Solved SATA to SFF-8643?

[fr33bsd]

Hi folks,

everybody knows SFF-8643 to SATA cables. There are also SFF-8087 to SATA cables and special SATA to SFF-8087 cables to be able to connect from SATA onboard connector to miniSAS backplane. But I read that by using special SATA to SFF-8087 cables you lose the ability for hot swaping, right?

My main question is, what about SATA to SFF-8643? Do you need special a SATA to SFF-8643 cable to connect from SATA onboard connector to backplane or can you simply use a SFF-8643 to SATA cable vice versa? Do special special a SATA to SFF-8643 cable exist?

 

[SirDice]

Many SATA controllers support hot-swapable too. You can't use a SATA controller to drive SAS disks but most (all?) SAS controllers can drive SATA disks.

 

[sko]

Normal "1:1" wired backplanes MIGHT work when connected to a SATA controller (check the datasheet of your backplane!) and hot-swapping is usually supported by all halfway modern SATA controllers. Port expanders definitely won't work, as well as most backplanes with "advanced" features such as nvme-support.
You also loose any capabilities of the backplane like e.g. locating a disk or getting a nice listing of the disks and their corresponding physical position (i.e. everything sesutil(8) related) and you also get all the drawbacks of SATA like e.g. only a single command queue and (much) lower throughput.

TBH, with prices of proper SAS HBAs nowadays (even with the currently inflated prices) I wouldn't waste a single cent on an adapter cable to use a SATA controller. If this is a home server just get yourself one of those "brown box" SAS2008 or 3008 HBAs (depending on the age/capabilities of your hardware) and you can make proper use of your backplane...

 

[SirDice]

I "salvaged" a couple of LSI SAS2008 based controllers from old hardware that was being thrown away. Those are excellent controllers and have good support on FreeBSD. They might be a little old but for my home servers they're perfect.

 

[fr33bsd]

There are also SFF-8087 to SATA cables and special SATA to SFF-8087 cables to be able to connect from SATA onboard connector to miniSAS backplane. But I read that by using special SATA to SFF-8087 cables you lose the ability for hot swaping, right?

They are called:
sata to sff-8087 mini sas reverse breakout cable

Description​

This reverse breakout cable by Delock can be used to connect internal SAS devices, e.g. an HDD backplane with Mini SAS connector to a controller with 4 SATA ports. The metal clips on the SATA connectors provide a snap-in connection.

Note​

• It is not possible to use SAS hard disks with a SATA controller.
• To connect a SAS controller with SFF-8087 to 4 SATA hard disks, you can use Delock item
83313 (forward breakout).

Specification​

• Connector:
host:
4 x SATA 7 pin >
device:
1 x Mini SAS SFF-8087 male
1 x 8 pin sideband pin header female
• Pin assignment: reverse breakout
• Serial Attached SCSI (SAS) specification
• Length incl. connector: ca. 0.5 m

System requirements​

• A free Mini SAS or SATA interface

>> sata to sff-8643 <<

Description​

This reverse breakout cable by Delock can be used to connect internal SAS devices, e.g. an HDD backplane with Mini SAS HD connector to a controller with 4 SATA ports. The metal clips on the SATA connectors provide a snap-in connection.

Note​

• It is not possible to use SAS hard disks with a SATA controller.
• To connect a SAS controller with SFF-8643 to 4 SATA hard disks, you can use
Delock item 83392 (forward breakout).

Specification​

• Connector:
host:
4 x SATA 7 pin >
device:
1 x Mini SAS HD SFF-8643 male
1 x 8 pin sideband pin header female
• Pin assignment: reverse breakout
• 12 Gbps Serial Attached SCSI (SAS) specification
• Length incl. connector: ca. 0.5 m

System requirements​

• A free Mini SAS or SATA interface

 

[fr33bsd]

Normal "1:1" wired backplanes MIGHT work when connected to a SATA controller (check the datasheet of your backplane!) and hot-swapping is usually supported by all halfway modern SATA controllers. Port expanders definitely won't work, as well as most backplanes with "advanced" features such as nvme-support.
You also loose any capabilities of the backplane like e.g. locating a disk or getting a nice listing of the disks and their corresponding physical position (i.e. everything sesutil(8) related) and you also get all the drawbacks of SATA like e.g. only a single command queue and (much) lower throughput.

TBH, with prices of proper SAS HBAs nowadays (even with the currently inflated prices) I wouldn't waste a single cent on an adapter cable to use a SATA controller. If this is a home server just get yourself one of those "brown box" SAS2008 or 3008 HBAs (depending on the age/capabilities of your hardware) and you can make proper use of your backplane...

True - then it is sata-only, of course.

Regarding the HBAs: Since I discovered that using atop on FreeBSD and Linux you get different (higher) workload values when one and the same drive is connected to SoC IO-SATA 6-Port-Controler of intel (D15xx) comparing to - as said - same drive connected to a HBA. The difference is factor between 9 and 11 or even more (!!), meaning during i.e. write ops a WD spin disk is busy by 67% delivering 10,95 MB/s at avio 3.35ms being connected to onboard intel soc controler on a supermicro mobo, but while using a HBA it is busy by 5% with same data rate and only avio 0.3ms. This is scary!

This kills your sata system even SATA is not designed for high production workloads, it should deliver better write performance on single sequential write approach, right? On Linux and FreeBSD I suffered dropps on write down to 10% of 1GBit thanks to intel-soc-power.

That's why I decided to go for Broadcom HBA 9300 and 9400 ...