I've been looking for information regarding this, but there's very little out there. I'm a drive junkie, and trying to find a way to increase efficiency of my system. Right now, I span 14 drives in a JBOD configuration, across 4 on board SataII ports, 3x 4port pci Sata controllers, and 2 on board pata ports. So naturally, a port multiplier has been in my thoughts for quite some time.
I remember when SataII came out, I had heard rumors that one of the new features was supporting up to 15 drives per port, or in other words, a port multiplier was possible in the future. So, I began to monitor and watch the web for these things to pop up.
Unfortunately, this didn't happen as fast as I had hoped. It's been well over a year since I saw them first come out, and still, as far as I can tell, there's only 3-5 different types on the market thus far. So that brings me here.
Has anyone successfully used these for an internal application? They all seem to operate with an eSata interface in mind. What I'm wanting to do, is take the 6 on board SataII ports I have, hook up 6 port multipliers, and be able to connect 30 drives(multipliers I've seen thus far are 1-to-5 port). This would also allow me to confine my wiring catastrophe to the left side of my case, away from the motherboard and video card and such, and free up PCI slots. This is also not a commercial application, this is an in-home end-user application.
there are different kinds of port multipliers. one behaves like ethernet, where you will only be able to write to one drive at a time, but at full speed. the other allows you to divide the bandwidth of 300 MB/sec between any drives on the multipler equally. none is an efficient solution at this moment. buying a serious drive controller is simpler, and better performing depending on the drives and your purpose.... which is not listed in your post.
From what I've read thus far, SataII caps at 375MB/sec, between 5 drives, that's more than fine, since most 7200rpm sata drives aren't much faster than that to begin with. My main goal is storage. I have a ton of dvd's, and instead of creating backups and watching them, I rip them to my local machine, and play back via a media center pc in another room, over the network. So, raw speed isn't the most important thing, my limiting factor is configuration. I'd like to be able to reach 20 drives. My primary computer now has 5 pci slots and a pci-e slot, with one pci slot being covered by an 8800gts, 4 pci slots holding 4 port sata controller cards.
What do you mean by a serious drive controller? The 8 port sata controllers are in the neighborhood of $300-500, and typically require PCI-X, which I don't have.
Cheaper controllers that use chips from Silicon image are widely available, and a certain chip you will find noted in those links you posted earlier is designed for use with port multipliers. Just be aware that the cpu will be doing all of the work.
I have been looking, but have not found any comprehensive list of what SATA controllers work with port multipliers. HOWEVER - its supposed to be a standard that works among all sata ports. Some reports show port multiplied drives will not show up at all on bootup -- until you load the driver in an OS, at which point all become accessible.
Cost is an issue when creating a large storage center. I assume you are using relatively small drives in this case - just stuff you have laying around. Consolidating to less than 14 drives, and replacing them with 1 TB drives at 199 each would leave you with a significant amount of room to grow without needing the expensive raid card.
I'm aware that some controllers will not show at boot, until the OS is loaded and driver is loaded. That's not a problem for me. I'm trying to consolidate 14 500gb drives into a single raid6 volume. Up until now, using JBOD hasn't worked out so great for me, and using multiple controllers it's getting pretty cramped. Unless I can get a port multiplier working, I'm going to be stuck with multiple controllers, which means software raid is my only option. If I can find some port multipliers that work, I'll dump the appropriate money into a good controller card that supports this function, and I can control the array via it.
Don't assume that you can plug a port multiplier into any SATA port and have it work-- you can't. Many controllers, including popular ones, still do not support port multipliers.
And yes, there are two modes: FIS based and Command-based. What is supported is really based on the controller, not the port multiplier-- the port multipliers can work in either mode, but FIS based is more complicated for the controller to support. The difference between the two is that with Command-based, you can only have an outstanding IO request to a single drive, whereas with FIS based, you can have outstanding IO requests to multiple drives at a time. This makes FIS-based much faster, as you can interleave drive requests, instead of issuing them all serially.
I am puting up a dumb server with 5 Sata drives and connecting them via the power from the internal supply and connecting them thru an esat output cable bracket only [problem is I have only 2 ports available on the host computer that is connected via a generic esata raid card that is only Pci and not pci express.Reading thru the above it was mentioned that some multiplexer hubs won't be able to work with them which means if (I buy one thtats incompatable with the multiplexor hub I'll be screwed as I don;t have a pci express slot available
was thinking of purchasing the sata port 5 hub on http://www.cooldrives.com/sahub5muussi.html
but wonder how I can tell if it will work with that card
in addition to what I just wrote I have no idea whether a SAtA II multiplexexor will work with the esata Sata I card I own nor what chipset the esata card uses pleae adress this ASAP not sure what one I may buy willl work with it