Connecting Server Backplane to Motherboard?

[MichaelCropper]

Ok, so I've just purchased a handful of components and I'm in the process of building a server from individual components. First hurdle... how do you connect the hard drives to the motherboard? On the backplane, there are 5x SFF8087 connectors (I think) on a 20x SATA disk setup.

 

1) Why are there 5x connectors?

2) Do all 5x need to be connected to the motherboard via a SAS Controller, or only one?

3) Does it matter how many ports the SAS Controller has? i.e. if there are 5x SFF8087 ports, does that mean this should be coupled with a 5 Port SAS Controller? What limiting factor does this have one way or another?

4) Is there any difference between a SAS Controller and a SAS Raid Controller? I was planning on managing the RAID via Ubuntu (which I've still got to figure out that part too...)

[WereCatf]

8 minutes ago, MichaelCropper said:

1) Why are there 5x connectors?

2) Do all 5x need to be connected to the motherboard via a SAS Controller, or only one?

3) Does it matter how many ports the SAS Controller has? i.e. if there are 5x SFF8087 ports, does that mean this should be coupled with a 5 Port SAS Controller? What limiting factor does this have one way or another?

4) Is there any difference between a SAS Controller and a SAS Raid Controller? I was planning on managing the RAID via Ubuntu (which I've still got to figure out that part too...)

1 and 2) One SFF8087-connector can be split up into 4 SATA-connectors, so for a 20-drive setup, 5 SFF8087-connectors is right.

3) Yes, obviously you'll need as many or more ports as you have SFF8087-connectors on the backplane, if you plan to use all the drive-bays on it.

[Falconevo]

15 minutes ago, MichaelCropper said:

Ok, so I've just purchased a handful of components and I'm in the process of building a server from individual components. First hurdle... how do you connect the hard drives to the motherboard? On the backplane, there are 5x SFF8087 connectors (I think) on a 20x SATA disk setup.

 

1) Why are there 5x connectors?

2) Do all 5x need to be connected to the motherboard via a SAS Controller, or only one?

3) Does it matter how many ports the SAS Controller has? i.e. if there are 5x SFF8087 ports, does that mean this should be coupled with a 5 Port SAS Controller? What limiting factor does this have one way or another?

4) Is there any difference between a SAS Controller and a SAS Raid Controller? I was planning on managing the RAID via Ubuntu (which I've still got to figure out that part too...)

Sounds like you have a SAS back plane with a potential SAS expander (5th port) but would need a pic of it to be sure or the model number, you will need a HBA/RAID controller that has a minimum of 5x SAS 8087 ports on it.

Try and find something like a 9820 LSI MegaRAID controller, they usually come with 4+ ports on them.

*Edit* 
Here's a link to one on eBay;

https://www.ebay.co.uk/itm/LSI-MegaRAID-SAS-9280-24i4e-LSI00211-24-port-internal-4-Port-External-RAID-cont/272426167055

[MichaelCropper]

This is what I'm working with at the moment, https://www.silverstonetek.com/product.php?pid=544&area=en, a Silverstone RM420. From what I can tell, if I get a SAS Controller that supports at least 5x Physical Ports, which is likely to be either something similar to that Mega RAID, then if I purchase SAS <---> SAS cables such as these, https://www.scan.co.uk/products/50cm-silverstone-cps02-shielded-mini-sas-36pin-to-36pin-cable-heavy-duty-ssf-8087-connectors, then that should work I would have thought? I was originally thinking about using a SAS --> 4x splitter cable, but looking closer, these only seem to work when it is SAS --> SATA, whereas since the SAS Controller has physical SAS connectors on and the server chassis backplane has 5x physical SAS connectors on, then it looks like 5x port-to-port cables are required, which increases the cost of the SAS Controller naturally. 

[Mikensan]

To get 6 SAS ports, you can buy 1 SAS controller which typically has 2 SAS ports, and a SAS expander which has 6. Assuming you're using mechanical disks, this won't be an issue.

 

Or you could buy 3x 2 port SAS controllers.

 

Most the time backplanes have expanders built into them (like R610 servers do), but the one you linked does not. It's using the default 4 ports per SAS, which is good because some people way want to use SSDs.

[MichaelCropper]

Interesting, I didn't know that. How do you know the chassis doesn't have a SAS Expander? Would you normally expect to see this listed as a specific piece of information on the spec, and since it isn't there then it doesn't have one?

 

So would something like this do; SAS Controler, https://www.scan.co.uk/products/8-port-highpoint-rocketraid-2720sgl(rr2720)-internal-pci-e-20-x8-to-sas-sata-iii-raid-controller-oem, + SAS Expander, https://www.ebay.co.uk/itm/HP-24-Bay-SAS-Expander-Card-487738-001-468405-001-NEW/232811636832 ? Or as you say, 3x SAS Controllers. Is there any pros/cons for each approach? I'd guess that if you wanted to use RAID, then having 3x SAS Controllers would only RAID the disks that are connected to that specific card, rather than RAID the entire disk array? Again, I'm not sure if one or the other is any better for this scenario. 

