Supermicro backplane LED behaviors differ with SAS vs SATA drives

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BLinux

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Jul 7, 2016
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I came across this FAQ: FAQ Entry | Online Support | Support - Super Micro Computer, Inc.

Question
When installing either SATA or SAS hard drive into BPN-SAS-826A and BPN-SAS-846A backplane, the green/blue (activity) LED will turn on solid. However, other Supermicro backplane would show, while installing SATA hard drive LED will turn off. Is BPN-SAS-826A and BPN-SAS-846A backplane defective?
Answer
BPN-SAS-826A and BPN-SAS-846A backplanes were designed base on customer request, which blue LEDs are always ON no matter SAS or SATA drives are used when we first release these two backplane. Later on, our upper management decided that blue LED should turn on solid when SAS hard drive is installed. Blue LED will be OFF if SATA hard drive install. This would be implemented on other backplanes.
I've asked this question in the past, so I thought I'd post the info here for others. I can confirm the following from direct experience:

846A backplane: both SAS+SATA drives get a solid blue LED when present and flicker with activity

SAS2-826EL1 backplane: SAS drives get solid blue LED, SATA drives show no LED. both flicker with activity.

825TQ backplane: need to check

836TQ backplane: with SATA drives, no solid LED light, but flickers on activity. Still need to check with SAS drives.

SAS2-836EL1 backplane: with SATA drives, no solid LED light, but flickers on activity. With SAS drives, there's a solid blue LED when the drive spins up, and it flickers on activity.

826A backplane: need to check

216A backplane: I don't have any 2.5" SATA drives to try out, but my 2.5" SAS SSDs behave strangely. Currently, they don't have solid LED, but flicker with activity. however, when some of them had 520B sectors, they would light up solid blue, but were unusable by the HBA controller. Also, the LED behavior was different when using Adaptec 1000-8i HBA vs Dell H330 HBA.

I was mixing SATA and SAS drives on the 826EL1 backplane and for a moment thought my SATA drives were dead because they were the only ones not lit up. Gives me another reason to prefer the "A" backplanes...
 
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azev

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I also noticed some consumer SATA SSD does not light up any of the LED light in various backplane.
 

K D

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SAS2-826EL1 backplane: SAS drives get solid blue LED, SATA drives show no LED. both flicker with activity.
Can confirm that SATA HDDs don't light up but flicker blue with activity.

But I have a pair of intel s3500s (sata) connected to the same backplane that are solid blue when idle and blink on activity.
 

Blinky 42

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Another annoyance with SATA drives in most of the backplanes when connected to a LSI/Broadcom/Avago/whoever controller, a drive marked as a global hot spare will have a slow red light blinking which looks like the drive failed unless you look close and see the 2 blinks and 2-3x off pattern. I have fielded many calls from data center techs reporting a failed drive until they can note the stupid behavior in their notes for our racks.
 

james23

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825TQ backplane: need to check-

I can give some info on this, on my 825TQ - (the only LEDs ive seen are GREEN not blue, on this model):

--below is when disk/BP is attached to MB sata ports--
Intel DC s3610 (sata) - Green ALWAYS OFF, green flicker on Activity (but not the "real activity" flicker i see on my blue led 846A, on the 825tq its a consistent on/off type flicker, reguardless of the amount of activity)

Old Intel 520 ssd 60gb (consumer sata ssd) - Green ALWAYS ON, green flicker on Activity (same on/off type flicker, regardless of the amount or rate of activity)


--below is when disk/BP is attached to an adaptec 6805T (w the sideband / sgio connected to the BP)--
Intel DC s3610 (sata) - Green ALWAYS OFF, green flicker on Activity (same on/off type flicker, regardless of the amount or rate of activity)

(i know in the 6805T bios settings there is an option for disk activity lights, either: FAIL ONLY or POWER/ACTIVITY. (i have it set to power/activity), so it does seem the 825TQ can take its disk LED commands from the controller (if sideband is connected).

some good info:
Supermicro backplane and mysterious HDD activity leds

towards the bottom of that thread, there is some pretty interesting info in regards to LEDs and how HDDs control them via their SataPower pin11. (althought its clear from SM's reply in OP, that this can be overridden by the BP).

for what its worth, my favorite LED config, is when the LED is off, and blinks in relation to the amount of activity (and blue in color)