“To expand or not to expand, that is the question”

Hi All.

My Supermicro X10SLM+F only has 3 PCI slots, and one is occupied by a 10Gbe network card… so, only two free

The problem is that I need to connect (via HBA) 8 internal hard drives, and 4 external hard drives.

I have available (already purchased and at home) the following:

  • 1x LSI SAS 9201-16i
  • 1x LSI SAS 9210-8i
  • 1x LSI SAS 9212-4i4e
  • 1x MiniSAS Adapter from SFF-8087 to SFF-8088
  • 1x Intel SAS Expander RES2SV240 (can be used without occupying a PCI slot, simply by powering it through MOLEX)

This allows many possible combinations, even using only two PCI slots. Which option is better? Why?

Some pictures from available hardware:

LSI SAS 9201-16i:

LSI SAS 9210-8i:

LSI SAS 9212-4i4e:

MiniSAS Adapter from SFF-8087 to SFF-8088:
MiniSAS Adapter from SFF-8087 to SFF-8088

Intel SAS Expander RES2SV240:

The X10-SLM has 2 8x slots and a 4x slot (electrical)

Use the 16i card + the externalising adapter in an 8x slot.

This gives you support for 12 internal, and 4 external drives without using a sas expander, and leaves you with a spare pcie slot, that you can use to host a pair of nvme drives.

The bandwidth will be about 4GB/s iirc correctly. Which is 333MB/s per drive you have, or 250MB/s if you fully populate. Which is plenty for HDs.

The 10gbe adapter should be in the 4x slot.

Whenever possible, I would try to keep the NIC on CPU lanes, in a x8 slot, to avoid oversubscribing the x4 link between CPU and chipset.

If your drives are SATA, the -4i4e does the job.

If the drives are SAS and/or this is a virtualised setting and the HBA has to be passed through, you have no said that, the -16i and SFF-8088 in front of an unused slot.

Thanks for your answers!

Some information is missing: The system is not virtualized, and the hard drives are all SATA.

Let other friends give their opinion: Is it better to expand the 9210-8i or use the 9201-16i?

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Believe it or not, I’ve tried one of these adapters to connect external drives and… they don’t work! For some reason I can’t understand.

On the other hand, the LSI SAS 9212-4i4e worked perfectly. Which narrows the problem down to the adapter.

Does anyone have experience with these adapters? I thought they were totally passive and there was no chance they wouldn’t work.

MiniSAS Adapter from SFF-8087 to SFF-8088:

MiniSAS Adapter from SFF-8087 to SFF-8088

Faulty adapter or exceeding cable length?

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Thanks Stux, I think you are right.

In SFF-8087 cable from the HBA to the adapter is 50 cm (1.6 ft).
And the cable from the adapter to the external hard drives is 200 cm (6.6 ft).
That clearly exceeds the 200 cm (6.6 ft) maximum of the eSATA specifications.

I am going to buy a 100 cm (3.3 ft) eSATA cable which will probably solve the problem.

The last leg from a sas expander to a sata drive is over sata, and thus sata cable limits apply, not sas.

You would normally run external sas to a sas expander in a jbod chassis, and then that expander breaks out to a backplate, which is where the sata drives are, thus expander to backplane distance is not too great

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To reinforce this, it’s the total length of cables that matters here. In the plan as described one would be 0.5 m over spec (0.5 m + 1 m = 1.5 m).

Also I am curious about the use of “eSATA”. Can you link the cable you’re getting? I would have expected an SFF-8088 cable, since that is what goes into the adapter you linked. But maybe you’re getting an SFF-8088 to eSATA fanout cable[1].


  1. If so, if you can’t find one shorter tha 1 m, the remaining solution would be to do as @etorix said, use the 9212-4i4e and use the motherboards SATA for the remaining internal drives. ↩︎

Remember, if you are not using a server case then HBA will get hot. Attaching a fan to its heatsink will eat up physical space making the PCIE slot below it unusable :frowning:

Where the SAS standard ends and SATA begins is a question I’ve always had. Thanks again Stux.

If I’m right, with my JBOD chassis I’m getting into eSATA territory, so the maximum would be 2m. Is this correct? Here’s the chassis:

Century CRPR35E4U3IS:

And this is the cable I bought:

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This JBOD chassis is very convenient because it’s trayless. It allows me to put the hard drives in and out very easily/quick. I use it basically for cold backup, and I handle quite a few drives.

Century CRPR35E4U3IS:

The problem is that it’s an oven! Although it has two fans, they are small, and it’s easy for the hard drives to reach 50ºC on hot days… :scream:

That’s why I want a new one. The requirements are:

  • 4 hard drives.
  • Trayless.
  • SAS (SFF-8088?). How???
  • Good cooling: 8, 9 or 12 cm. fans (the idea is to modify them with Noctua fans).

And then, I need another one to use with an old Intel Mac Pro with an eSATA card (Sonnet ATA6-PRO-E4). The requirements are:

  • 4 hard drives.
  • Trayless.
  • eSATA, 4 ports.
  • No SATA multipliers.
  • Good cooling: 8, 9 or 12 cm. fans (the idea is to upgrade to Noctua fans).

Please, any suggestions for a JBOD chassis?
This is the only decent one I found: :sweat_smile:

iStarUSA BPN-DE340P
BPN-DE340P_02

iStarUSA S-35EX

S-35EX_02

iStarUSA S-3B-ATL-JB

S-3B-ATL-JB_02

All look like ovens… For that sizes you would likely have better luck with a 3D printer.

No personal experience with it, but the STH review is good:

There is an 8-bay sibling as well.

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Make sure to read the bottom part of that article though.