FireWire/800 to SATA | FC (optic) to SAS/SATA

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shutitalldown
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FireWire/800 to SATA | FC (optic) to SAS/SATA

Unread postby shutitalldown » Wed Apr 18, 2018 4:40 am

I have developed an external storage device able to provide thousand IOP on both sequential and random r/w accesses with a bandwidth of 120Mbyte/sec per channel, but I had to use the SATA1 interface (under intellectual property copyright for the hardware chip I had to use), and now I have four SATA1 plugs waiting for a *solution*.

These storage devices need to be used in RAID-0 stripping. 70-80Mbyte/sec per single device is acceptable.

On the host side, I must (it's a constraint) use the PCI-X, and it seems I have only three choices on a rack machine to connect the external storage:

  • 1) SFF8470 multilane 4X SAS-->SATA by a PCI-X@133Mhz adapter. SIL's are fine for this.
  • 2) four firewire/800 cables, attached to a four fw/800 PCI-X@133Mhz adapter. Adaptec's are fine for this.
  • 3) FC--optic--FC cable, attached to a FC PCI-X@133Mhz adapter. QLOGIC's are fine for this.

1) The first solution
requires:
- qty=1, SFF8470-to-SFF8470
- qty=1, SFF8470 SFF8470-Slotblech-adapter-to-SAS (I can modify the storage cabinet)

those cables and slotblech adpters are a bit expensive (~ 90E/cable, 30E/slotbench)

2) The second solution
requires:
- qty=4, firewire/800 cables (bonding configuration, not chained, my PCI-X-FW/800 supports it)

I have never seen any firewire/1600, that would be COOL, anyway, the firewire itself is cool since it supports advanced features like DMA and peer-to-peer transfers. The understanding of FireWire and USB specifications does nothing to diminish the warning that some OEMs tie the these two together in their combo-solutions where they are prone to use a chip able to drive the USB2 bulk protocol, and the SBP2-b protocol, but with the bandwidth of the USB2. I have a direct bad experience with such attitude, and the Firewire/800 combo USB adapter to SATA can't provide more than 40Mbyte/sec even if the storage device has already shown better performance, up to 120Mbyte/sec on a SATA link.

I can claim the above because a friend lent me his FW/800 disk adapter (it's fw/800 only), I plugged my SATA-device in, and once connected to my Firewire/800 PCI-X card, the same system was able to perform up to 80Mbyte/sec!

The difference between before, and after, is the Firewire-to-SATA adapter on the storage box. Mine is a combo USB, and it's shitty.

3) Concerning the third solution

... well ... I can, in theory, use an FC (optic) adapter, e.g. QLOGIC happens to have some PCIX@133Mhz adapter for the fiber channel, whose benefits are -a smaller cable- and -a larger bandwidth- (200Mbyte/sec, at least)

The problem with FC is ... what to buy? I know there are a few rack-mountable units able to accept SFP and drive disk attached to 4 mini-SAS QSFP cables, while other FC-solutions are usually on the way of the big array of disks choice, whereas I only need to connect four SATA1 devices to *something* on the PCI-X of a linux-non-x86 system.

hints?
thanks :)
I am tattooed in reverse, cause if you break rules you don't know where it leads.
But, say, all the venus in furs are so manically depressed and manically dressed.

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jan-jaap
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Re: FireWire/800 to SATA | FC (optic) to SAS/SATA

Unread postby jan-jaap » Wed Apr 18, 2018 5:18 am

Re. FireWire: unlike USB, FireWire doesn't need hubs to create a topology of nodes. That's because most FireWire nodes have more than one (often 3) ports. Usually, every disk, host adapter, webcam etc is one node. Every node can then be connected to 3 other nodes, and together they form the FW topology.

The bandwidth of the entire FireWire 800 topology is 800Mb/s. If you connect 1 external FW800 disk to one of the 3 ports of the host adapter, it has the 800Mb/s bandwidth all to itself. But if you connect 3 external FW800 disks to the 3 ports of one FW800 node (the host adapter), they share the 800Mb/s bandwidth!

Each FireWire node needs a link layer and a PHY. These are usually separate chips, often made by TI. Looking at the chips on your FW800 adapter, it should be easy to figure out whether it implements one or more nodes. My bet is on a single node, with 3 ports.

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shutitalldown
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Re: FireWire/800 to SATA | FC (optic) to SAS/SATA

Unread postby shutitalldown » Wed Apr 18, 2018 5:51 am

The Sonnet FW/800 comes with three ports and 1 chip, while my Adaptec FW/800 card comes with two chip and four ports, that means 40Mbyte/port: none of them is acceptable :roll:
I am tattooed in reverse, cause if you break rules you don't know where it leads.
But, say, all the venus in furs are so manically depressed and manically dressed.


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