OCZ's Fastest SSD, The IBIS and HSDL Interface Reviewed

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• Ushio01 - Wednesday, September 29, 2010 - link

  My mistake.

• Kevin G - Wednesday, September 29, 2010 - link

  I have had a feeling that SSD's would quickly become limited by the SATA specification. Much of what OCZ is doing here isn't bad in principle. Though I have plenty of questions about it.
  
  Can the drive controller fall back to SAS when plugged into a motherboard's SAS port? (Reading the article, I suspect a very strong 'no' answer.) Can the HSDL spec and drive RAID controller be adapted to support this?
  
  What booting limitations exist? Is a RAID driver needed for the controller inside the IBIS drive?
  
  Are the individual SSD controllers connected to the drive's internal RAID controller seen by the operating system or BIOS? (I'd guess 'no' but not explicitly stated.)
  
  Is the RAID controller on the drive seen as a PCI-E device?
  
  Is the single port host card seen by the system's operating system or is entirely passive? Is the four HDSL port card seen differently?
  
  Does the SAS cabling handle PCI-E 3.0 signaling?
  
  Is OCZ working on a native HDSL controller that'll convert PCI-E to ONFI? Would such a chip be seen as a regular old IDE device for easy OS installation and support for legacy systems? Would such a chip be able to support TRIM?

• disappointed1 - Wednesday, September 29, 2010 - link

  I've read Anandtech for years and I had to register and comment for the first time on what a poor article this is - the worst on an otherwise impressive site.
  
  "Answering the call many manufacturers have designed PCIe based SSDs that do away with SATA as a final drive interface. The designs can be as simple as a bunch of SATA based devices paired with a PCIe RAID controller on a single card, to native PCIe controllers."
  -And IBIS is not one of them - if there is a bunch of NAND behind a SATA RAID controller, then the final drive interface is STILL SATA.
  
  "Dubbed the High Speed Data Link (HSDL), OCZ’s new interface delivers 2 - 4GB/s (that’s right, gigabytes) of bi-directional bandwidth to a single SSD."
  -WRONG, HSDL pipes 4 PCIe 1.1 lanes to a PCIe to PCI-X bridge chip (as per the RevoDrive), connected to a SiI 3124 PCI-X RAID controller, out to 4 RAID'ed SF-1200 drives. And PCIe x4 is 1000MB/s bi-directional, or 2000MB/s aggregate - not that it matters, since the IBIS SSDs aren't going to see that much bandwidth anyway - only the regular old 300MB/s any other SATA300 drive would see. This is nothing new; it's a RevoDrive on a cable. We can pull this out of the article, but you're covering it up with as much OCZ marketing as possible.
  
  Worse, it's all connected through a proprietary interface instead of the PCI Express External Cabling, spec'd Febuary 2007 (http://www.pcisig.com/specifications/pciexpress/pc...
  
  By your own admission, you have a black box that is more expensive and slower than a native PCIe x4 2.0, 4 drive RAID-0. You can't upgrade the number of drives or the drive capacity, you can't part it out to sell, it's bigger than 4x2.5" drives, AND you don't get TRIM - the only advantage to using a single, monolithic drive. It's built around a proprietary interface that could (hopefully) be discontinued after this product.
  
  This should have been a negative review from the start instead of a glorified OCZ press release. I hope you return to objectivity and fix this article.
  
  Oh, and how exactly will the x16 card provide "an absolutely ridiculous amount of bandwidth" in any meaningful way if it's a PCIe x16 to 4x PCIe x4 switch? You'd have to RAID the 4 IBIS drives in software and you're still stuck with all the problems above.

• Anand Lal Shimpi - Wednesday, September 29, 2010 - link

  I appreciate you taking the time to comment. I never want to bring my objectivity into question but I will be the first to admit that I'm not perfect. Perhaps I can shed more light on my perspective and see if that helps clear things up.
  
  A standalone IBIS drive isn't really all that impressive. You're very right, it's basically a RevoDrive in a chassis (I should've mentioned this from the start, I will make it more clear in the article). But you have to separate IBIS from the idea behind HSDL.
  
  As I wrote in the article the exciting thing isn't the IBIS itself (you're better off rolling your own with four SF-1200 SSDs and your own RAID controller). It's HSDL that I'm more curious about.
  
  I believe the reason to propose HSDL vs. PCIe External Cabling has to do with the interface requirements for firmware RAID should you decide to put several HSDL drives on a single controller, however it's not something that I'm 100% on. From my perspective, if OCZ keeps the standard open (and free) it's a non-issue. If someone else comes along and promotes the same thing via PCIe that will work as well.
  
  This thing only has room to grow if controller companies and/or motherboard manufacturers introduce support for it. If the 4-port card turns into a PCIe x16 to 4x PCIe x4 switch then the whole setup is pointless. As I mentioned in the article, there's little chance for success here but that doesn't mean I believe it's a good idea to discourage the company from pursuing it.
  
