• Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
    Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.

Raid 5 performance issues on SB 950 chipset

T

Tactical

n00b
Joined
Oct 3, 2011
Messages
19
Hey guys, I'm needing some help troubleshooting a performance issue I'm having with my raid 5 setup on an AMD 950 chipset.


I've looked online and did some testing on my system, but I really think I'm running into a chipset issue (and a frustrating one at that).

I recently moved from an AMD SB 750 chipset to a 950 chipset running an Asus Sabertooth 990FX motherboard. I noticed after much frustration that if I enable raid in the bios I must install windows in a raid setup, I can't run a single boot drive in ACHI and a raid on the rest of the controllers like my SB750 chipset. VERY frustrating, and as a result I'm guessing I'm running into a chipset controller throughput issue.

Here is my setup.

Asus Sabertooth 990FX Motherboard
2x Samsung PM810 SSD's
4x Seagate 1.5TB HDD's in raid 5
8GB G-Skill memory
ATI 5850
Corsair HX 850 PSU


When I was on my SB750 chipset I never ran into throughput issues, but on the 950 I just can't get decent write speeds on the raid 5 drives. Read speed is great (300 MB/S), but write speed is just HORRID (30 MB/S).

Things I've tried to resolve the issue

1. Upgraded to the latest bios for the 990fx
2. Moved the ports around on the motherboard. Currently using ports 1 and 2 for RAID-0 and 3-6 for Raid 5 (tried 1-4 for raid 5 and 5-6 for raid 0 with no performance improvement)
3. Downgraded from a 4 HDD setup to a 3 HDD setup with the thought process that the throughput was causing the issues
4. Tried both a 64K and 128K stripe, neither drastically improved performance
5. Verified I'm using sata 6.0gb/s cables

I'm aware that my hard drives are not sata 6.0, but the write speed should never be this low

Here is my raid controller setup, if you see anything that stands out please let me know. :confused:







Raid 5 performance


Raid 0 performance




I'm just about to break down and buy a controller, I just wish I could avoid this if at all possible (never had issues with soft raid in the past and on previous controllers).

One final note... I have four new Seagate 7200rpm 3TB drives on the way from newegg, so I'm going to test this out further and see if the issue is an I/O issue on the chipset or not. I'll also be testing and seeing if Raid 10 makes any difference.

I guess what frustrates me the most is that if I enable Raid in the bios I can't install windows on a single drive, I'm almost guessing that having multiple raided devices on the same controller is screwing me up.

All I want is decent read / write speed so I can capture raw avi when gaming, or capturing for movies (pushing around 2 gb / min on average)

Thanks again in advance :p

p.s. if I need to break down and buy a decent controller, what would you suggest?
p.p.s first post... whoop!
 
1. Turn on Read Cache
2. Set write cache to Write Back.
3. Set all rebuild rates to High

Wait for the initialization / rebulid to finish before benchmarking.
 
Last edited:
Well I'm back with more information and some results for you drescherjm

1. Turned on Read Cache
2. Set write cache to Write Back like you mentioned
3. Rebuilt the states to high for you.

Once the drive was rebuilt I tested it again and I'm still getting horrible write speeds to the raid 5 array. I tested this further by breaking up my array from 4 drives to 3 drives, initialized, rebuilt, and benchmark.

I noticed that I was getting about 300 MB/S read speed (like before) but my write speed was 100 MB/S.

----------------------------------------------

I took this one step further and broke the raid up again and went over to a Raid 0 setup and found my read / write speeds were in the 400 MB/S range for read write.

Broke the array up again and went to a 4 drive setup for Raid 10. This setup was giving me about 180 MB/S (see below)



-------------------------------------------------

i'm running out of ideas as to what is causing the raid 5 setup to be so slow for write speeds, but my only guess is that I'm pushing too much I/O through the chipset controller.

I tested the J-Micro chipset which is SATA 3.0 in read / write to the array and this also was slow (bypassing the reading and writing on the same chipset).

I am running out of ideas on this one >_< My SB750 chipset gave me great speeds for read and write... I just might stick with the Raid 10 setup for now (even though it is stupid due to the double parity) very frustrating... :(

I think I'm gonna chock this one up to AMD and I/O limitations on the 950 chipset. I can't run Raid + an ACHI boot drive on the 950 chipset either (when the 750 could).

If I'm missing anything else please let me know. Please toss your .02 cents in if you have any other suggestions.
 
I noticed that I was getting about 300 MB/S read speed (like before) but my write speed was 100 MB/S.
Click to expand...

That is about all you will get out of motherboard (FakeRaid) raid5 under windows.
 
Last edited:
Yeah, are you sure you were getting more than 100MB/s writes before ? RAID5 needs XOR calculations, that has never been very fast without a dedicated controller and memory.
 
RAID5 needs XOR calculations, that has never been very fast without a dedicated controller and memory.
Click to expand...

XOR is never fast on windows without a hardware raid controller. On any other OS (for example linux) XOR calculations are fast and use a very low % cpu usage (less than 10% of a single modern core during reads and writes).

And what I mean by fast on a 3 year old core2quad at work with 9 x 2TB hitachi 7k2000s in linux software raid 6 I get > 800 MB/s reads and > 500 MB/s writes. And rebuild time is around 8.5 hours (not days like some cheap hardware raid controllers) total for the 14TB array.
 
But that's with software RAID, and I'm guessing you lose a little in security (delayed writes). fake hardware raid5 is slow, on windows or on linux.
 
To be honest I have never tried fakeraid on linux so I should not be commenting on its performance.

I'm guessing you lose a little in security (delayed writes).
Click to expand...

I think that is the big reason why FakeRaid and software raid is slow on windows. FakeRaid and windows software raid do not have an effective stripe cache which tends to cause a lot of the read - calculate parity - write back effect that kills performance. Linux keeps a cache for a few seconds which can cause data loss if you lost power (or experienced a highly unlikely kernel panic) at less than a few seconds after a write the data may have been lost. HW raid cards with a BBU eliminate this problem. Without the BBU hw raid has the same if not worse problem (that linux software raid) if you enable the Write Back cache. If you turn the cache to write through to eliminate that write performance suffers greatly.
 
You must log in or register to reply here.
Back
Top