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Slow speeds on SSD Raid 0

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pianoman88

macrumors regular
Original poster
Aug 20, 2010
216
57
I installed a Samsung 840 Pro on my 2012 Mac Mini server and was so impressed with the speed that I replaced the two smaller SSDs (Raid 0) in my LaCie Little Big Disk (connected using Thunderbolt) with 840 Pros as well.

I installed Black magic design's Disk Speed Test and expected to see high from the array. What I saw was just the opposite.

I use Trim Enabler on all of the drives.

There is 281.13 Gb of space remaining out of 1 TB.

Any suggestions as to the cause?
(I'm including a test of the Mac Mini's drive as a reference.)
 

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hfg

hfg

macrumors 68040
Dec 1, 2006
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Cedar Rapids, IA. USA
If you used a older hard disk LaCie Little Big Disk TB enclosure for your SSD RAID-0, you may actually have SATA II inside, and the firmware is optimized for hard disk usage which slows it down.

However, your speeds do seem abnormally slow even with this consideration. Here is a DiskSpeedTest of one of my "old" LittleBigDisk TB enclosures with a pair of SSDs (I think Crucial M4) in RAID-0:

(Using 840 Pro SSDs should produce about the same read speeds, but with higher write speeds close to the read speed.)
 

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P

pianoman88

macrumors regular
Original poster
Aug 20, 2010
216
57
hfg said:
If you used a older hard disk LaCie Little Big Disk TB enclosure for your SSD RAID-0, you may actually have SATA II inside, and the firmware is optimized for hard disk usage which slows it down.
Click to expand...

It shipped with two SSDs.
 
AFEPPL

AFEPPL

macrumors 68030
Sep 30, 2014
2,644
1,571
England
Agree with above - it's more than likely a SATA II interface, so at theoretical best you could get 300MB/s, so those results look about right.
 
P

pianoman88

macrumors regular
Original poster
Aug 20, 2010
216
57
hfg said:
Was that an LaCie oem SSD product, or somebody modified one?

If it is the newer black LaCie LBD TB2 with 1TB in RAID-0 SSDs, it should be blazingly fast ... something is wrong!
Click to expand...

It was their first version. It was on sale - cheap - at Best Buy. Now I know why.

I guess that it's time to invest in one of OWCs Thunderbay cases.
 
Celerondon

Celerondon

macrumors 6502a
Oct 17, 2013
683
125
Southern Cal
2010 Mac mini = USB 2.0

westentertainer said:
this it what im getting with a crucial sad in a inatec ex caddy rubish isnt it what could be wrong? 51 write 54 read
Click to expand...

In this thread from February westentertainer had a similar problem.
westentertainer said:
can’t get air drop to work
hi can’t seem to get air drop to work beetween my mini 2010 with yosemite to join my iPhone 6 plus ...
Click to expand...


yjchua95 said:
Both the caddy and the Mac itself must have USB 3.

Only Macs from mid-2012 and later (Ivy Bridge and later) have USB 3.

The caddy itself must also be USB 3.
Click to expand...

Is this slow performance with that same 2010 Mac mini?
 
Y

yjchua95

macrumors 604
Apr 23, 2011
6,725
233
GVA, KUL, MEL (current), ZQN
Celerondon said:
In this thread from February westentertainer had a similar problem.





Is this slow performance with that same 2010 Mac mini?
Click to expand...

The Mac Mini 2010 does not have USB 3, so yes, the performance is slow and normal.

----------
westentertainer said:
So I would be better off inserting into the mac making it internal
Click to expand...

Exactly, because your Mac Mini does not have USB 3.0 ports.

Even internally, expect around 300 MB/s or so, because your internal bus is a SATA2 bus. Only 2011 models and later have SATA3.
 
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