Confused about SFF-8643 to 4 x SATA breakout cables : forward, reverse, straight , crossover etc.

Lance Longreen

New Member
Sep 10, 2019
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0
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So bought the Silverstone CS381 (which also Servethehome featured a while ago)

SilverStone CS381 INTRODUCTION

https://www.servethehome.com/silverstone-cs381-review/

This NAS box has 8 drives and they are connected 4 and 4 to 2 cage/back-planes.

Now i apparently got the wrong SFF-8643 to 4 x SATA breakout cables as the drives are not detected and they dont spin up.

Now i researched a bit and see there is forward, and reverse and straight and crossover types of this cable.

It seems the more i read results on this from google there more unclear it becomes.

1) I see Silverstone them self has the cable but its not in stock anywhere at all in Europe and I am not paying another 180 USD for 2 cables when the box already costs 370 plus USD (tax and import toll to Europe from the US) SilverStone CPS05-RE INTRODUCTION

2) So are there 4 versions of this cable so reverse and forward (straight versions) and then both also exists in cross over versions ? or are there only 2 kind of cables so forward and reverse and the word "crossover" that some resellers use is the same as reverse ?

Really confused about all the forum posts i found about this where it seams everyone is in fact mixing up the terminology or them self not understanding it properly.

Really appreciate to get this cleared up by someone that actually understands it and can explain it clearly.

Thank You
 

BlueFox

Well-Known Member
Oct 26, 2015
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476
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I've not seen the word "crossover" used when it comes to SFF cables before. I thought there were only two types. You presumably got forward cables (the more common type) and need reverse ones.

Forward = HBA has SFF connectors
Reverse = drive backplane has SFF connectors
 
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Lance Longreen

New Member
Sep 10, 2019
5
0
1
I've not seen the word "crossover" used when it comes to SFF cables before. I thought there were only two types. You presumably got forward cables (the more common type) and need reverse ones.

Forward = HBA has SFF connectors
Reverse = drive backplane has SFF connectors
If you look in many manufacturers web pages it seems there is 4 types and several of them use the word crossover.
 

Sleyk

Well-Known Member
Mar 25, 2016
1,023
407
83
Stamford, CT
So bought the Silverstone CS381 (which also Servethehome featured a while ago)

SilverStone CS381 INTRODUCTION

https://www.servethehome.com/silverstone-cs381-review/

This NAS box has 8 drives and they are connected 4 and 4 to 2 cage/back-planes.

Now i apparently got the wrong SFF-8643 to 4 x SATA breakout cables as the drives are not detected and they dont spin up.

Now i researched a bit and see there is forward, and reverse and straight and crossover types of this cable.

It seems the more i read results on this from google there more unclear it becomes.

1) I see Silverstone them self has the cable but its not in stock anywhere at all in Europe and I am not paying another 180 USD for 2 cables when the box already costs 370 plus USD (tax and import toll to Europe from the US) SilverStone CPS05-RE INTRODUCTION

2) So are there 4 versions of this cable so reverse and forward (straight versions) and then both also exists in cross over versions ? or are there only 2 kind of cables so forward and reverse and the word "crossover" that some resellers use is the same as reverse ?

Really confused about all the forum posts i found about this where it seams everyone is in fact mixing up the terminology or them self not understanding it properly.

Really appreciate to get this cleared up by someone that actually understands it and can explain it clearly.

Thank You
Alright:

There are usually only 2 types of SAS cable to deal with, a 3rd if the manufacturer knows what theyre doing.

1. Host to Target (Forward Breakout)
2. Target to Host (Reverse Breakout)
3. Crossover (In a sense, wired for dual operation, can be wired back and front to pass data either way)

Number 3 exists, but doesn't exist. Dont worry about number 3. It is somewhat manufacturer specific. You mostly either use Forward or Reverse. Forget any other extra terminology for now.

1. Host to Target - Allows you to connect the sas part of the cable (8087, 8643) as the Host, which is usually to the sas card. This usually terminates in 4 x SATA or SAS ports to plug into the Target, which is SAS drives or SATA hard drives.

2. Target to Host - Allows you to connect the 4 x SATA or 4 x SAS drives (which is the Target) to the Host, but in reverse order. So the use case scenario for this is you would connect 4 x Hard drives, to something like a backplane.

So yes, for your use case, you would need a Reverse Breakout Cable. Which in most cases, are cheaper than forward breakouts. So thats a plus.

Hope this helps explain it abit more.
 

JediAcolyte

Member
May 29, 2020
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US
Thanks for this thread. I was trying to remember and I should have known that someone else would have had the same issue.