Not that new of an idea. I had to use their Thunderbolt to 8Gb Fibre Channel adapters in setting up a test system for 16 Mac Minis to a FC backup storage appliance about 4 years ago.
SF-8644 are not limited to 4 drives in an SAS system. True, the 8644 contains lanes for 4 drives but under SAS standards if your controller supports it you can multiplex up to a 128 drives on SAS so with a proper backplane you should be able to multiplex a large number of drives over that SF-8644, I'm curious if this would support that or if the thunderbolt connection puts a hard limit on the numbers of Drives.
For those curious about this SAS capability I'll share my own setup. My home server uses a LSI 9561-4i card (4 port SAS raid card that uses the SF-8644 connection for the cabeling). I run a dual ended 8644 cable to my 24 drive backplane attached to a supermicro SC846BE16-R920B [https://www.supermicro.com/products/chassis/4U/846...]). Because SAS supports up to 128 drives per controller I'm able use a 4 port 12gbps Raid card to control a 24 drive array.
But I'm willing to bet the Thunderbolt connection just means their using the SF-8644 plug for it's 1 to 4 octopus cable to connect to 4 separate drives. It would be cool through if included a raid controller and actually allowed you to fully utilize the SAS connection.
I think Thunderbolt multiplexes everything, where it sends it to the host to get de-multiplexed. What's on the data wire (in this case, SAS) shouldn't matter to it, as I don't think Thunderbolt even has an understanding of what a drive is. Imagine if every Thunderbolt controller had to support every arbitrary protocol passing through it, Asprin would be in short supply.
Thunderbolt just transports PCIe and DisplayPort packets over a fast serial link. So this would behave no differently than the same controller on a PCIe 3.0 x4 add-in card, with a little added latency since everything has to traverse several PCIe switches along the way. I suppose ATTO’s implementation and drivers might also impact which features are supported. But Thunderbolt connected devices look like any other PCIe devices to the host.
Right, this is essentially the same HBA but in an external Thunderbolt 3 enclosure, for which you’re paying a premium. This is for when you need to add a couple SF-8644 miniSAS ports to your laptop or Mac that has Thunderbolt 3 but no internal PCIe slots that you can pop a regular add-in card into.
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dgingeri - Friday, May 11, 2018 - link
Not that new of an idea. I had to use their Thunderbolt to 8Gb Fibre Channel adapters in setting up a test system for 16 Mac Minis to a FC backup storage appliance about 4 years ago.rahvin - Friday, May 11, 2018 - link
SF-8644 are not limited to 4 drives in an SAS system. True, the 8644 contains lanes for 4 drives but under SAS standards if your controller supports it you can multiplex up to a 128 drives on SAS so with a proper backplane you should be able to multiplex a large number of drives over that SF-8644, I'm curious if this would support that or if the thunderbolt connection puts a hard limit on the numbers of Drives.For those curious about this SAS capability I'll share my own setup. My home server uses a LSI 9561-4i card (4 port SAS raid card that uses the SF-8644 connection for the cabeling). I run a dual ended 8644 cable to my 24 drive backplane attached to a supermicro SC846BE16-R920B [https://www.supermicro.com/products/chassis/4U/846...]). Because SAS supports up to 128 drives per controller I'm able use a 4 port 12gbps Raid card to control a 24 drive array.
But I'm willing to bet the Thunderbolt connection just means their using the SF-8644 plug for it's 1 to 4 octopus cable to connect to 4 separate drives. It would be cool through if included a raid controller and actually allowed you to fully utilize the SAS connection.
rahvin - Friday, May 11, 2018 - link
Mistyped, 9361-4i [https://www.broadcom.com/products/storage/raid-con...], boo to LSI being purchased by Avago who then sold out to evil Broadcom.dgingeri - Friday, May 11, 2018 - link
Actually, evil Broadcom was bought out by even more evil Avago, who then changed their name to seem like the slightly less evil Broadcom.SSNSeawolf - Friday, May 11, 2018 - link
I think Thunderbolt multiplexes everything, where it sends it to the host to get de-multiplexed. What's on the data wire (in this case, SAS) shouldn't matter to it, as I don't think Thunderbolt even has an understanding of what a drive is. Imagine if every Thunderbolt controller had to support every arbitrary protocol passing through it, Asprin would be in short supply.repoman27 - Saturday, May 12, 2018 - link
Thunderbolt just transports PCIe and DisplayPort packets over a fast serial link. So this would behave no differently than the same controller on a PCIe 3.0 x4 add-in card, with a little added latency since everything has to traverse several PCIe switches along the way. I suppose ATTO’s implementation and drivers might also impact which features are supported. But Thunderbolt connected devices look like any other PCIe devices to the host.jab701 - Saturday, May 12, 2018 - link
$895?A broadcom (LSI) SAS HBA (non-raid) card is cheaper than that and goes inside your PC...
For $512 you can get one of these (https://www.pc-pitstop.com/sas_hba/9400-16I.asp) which supports 16 drives without an expander and NVMe too
repoman27 - Saturday, May 12, 2018 - link
Right, this is essentially the same HBA but in an external Thunderbolt 3 enclosure, for which you’re paying a premium. This is for when you need to add a couple SF-8644 miniSAS ports to your laptop or Mac that has Thunderbolt 3 but no internal PCIe slots that you can pop a regular add-in card into.