Supermicro Backplane and LED behavior

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azev

Well-Known Member
Jan 18, 2013
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I am curious if anyone here knows the different LED behavior on supermicro chassis and backplane.
I have 2 supermicro 836 chassis both with BPN-SAS2-836EL2, one of them filled with toshiba sas nearline hard drives with Adaptec raid controller and the other are populated with HGST sas ssd with LSI 9300 hba.
The chassis filled with harddrive always have the blue drive activity on and blink when there's activity. The other chassis with SSD have a different behavior which are more expected; the LED light would only blink when there is activity. I am wondering what is causing the backplane LED to stay on even without activity on one and not on the other. I've setup many of these chassis within the past few years and never really figure it out and wonder if anyone knows what is causing these different behavior. Is it because of the controllers ?? the type of drives ? Unfortunately these are production boxes and I cannot test moving drives around or swapping controller.
 

azev

Well-Known Member
Jan 18, 2013
768
251
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So interestingly enough I am finding thing very inconsistent even compared to the finding from the post above.
Last night I installed 4 additional SSD into the chassis (different brand unfortunately) so now there are 8 drives.
The original 4 (sandisk branded SAS ssd) does not have the blue led on at all time and only blink when there's activities.
The new addition; 4 (HGST branded SAS ssd) for some weird reason the led continuously on and blink when there's activities.
I guess as long as they work who cares with how the LED works, but its just interesting how different brand SSD would have different behavior even when they all have the same interface type (sas-12g)/sas controller/backplane.
 

Aquatechie

Member
Oct 29, 2015
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I've also noticed unusual activity on my SC216BAC with the SAS3 direct attach backplane. I have 8 x HGST 7K1000 SATA drives connected to a LSI9300 HBA. All their LEDs remain off and only flash blue when there's activity. I also have 3 Samsung consumer SATA SSDs connected to the motherboard's SATA port. The UM410 and the 840 Pro behave like the HGST drives. The LED on the 850 Pro is solid blue and only blinks during activity. Go figure...
 

LunchB0xK1ller

New Member
Jul 26, 2018
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As far as I know if the drive is SAS interface the light remains on to show connectivity and flashes with activity. With a SATA interface it will only show the activity by flashing. If i am incorrect someone please correct me on this. In my 825tq backplane chassis it works like that and I only know because i have a mix of SAS and SATA drives. On certain backplanes the LEDs stay lit no matter the drive interface I believe but on most the behavior is determined by the drive being SAS or SATA.