LSI SAS and sata port multipliers

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kharan5876

Limp Gawd
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Oct 3, 2007
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I have a disk array that uses 2 5-1esata port multipliers.
http://www.addonics.com/products/host_controller/ad5sapm-e.asp

I was looking at Lsi's SAS3801E:
http://www.lsi.com/storage_home/products_home/host_bus_adapters/sas_hbas/lsisas3801e/index.html

My question is this, if I got this host bus adapter, with a SAS to esata fan out cable like this one:
http://eshop.macsales.com/item/Highpoint Technologies/MS1MES/
and hooked it up to my port multipliers. Would everything just work? Do these SAS cards support the SATA port multiplier spec? Is this something that would depend on driver support?

Thanks.
 
Well before i give advice on this, what exactly are you trying to do? your post leaves me a little confused.
How many drives, what type?
Where are the drives enclosed?
Are you trying to make a single volume?

Gimme some more information so i can help you better
 
Sorry I guess that was a big vague.

Right now I have 5x500gb SATA drives, Later I plan to get an additional 5x 750gb drives. The enclosure is actually a scsi jbod that I gutted the scsi stuff out of. My esata port multiplier bridge boards are attached to the back of the jbod.

As far as hardware is concerned I am not doing any raid. I just want it to be a dumb jbod. I will be doing software raid 5 with either zfs or linux raid (mdadm).

I just want to know if all the hardware will work together so that I can see all of my separate disks in the OS. The operating systems I am considering using are Linux, opensolaris, or freebsd.
 
That sounds like it would it work but i would make sure that all the individual componets work with linux, etc. That quite a way to do things.
 
But are you absolutely sure the SAS card will work with the port multipliers? (Not considering OS driver issues)

That is the real issue at hand. I am gonna try to get ahold of their tech support.
 
Have you considered getting some sas backplanes and throwing them in a case like that? You could still use sata.
 
That particular model requires an Interposer, which is not a fan-out. There is actual logic in an Interposer.
 
So I can only connect that SAS card to another card (expander, interposer, whatever) that has some sort of logic? Direct connect to drives wont work?
 
A SAS controller can be connected directly to any SAS or SATA drive.

However that LSI SAS controller cannot be used with SATA port multipliers.

A better setup for what you are doing would probably be to use a SAS expander talk to many drives in an enclosure. You'd end up with *much* better performance using an expander on a SAS controller versus a port multiplier with a SATA controller. This is due to how the SATA protocol works -- with a SAS expander, the controller can do transfers with several drives at a time, but with port multiplexer, only one drive can actively use the link at a time.

The SATA protocol along with how SATA port multiplexers are implemented do not allow for very efficient sharing of the link bandwidth. SAS expanders can handle this sort of set up very efficiently, however.
 
I have looked all over for just a SAS expander, similar to those esata port multiplier bridgeboards that I have.

Everywhere I look you have to buy a whole enclosure. I would like to use the enclosure I already have and not shell out 4 figures for another one. Has anybody seen separate SAS expanders out there or have any recommendations?
 
That would be absolutley perfect, I could probably just take the pci backet, drill some holes in it and attach the card to the jbod. Gotta find out how to get my hands on one now.

Thanks for the advice everyone
 
Just in case anyone is interested. I called Chenbro and they told me these cards are not ready yet, they are still being manufactured in Taiwan. They said that the cards should be available in about 2 months.
 
So far I have been only able to find this model. Unfortunately, I cannot find CK202. There are several re-sellers that sell this card, but I noticed most of them have to place the order with the China manufacturer so lead time can be 6 weeks.

I placed another order with another vendor. If you guys wait, I'll let you know how this turns out and see if I get the card before you rush out and get them.

Of course, you could always shell out for Adaptec's 5 series. With 24 internal and 4 external drives I think that will satisfy us for a while. (its only...cough, $1600!) What's interesting though is the card looks similar to the $300 from Chenbro which is a 16 internal drive.

If any one else has a SEPERATE SAS expander that is not a RAID card let us know. All we want is the expander card that can go to SAS/SATA drives. How hard is this for them to understand without building it into a chassis?

my 2 cents and change...

Andy
 
andrewn2008 said:
If any one else has a SEPERATE SAS expander that is not a RAID card let us know. All we want is the expander card that can go to SAS/SATA drives.
Click to expand...

We have hundreds of them at work... Just standalone boards with a power connector and all the SAS/SATA connectors. Unfortunately, they are for validation/evaluation only and are not a product that my employer sells. I wish we would, but I can see how small that market is compared to selling them just as ICs that OEMs put in their own designs.
 
UICompE02 said:
I'm confused by this statement, can you explain what you mean?
Click to expand...

Okay. You know the basics of SAS and SCSI I hope. (Frequently, people do not have a clue. Like why LVD is not LVD/SE is not HVD is not Ultra3.) You also need to know advanced Fiber Channel.

SAS operates similar to FC, where a target device or host has a WWPN (World Wide Public Name.) Each device has it's own unique WWPN. SATA does not provide a WWPN or any mechanism for a WWPN. An Interposer translates a blind SATA target into a named WWPN target. This is the requirement for mixing SATA and SAS on the same controller or bus. Understand, the WWPN requirement goes around with a direct attachment, but returns with multi-port SATA (e.g. IBM EDDM) or anything which may interfere with the "direct" connection, very specifically multi-lane connectors.
 
AreEss said:
You know the basics of SAS and SCSI I hope.
Click to expand...
Oh, very much so. ;)
SAS operates similar to FC, where a target device or host has a WWPN (World Wide Public Name.) Each device has it's own unique WWPN. SATA does not provide a WWPN or any mechanism for a WWPN. An Interposer translates a blind SATA target into a named WWPN target. This is the requirement for mixing SATA and SAS on the same controller or bus. Understand, the WWPN requirement goes around with a direct attachment, but returns with multi-port SATA (e.g. IBM EDDM) or anything which may interfere with the "direct" connection, very specifically multi-lane connectors.
Click to expand...

You don't need an interposer to either directly connect a SATA drive to a controller or a SATA drive to an expander.

In the case of directly attaching to the controller, well, there's only one thing that link can talk to so the WWID problem goes away.

When you have a SATA drive hanging on the end of an expander port, what happens is that the expander has inside of it what is called an STP target (SATA Tunneling Protocol) with its own WWID that the expander manufacturer assigns. The controller talks to the STP target, and the STP target within the expander talks to the SATA drive.

I guess you may be referring to when you would like to set up a dual-port connection to a SATA drive, and yes, in that case some sort of logic is required since the SATA drive only has one physical port on it. In that case, something like an Active-Active Mux or the like is used.

I don't know what you mean by multi-lane connectors in this case since you will never have more than one lane going to a SATA drive...
 
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