SOLVED Use of SATA Backplane

[Alpha-Inc.]

Hello everybody,

I’m currently moving my internal TrueNAS hardware to a new case (server chassis). All the chassis I found use a SATA Backplane and I’ve never heard about those.
When I was first introduced into FreeNAS I was told not to use a hardware RAID-Controller since the RAID is done by FreeNAS/TrueNAS itself. Also, when the hardware controller breaks you have to use the exact same model in order for it work again (am I right?) Now I’m not sure if this rule also applies to a backplane or if I can simply use any SATA backplane when it breaks one day?

Also, my mainboard only has 4 SATA ports but 2 additional MiniSAS HD ports with which I can connect 8 drives. Is it possible use those MiniSAS HD cables to create the bridge between the SATA backplane and the mainboard or how to i connect my drives over the backplane while also powering them ?

 

[jgreco]

Might want to take a few moments to review our SAS Primer.

The comprehensive answer to your RAID controller question is here.

"SATA backplanes" are very rare and most of what you are finding are probably actually SAS backplanes. SATA introduces additional complexity and restrictions around the cabling and length.

Any competent chassis will already have solved the power wiring for the SAS backplane. You don't want to get involved with that engineering if you can avoid it. I had to write an entire power supply sizing sticky to help people who are doing this on their own. A chassis should come pre-engineered with a PSU and a backplane sized appropriately.

Since you probably do not have a SATA backplane, the 4 SATA ports on your mainboard probably aren't useful unless you add some SSD's for boot/jails/whatever.

If you get an SAS expander backplane, you can run dozens or hundreds of drives off your miniSAS HD ports; you are not limited to 8 drives, you have 8 *lanes*, which can be used to directly talk to up to 8 drives, or which can talk to an SAS expander, which in turn can talk to LOTS of drives.

Not all backplanes contain an SAS expander. For example, Supermicro backplanes ending in "A" just bring four SAS drives out to an SFF8087.

 

[HoneyBadger]

Welcome.

Have you had a chance to read through @jgreco 's excellent "Don't be afraid to be SAS-sy" resource? It makes an excellent primer on the behavior of SAS and SATA including backplanes and the different types (specifically those in Supermicro chassis, but the principles apply to others.)

Don't be afraid to be SAS-sy ... a primer on basic SAS and SATA

With the introduction of SAS 12Gbps, seems like "it's time" to do a braindump on SAS. Work in progress, as usual. History By the late '90's, SCSI and PATA were the dominant technologies to attach disks. Both were parallel bus multiple drop...

www.truenas.com

When I was first introduced into FreeNAS I was told not to use a hardware RAID-Controller since the RAID is done by FreeNAS/TrueNAS itself. Also, when the hardware controller breaks you have to use the exact same model in order for it work again (am I right?)

First point is correct, it's a bad idea. Second point is "mostly correct" in that the same vendor is usually possible, but since you won't be using a hardware RAID card (see point #1) it won't matter. ;)

Now I’m not sure if this rule also applies to a backplane or if I can simply use any SATA backplane when it breaks one day?

Think of a SAS backplane like a switch - as long as the technology is compatible, it's like swapping brands.

Also, my mainboard only has 4 SATA ports but 2 additional MiniSAS HD ports with which I can connect 8 drives. Is it possible use those MiniSAS HD cables to create the bridge between the SATA backplane and the mainboard or how to i connect my drives over the backplane while also powering them ?

SAS/SATA cables don't carry power cables of course - backplanes usually have separate (Molex or other) plugs to feed them the amperage needed to spin 12 or more disks as a time. Make sure your PSU has enough quantity/compatible plugs, or buy the chassis as a complete unit with PSUs.

You'll likely be able to use the motherboard ports for the data connection, unless your board specifically only speaks the SATA protocol on those ports and they're just using the MiniSAS HD (SFF-8643) connector because it's smaller. (Unlikely, especially if it's a Supermicro.)

Post the model number of the board and we'll suss that out; the rest of the system details would be appreciated as well if you can.

Cheers!

 

[Alpha-Inc.]

Welcome.

Have you had a chance to read through @jgreco 's excellent "Don't be afraid to be SAS-sy" resource? It makes an excellent primer on the behavior of SAS and SATA including backplanes and the different types (specifically those in Supermicro chassis, but the principles apply to others.)

Don't be afraid to be SAS-sy ... a primer on basic SAS and SATA

With the introduction of SAS 12Gbps, seems like "it's time" to do a braindump on SAS. Work in progress, as usual. History By the late '90's, SCSI and PATA were the dominant technologies to attach disks. Both were parallel bus multiple drop...

www.truenas.com

First point is correct, it's a bad idea. Second point is "mostly correct" in that the same vendor is usually possible, but since you won't be using a hardware RAID card (see point #1) it won't matter. ;)


Think of a SAS backplane like a switch - as long as the technology is compatible, it's like swapping brands.


SAS/SATA cables don't carry power cables of course - backplanes usually have separate (Molex or other) plugs to feed them the amperage needed to spin 12 or more disks as a time. Make sure your PSU has enough quantity/compatible plugs, or buy the chassis as a complete unit with PSUs.

You'll likely be able to use the motherboard ports for the data connection, unless your board specifically only speaks the SATA protocol on those ports and they're just using the MiniSAS HD (SFF-8643) connector because it's smaller. (Unlikely, especially if it's a Supermicro.)

Post the model number of the board and we'll suss that out; the rest of the system details would be appreciated as well if you can.

Cheers!

Hey, first of all thank you for your reply.

I think I was referring to a SAS backplane when writing SATA Backplane ^^ Thank's for the clarification.

I'm using a Supermicro A2SDi-H-TP4F but I haven't found a fitting Backplane / Server chassis yet.

 

[HoneyBadger]

Supermicro A2SDi-H-TP4F

Hmm. Unfortunately that board is the exception to the rule and does only speak SATA on those ports, according to the spec sheet:

A2SDi-H-TP4F | Motherboards | Products | Supermicro

SoC controller for 12 SATA3 (6 Gbps) ports; 4 SATA3 ports, 2 MiniSAS HD ports

So you'll need to opt for a "TQ" or "Direct-Connect" style backplane that has 12 SATA ports, as well as get yourself a pair of SFF-8643 to SATA "forward breakout" cables - those along with the four onboard SATA ports should fully service the bays, just do some careful management internally to avoid Cable Spaghetti.