  Take care,
  Anand

• Anand Lal Shimpi - Wednesday, September 29, 2010 - link

  I've clarified the above points in the review, hopefully this helps :)
  
  Take care,
  Anand

• disappointed1 - Thursday, September 30, 2010 - link

  Thanks for the clarification Anand.

• Guspaz - Wednesday, September 29, 2010 - link

  But why is HSDL interesting in the first place? Maybe I'm missing some use case, but what advantage does HSDL present over just skipping the cable and plugging the SSD directly into the PCIe slot?
  
  I might see the concept of four drives plugged into a 16x controller, each getting 4x bandwidth, but then the question is "Why not just put four times the controllers on a single 16x card."
  
  There's so much abstraction here... We've got flash -> sandforce controller -> sata -> raid controller -> pci-x -> pci-e -> HSDL -> pci-e. That's a lot of steps! It's not like there aren't PCIe RAID controllers out there... If they don't have any choice but to stick to SATA (and I'd point out that other manufacturers, like Fusion-IO decided to just go native PCIe) due to SSD controller availability, why not just use PCIe RAID controller and shorten the path to flash -> sandforce controller -> raid controller -> pci-e?
  
  This just seem so convoluted, while other products like the ioDrive just bypass all this.

• bman212121 - Wednesday, September 29, 2010 - link

  What doesn't make sense for this setup is how it would be beneficial over just using a hardware RAID card like the Areca 1880. Even with a 4 port HSDL card you would need to tie the drives together somehow. (software raid? Drive pooling?) Then you have to think about redundancy. Doing raid 5 with 4 Ibis drives you'd lose an entire drive. Take the cards out of the drives, plug them all into one Areca card and you would have redundancy, RAID over all drives + hotswap, and drive caching. (RAM on the Areca card would still be faster than 4 ibis)
  
  Not seeing the selling point of this technology at all.

• rbarone69 - Thursday, September 30, 2010 - link

  In our cabinets filled with blade servers and 'pizza box' severs we have limited space and a nightmare of cables. We cannot afford to use 3.5" boxes of chips and we dont want to manage an extra bundle of cables. Having a small single 'extension cord' allows us to store storage in another area. So having this kind of bandwidth dense external cable does help.
  
  Cabling is a HUGE problem for me... Having fewer cables is better so building the controllers on the drives themselves where we can simply plug them into a port is attractive. Our SANs do exactly this over copper using iSCSI. Unfortunatly these drives aren't SANs with redundant controllers, power supplies etc...
  
  Software raid systems forced to use the CPU for parity calcs etc... YUK Unless somehow they can be linked and RAID supported between the drives automagically?
  
  For supercomputing systems that can deal with drive failures better, I can see this drive being the perfect fit.

• disappointed1 - Wednesday, September 29, 2010 - link

  Can the drive controller fall back to SAS when plugged into a motherboard's SAS port? (Reading the article, I suspect a very strong 'no' answer.) Can the HSDL spec and drive RAID controller be adapted to support this?
  -No, SAS is a completely different protocol and IBIS houses a SATA controller.
  -HSDL is just a interface to transport PCIe lanes externally, so you could, in theory, connect it to an SAS controller.
  
  What booting limitations exist? Is a RAID driver needed for the controller inside the IBIS drive?
  -Yes, you need a RAID driver for the SiI 3124.
  
  Are the individual SSD controllers connected to the drive's internal RAID controller seen by the operating system or BIOS? (I'd guess 'no' but not explicitly stated.)
  -Neither, they only see the SiI 3124 SATA RAID controller.
  
  Is the RAID controller on the drive seen as a PCI-E device?
  -Probably.
  
  Is the single port host card seen by the system's operating system or is entirely passive?
  -Passive, the card just pipes the PCIe lanes to the SATA controller.
  
  Is the four HDSL port card seen differently?
  -Vaporware at this point - I would guess it is a PCIe x16 to four PCIe x4 switch.
  
  Does the SAS cabling handle PCI-E 3.0 signaling?
  -The current card and half-meter cable are PCIe 1.1 only at this point. The x16 card is likely a PCIe 2.0 switch to four PCIe x4 HDSLs. PCIe 3.0 will share essentially the same electrical characteristics as PCIe 2.0, but it doesn't matter since you'd need a new card with a PCIe 3.0 switch and a new IBIS with a PCIe 3.0 SATA controller anyway.
  
  Is OCZ working on a native HDSL controller that'll convert PCI-E to ONFI? Would such a chip be seen as a regular old IDE device for easy OS installation and support for legacy systems? Would such a chip be able to support TRIM?
  That's something I'd love to see and it would "do away with SATA as a final drive interface", but I expect it to come from Intel and not somebody reboxing old tech (OCZ).