Question about expanding single JBOD to dual JBOD (single 8088 to dual 8087?)

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IamSpartacus

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Mar 14, 2016
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Currently I'm running this HBA going to this 2Ports Mini SAS SFF-8088 To 36Pin SFF-8087 PCBA Female Adapter card in a JBOD case which houses 8 SATA spinner disks. I'm looking to add a second identical JBOD case and connected it up to the same HBA. It looks like a single SFF-8088 cable going to each JBOD case would suffice in terms of bandwidth as I only have about 16Gbps in possible bandwidth coming off the 8 spinners (250MBps each = 2Gbps each).

I know I will need SAS2 expanders in each JBOD case. My question is, will something like these work to connect a single SFF-8088 cable to dual mini-SAS cables into a SAS2 expander? Or is each mini-SAS cable matched up with one of the SFF-8088 cables and thus i'd only be able to conect 4 of my 8 disks that way?

Or can I just use the same 2Ports Mini SAS SFF-8088 To 36Pin SFF-8087 PCBA Female Adapter card and connect that 2 the SAS2 expander?


EDIT: Now I'm wondering if there is such a thing as a SAS2 expander that presents two external 8088 ports that I can connected directly to two JBOD enclosures instead of needing expanders in each JBOD chassis.
 
Last edited:

itronin

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Nov 24, 2018
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Denver, Colorado
from your second post:

I like your idea of moving to a 16 port card as it is probably the simplest solution and you already have your BOM to build your second JBOD assuming it is identical to the first. I'm a fan of your first JBOD, it was a very nice clean, straightforward, and elegant build. I like the approach of simply upgrading the HBA - your drives should sync up at 6Gbps and your case if it is the same as your first holds 8 drives. Fewer active components to cool and potentially break/troubleshoot.

from your first post:

The super micro external to internal is in essence the same as your 2 port SFF-8088 SFF-8087 female adapter except the 8087 cables are built-in. It is a 1:1 map as you guessed.

You could go the expander route and utilize the SFF-8088 - SFF-8087 female adapter with 2 SFF-8087 to SFF-8087 cables to attach to an expander and if it is say the ubiquitous HP expander (3Gbps for SATA though) for example just NOT use the expander's built-in SFF-8088. You'd need a 1 slot mining adapter to power the HP expander and of course mount it in some fashion maybe to the motherboard tray aligned with a slot on the back. This is a full height card. You could look at the DELL expander - I'm still working on building mine out though and trying to manufacture/design a good board solution to hold the DELL expander.
 

gregsachs

Active Member
Aug 14, 2018
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Don't use the HP expander. Seriously, just don't use it!
The Dell expander with dual external ports might be a really good option for you too, but the simplest is absolutely the -16e HBA.
 

IamSpartacus

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Mar 14, 2016
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Don't use the HP expander. Seriously, just don't use it!
The Dell expander with dual external ports might be a really good option for you too, but the simplest is absolutely the -16e HBA.
What HP expander are you referring to?
 

gregsachs

Active Member
Aug 14, 2018
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https://www.google.com/url?sa=t&rct...er-wiki.146/&usg=AOvVaw2jkDkTtYh2PMW0aefThxej
It is a bunch of internal ports and has a single sff-8088 port in PCI card format. Only runs sata drives at 1.5 or 3 gb/s, will not do 6gb/s. I found it too be flaky, but that may have been due to powering it via a mining pci slot, as it doesn't have any other way of getting power to it. Its primary positive is that it is very cheap, <$20 on the bay.
When I did my own JBOD, I started with the HP, and moved to an intel RES2V240 I believe is the part number. Worked much better, partially because it gets power via molex.
 

IamSpartacus

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Mar 14, 2016
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Yea I didn't even know about that card and that post is so old it wouldn't have hit my radar. But thanks for the warning.