[Electronics Wizardy]

3 hours ago, MichaelCropper said:

Interesting, I didn't know that. How do you know the chassis doesn't have a SAS Expander? Would you normally expect to see this listed as a specific piece of information on the spec, and since it isn't there then it doesn't have one?

 

So would something like this do; SAS Controler, https://www.scan.co.uk/products/8-port-highpoint-rocketraid-2720sgl(rr2720)-internal-pci-e-20-x8-to-sas-sata-iii-raid-controller-oem, + SAS Expander, https://www.ebay.co.uk/itm/HP-24-Bay-SAS-Expander-Card-487738-001-468405-001-NEW/232811636832 ? Or as you say, 3x SAS Controllers. Is there any pros/cons for each approach? I'd guess that if you wanted to use RAID, then having 3x SAS Controllers would only RAID the disks that are connected to that specific card, rather than RAID the entire disk array? Again, I'm not sure if one or the other is any better for this scenario. 

Get a internal sas expander, that one is for external connectors. Get something like thishttps://www.ebay.com/itm/Intel-RAID-24-Port-Expander-Card-RES2SV240-SAS-SATA-PCI-E-FREE-SHIPPING/163152322386?hash=item25fca2df52%3Ag%3A6SUAAOSwSCZbTPW5&_sacat=0&_nkw=intel+sas+expander&_from=R40&rt=nc&_trksid=p2380057.m570.l1311.R1.TR2.TRC0.A0.H0.Xintel+sas.TRS0

 

For sas controller, you want a hba, not a raid card. Also stay away from highpoint, there known for not being great, and that is a low end raid card, you don't want that. Id get something like this. Its a rebranded lsi card.

 

https://www.ebay.com/itm/NEW-Dell-PERC-H200-6Gb-PCI-e-SAS-SATA-8-Port-Raid-Controller-From-US-Ship/192560383405?epid=1223070165&hash=item2cd57e45ad%3Ag%3ADMEAAOSwKRBbF7L9&_sacat=0&_nkw=dell+h200&_from=R40&rt=nc&_trksid=p2380057.m570.l1313.TR1.TRC0.A0.H0.Xdell+h200.TRS1

[Helly]

8 hours ago, Electronics Wizardy said:

Get a internal sas expander, that one is for external connectors.

The HP is not for external connectors. It has 6 8087 ports on it, which are internal. It also has 1 external connector. That card can be used but there is a chance the raid/hba card you connect it to does not support it. If you do buy the HP, make sure it has an updated firmware. The original firmware only supports SATA1 speeds (1.5Gbps). You need to make sure the one you're buying has at least firmware 1.52 (that updates speeds to 3Gbps). Because its impossible to update the firmware without an original HP raid/hba card. Also make sure its a green PCB and not a yellow one. The yellow ones are older and cant be updated at all.

 

i recently obtained the HP card myself, which is why i know all this :P.

 

Or go with the intel card, it was a lot more expensive for me though :(.

[gamerking]

16 hours ago, MichaelCropper said:

Ok, so I've just purchased a handful of components and I'm in the process of building a server from individual components. First hurdle... how do you connect the hard drives to the motherboard? On the backplane, there are 5x SFF8087 connectors (I think) on a 20x SATA disk setup.

 

1) Why are there 5x connectors?

2) Do all 5x need to be connected to the motherboard via a SAS Controller, or only one?

3) Does it matter how many ports the SAS Controller has? i.e. if there are 5x SFF8087 ports, does that mean this should be coupled with a 5 Port SAS Controller? What limiting factor does this have one way or another?

4) Is there any difference between a SAS Controller and a SAS Raid Controller? I was planning on managing the RAID via Ubuntu (which I've still got to figure out that part too...)

it depends on the Backplane if it includes a expander built in then find the manual and read up on it , from my time looking up mine for my 2u 12bay server there is pass thur ones and redundant ones if you got a redundant one then only 1-2 are needed but need a sas to sas cable for all the bays to work . find the part # on the backplane and look it up . for passthur ones if you want all 20 bays you need all 5 cables .

 

i went with a LSI HBA for the quickest setup , the intel expander above is what im getting when i need to expand my pool , another option if you only need 2-8 drives are reverse SAS to sata cables . these are needed if the Backplane has a SAS port and you want to attach the HDD's to a MB or card that has SATA ports , normal  breakout cables i was told wont for this .

 

if you mean a HBA its just a way to let the OS see the drives all it does is pass any it sees thur , Raid card will do raid before the OS sees the drive/ pool

[Mikensan]

17 hours ago, MichaelCropper said:

How do you know the chassis doesn't have a SAS Expander? Would you normally expect to see this listed as a specific piece of information on the spec, and since it isn't there then it doesn't have one?

If it breaks out into groups of 4. I wouldn't say it's really ever in specs but you can tell pretty quickly by looking at pictures. I would say when buying a case with a backplane, more often than not it won't have an expander. Usually it will have SAS connectors or SATA connectors.

[MichaelCropper]

Thanks all, some really good advice here