WTF is wrong with my writes? (RAID 10e/Intel SASUC8I)

hardware_failure

hardware_failure

[H]ard|Gawd
Joined
Mar 21, 2008
Messages
1,370
Setup is:
Supermicro X8DTN+
Xeon E5520
Server2k3 32bit
12GB RAM (currently only 4GB available to the kernel, has to be 32 bit for a few months)
All drives are WD RE4 500GB. (WD5003ABYX)
2x on the onboard Intel ICH10R for system drives, mirrored via OS
6x in RAID 10E on the SASUC8I.

C: is the mirrored volume onboard and Z: is the 10E volume on the SASUC8I:

Crystal Disk 50MB:
ega33q.jpg

2h7gznb.jpg


Crystal Disk 1000MB:
inhlrd.jpg

1z3ckmh.jpg


ATTO:
16knnep.jpg

2ni493m.jpg


Driver:
2j0av50.jpg


Reads look I guess okay but writes just arent "write"
Anyone ever see anything like this before or have any ideas? :confused: :(
 
I appear to have something similar in my benchmarks:
http://hardforum.com/showpost.php?p=1037168670&postcount=9

However, I've moved data between the two drives in the benches and the speeds, according to WIN7's copy dialog, got up to 120-130MB/s so I don't know if it's just something with the benchmarking app or if I have a software/hardware configuration problem.
 
Here's a question: is there any data on the mirror you care about? If not, maybe you could boot from a linux live-cd and try a raw copy? e.g. something like:

create a filesystem on the mirror, mount it and do:
time dd if=/dev/zero of=/mnt/foo/testfile bs=1M count=64K
tine dd if=/mnt/foo/testfile of=/dev/null bs=1M

(where you mount the new FS on /mnt/foo - the above will write and then read back 64GB.
 
Thank you for the replies, I really do appreciate it. I think should have used different colors for the different volumes and maybe tried to be more specific...

The 2x Drives as a mirror on the onboard SATA ports (C: ) look NORMAL in the benchmarks. Theres nothing wrong there.

Its the 6x drives in RAID 10E on the SASUC8I (Z: ) that look all messed up on the write speeds. Read speeds are anywhere from 2x to 10x+ faster than writes? AND they are slower across the board from the system drives NOT stripped on the onboard SATA?

I just tried an older driver, same results :(
 
I understood about the drives. What I was getting at: if you try a different OS, that will isolate whether it is a windows driver/config issue.
 
A mirrored volume features twice the read speed of a single disk

Write speed is not improved because all copies of a mirror need updating.
 
Write speed is not improved because all copies of a mirror need updating.
Click to expand...
It should not be 38MB/s on sequential writes however. I have no good explanation.
 
Use a new gparted cd and align your partition. Win2K3 aligns to 32K - the gparted cd will align it to 1024.
 
I aligned the partition in window's diskpart with "create partition primary align=1024"

Same results. So... I gave up.

I did what I should have done from the beginning and purchased an Areca 1880i, and created a 6 drive 0+1 (RAID 10) with 2 hot spares using all 8 of the WD RE4 drives. (had some other junkers lying around for system drives)

Ho-ly-shit.

Obviously the SASUC8I nor any other simple HBA is gonna compete with that, but still doesnt explain the really bad writes.

I guess I fail at solving this one but damn is this array f'ing fast so I guess its under the bridge.

Thank you all for the replies.
 
Could it have been 10E that was the problem? 10E is always going to cause write contention issues, and write performance will depend mostly on the controller's ability to cache/re-order writes. I'd be curious about how raid 10 would perform on the same card.

Is it possible that you were creating a 1E array instead of 10E by accident?
 
thefreeaccount said:
Could it have been 10E that was the problem? 10E is always going to cause write contention issues, and write performance will depend mostly on the controller's ability to cache/re-order writes. I'd be curious about how raid 10 would perform on the same card.

Is it possible that you were creating a 1E array instead of 10E by accident?
Click to expand...
The SASUC8I is a rebadged LSI SAS3081E-R, and it uses the "LSI MPT SAS BIOS"

It has 3 options for creating RAID volumes: IM, IS, and IME. Thats it. :(

IM = RAID 1
IS = RAID 0
IME = RAID 1E/10E

According to intel, the difference between 1E and 10E is odd or even number of drives. In each case I was using an even number, so it would be 10E. IM/IME allows for hot spares. IS (RAID 0) does not allow for hot spares. (as losing any number of drives would be a complete volume failure)
 
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