Hello,
I have the same problem with 2 DL380G7-machines.
They are both exactly identical, because we use Marathon High-Availibilty VM.
Transfer-rates from/to the VMs were bad and I also noticed the blinking mentioned by OP.

The first logical Drive on each server consits of 4 original HP-SAS-Drives 450GB.
Smart-Start tells me, these drives are online for 44 months, but are Ok and should NOT be replaced...but these drives are all blinking about every second.
All drives simultanously, all drives green - no amber, red or blue - just on and off and on and off...all the time.

The second logical drive on each server consits of 4 original HP-SAS-Drives 300GB.
Online for 16 months, according to Smart-Start (these have been added to the servers later - so that seems correct).
All drives good...and the LEDs of these drives are all four constant green. No blinking...just straight green (all VMs are down, so there is really no activity at the moment.)
THAT´S how it´s supposed to be, I think.

But what is wrong with the first logical drive?
I cannot find a hint, that any of its HDDs has a failure.
A controller-error? Only on Port 1 and in 2 different servers at the same time? Not very realistic...
Are the old drives somehow incompatible to the new ones?? But there are 2 independent RAIDs and they´re not mixed within a RAID.
How can that be?

So what should I do?
Replace all 8 SAS-HDDs just to "give it a try"? Quite expensive...

Any suggestions??
Please?!?!