at all more reliable than other hard drives including WD green, infact It basically the exact same green drive with the exact same manufacturing process and same parts with extra feature of Head parking being disabled on RED's. This from a company that says that their drives are "IntelliPower" with variable speeds of 5400 rpm - 7200 rpm and just providing a drive which only works only on 5400 rpm, I think that RED drives did not need to exist if WD had the balls to just release a firmware that would enable / disable the head parking feature / TLER on the green drives to play nice in a raid environment. So yeah "WD RED for RAID" I will not be fooled by that BS marketing.

These drives are expensive, On the TE Forums itself i cannot expect to get more than 4k for the 2TB greens which is a total of 20K for the 5 drives i have where as 5 new WD 2tb RED's will cost me 35K to me its not worth the money being spent.
So I will continue to use the 2TB Green's as I see it fit for the environment I have configured for it, it has been running in RAID for over the past 1 year & all tests show the drives are healthy.

So this went off topic very quickly huh! coming back to my question which was NOT whether I should use WD Green in RAID or not but why are my write speeds with SSD cache slow? to be more specific Sequential writes. as you can see in the benchmark above I am getting 212 MB/s writes without ssd cache & when i enabled ssd caching i only get 62 MB/s is it writing to SSD first and then copying it to hard drives? I think my 60GB SSD in itself is slower here is the benchmark for it



Thank you for your response btw....i always tend to forget to thank people here[DOUBLEPOST=1385018592][/DOUBLEPOST]@cranky
ok so i am a bit confused now...

Copy from 2TB WD Green (Spare) >>>> RAID 10 Array = 80 - 110 MB/s
Copy from 2TB WD Green (Spare) >>>> Corsair Force 3 120 GB(C Drive Windows) = 90 - 110 MB/s
Copy from Corsair Force 3 120 GB >>>> RAID 10 Array = starts @ 2.1 GB/s but slows down to 230 MB/s by 90% copy.

File size 1.12 GB

 

[aasimenator]

SSD > RAID 10 ARRAY (No CACHE & WRITE-Buffer DISABLE)