Samsung SSD PM1643 3.8TB SAS 12Gb/s MZ-ILT3T8A 2.5" @ $289.98

DouglasteR

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Dec 19, 2015
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12G Internal HD Mini-SAS SFF-8643 → (2) SFF-8680 Target-based dual port 29-pin drive receptacle

with Active/Active Round-Robin SAS Multipathing enabled. I couldn't figure out a way to make SAS wide ports work, but multipathing off a single HBA with four total drives works a treat!
Interesting, i have the same (or so i believe) cable but with 4 output ports.

Where in the MegaRAID software can i check if Multipathing and RR are active ?

I can confirm it says 12Gbps SAS but nothing else.
 

soaringswine

New Member
Nov 29, 2020
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Interesting, i have the same (or so i believe) cable but with 4 output ports.

Where in the MegaRAID software can i check if Multipathing and RR are active ?

I can confirm it says 12Gbps SAS but nothing else.
it’s only supported in HBA / IT mode on most cards but you’d see two entries per drive in the HBA BIOS and two paths per drive in your OS that supports multipath (I’m using vSphere / ESXi 6.7).

then you just change the multipath settings to have both paths be active instead of Active/Standby and use something like round robin to make use of both paths.
 
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soaringswine

New Member
Nov 29, 2020
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For reference, without dual path, my SSDs would top out at ~1000 MB/s which is the limit of SAS3 after considering 8 bit encoding.
 

soaringswine

New Member
Nov 29, 2020
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Interesting, i have the same (or so i believe) cable but with 4 output ports.

Where in the MegaRAID software can i check if Multipathing and RR are active ?

I can confirm it says 12Gbps SAS but nothing else.
four output connectors on one cable won’t allow the use of the second SSD port due to bandwidth limits unfortunately. I actually had a four connector cable and sold it and got two of the dual port cables I linked above so I could take advantage of multipathing speeds.
 

DouglasteR

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Dec 19, 2015
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Very interesting, i managed to enable MIPO on mine, but only saw a marginal upgrade (margin error) in speed.

Time to get a 12 port HBA i guess :p
 
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azev

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Jan 18, 2013
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If you have the right dual port sas cable even with 6Gbps controller you should see major improvement.
You can validate if you have the right cable by looking at the disk management; without MPIO each drive should get listed twice.
Oh and btw MPIO really only supported on windows servers, although I did found a hack to enable it on windows 10 before but I cannot find the links anymore.
 

Sogndal94

Senior IT Operations Engineer
Nov 7, 2016
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Mine is showing like this:

View attachment 19008

Should it have more than one path enable ?
Looks like 1 path to me? (as you only have one path id) =)

Can we see you MPIO config. ( i dont think this is a cable problem) It looks to me like you have set it up wrong, since we can see the device two times.

Have you done? (can i see those?)
Get-MPIOAvailableHW
Get-MPIOSetting

Enable-MSDSMAutomaticClaim -BusType "SAS"
 
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DouglasteR

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Dec 19, 2015
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Looks like 1 path to me? (as you only have one path id) =)

Can we see you MPIO config. ( i dont think this is a cable problem) It looks to me like you have set it up wrong, since we can see the device two times.

Have you done? (can i see those?)
Get-MPIOAvailableHW
Get-MPIOSetting

Enable-MSDSMAutomaticClaim -BusType "SAS"
Sure, here's the results:

PS1.PNG

if you have the correct dual port cable, more than one path should be listed, which you'd then have both set to Active/Optimized. since there's only one path listed in your screenshot, it does not look like you have the correct cable.
Yes, i believe the cable being single path is the culprit.

Guess i need a new controller first, because all my ports are populated.

Thanks guys.