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What's the difference between multilane, direct-attached HDD and expander for SAS backplanes?

Supermicro chassis description page

Direct attached HDD backplane (TQ version), multilane backplane (A version) and expanders' backplane (E1, E2 versions) are available for application specific solution optimization.

I'm guessing that direct-attached requires me to use a SFF-8087 fanout cable to each 4 disks, while multilane only requires 1 SFF-8087-to-SFF-8087 cable for each 4 disks, and finally an expander backplane allows me to use 1 SFF-8087-to-SFF-8087 for more than 4 disks?

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2 Answers 2

up vote 5 down vote accepted

Yes, that's all correct. I suppose it's not clear from the Supermicro product pages.

SAS SFF-8087 is a 4-lane multi-connection transport. It's typically used by RAID controllers and disk backplanes. You probably want to avoid anything that requires fanout cables. Expander backplanes can have some problems, depending on what types of disks and controllers will be in use.

Also this: How exactly does a SAS SFF-8087 breakout cable work? + RAID/connection questions

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The cable you'll use is dependent on the drive backplane and the disk controller you use. If both of them are SFF-8087, you can get an SFF-8087 straight cable, otherwise you might have to use a fan-out cable.

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Also, if you're using a SAS expander, you'll have one incoming SFF-8087 (depending on the expander) and output with probably more SFF-8087 cables. –  maverickbna Mar 15 at 2:11

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