Straight Dope: 8087 - 4 SAS/SATA

W

Wolf-R1

[H]ard|Gawd
Joined
Aug 30, 2004
Messages
2,005
Alright I cannot get a straight answer from either 3Ware or Tyan.
I am looking to purchase a 9690SA RAID controller from 3Ware who tells me that the 8087 to discrete forward breakout cable will not do SAS.

However the tech at Tyan told me they use them in their chassis all the time where their backplanes have discrete connections rather than a single 8087 connector.

So who's right? Does anyone have any info on this? Optionally can someone recommend a 2U chassis that supports the 8087 link, 6+ HDD slots, and room for a decent server class mobo?
 
Wolf-R1 said:
Alright I cannot get a straight answer from either 3Ware or Tyan.
I am looking to purchase a 9690SA RAID controller from 3Ware who tells me that the 8087 to discrete forward breakout cable will not do SAS.
Click to expand...
You need a breakout cable with power. The reason is that the SFF8482 connectors on the drives have a bridge between the power and data portions of the connectors, preventing you from plugging SAS disks into sata controllers. So the cable pissboy linked should work, but a breakout cable lacking power connections wouldn't, because you physically can't plug the drives into the cables.
Wolf-R1 said:
However the tech at Tyan told me they use them in their chassis all the time where their backplanes have discrete connections rather than a single 8087 connector.

So who's right? Does anyone have any info on this? Optionally can someone recommend a 2U chassis that supports the 8087 link, 6+ HDD slots, and room for a decent server class mobo?
Click to expand...
Both are right; the Tyan backplane passes the sata-shaped connection through to SAS-shaped drive ports.

I like the Supermicro 8x6 series myself; they contain a SAS expander so you can plug 12 drives in with one 8087 cable. They're noisy, but if this is going in a machine room that's not a concern and they make up for the noise by staying cool. Note that if you plan to expand (no pun intended) in the future, the 846e1 is only about $300 more and has twice the capacity.
 
unhappy_mage said:
You need a breakout cable with power. The reason is that the SFF8482 connectors on the drives have a bridge between the power and data portions of the connectors, preventing you from plugging SAS disks into sata controllers. So the cable pissboy linked should work, but a breakout cable lacking power connections wouldn't, because you physically can't plug the drives into the cables.

Both are right; the Tyan backplane passes the sata-shaped connection through to SAS-shaped drive ports.

I like the Supermicro 8x6 series myself; they contain a SAS expander so you can plug 12 drives in with one 8087 cable. They're noisy, but if this is going in a machine room that's not a concern and they make up for the noise by staying cool. Note that if you plan to expand (no pun intended) in the future, the 846e1 is only about $300 more and has twice the capacity.
Click to expand...

Pertaining to the breakout cable with power: understand if you're plugging straight into the drive. However in this case it would be going into a backplane which would be powered otherwise. Is this still a necessary evil then? For a cable with a powered connection? That doesn't make sense to me as I would assume that the backplane would provide the necessary power connections and all the breakout cable is doing is providing data connections. Is this assertion not correct?

As to that Supermicro solution, way too may drive positions. Ideally I actually just need 6-8 but if the price is right I may not argue. And yes it's going into a dedicated server room. Noise is not a concern as this is for a business.
 
Wolf-R1 said:
Pertaining to the breakout cable with power: understand if you're plugging straight into the drive. However in this case it would be going into a backplane which would be powered otherwise. Is this still a necessary evil then? For a cable with a powered connection? That doesn't make sense to me as I would assume that the backplane would provide the necessary power connections and all the breakout cable is doing is providing data connections. Is this assertion not correct?

As to that Supermicro solution, way too may drive positions. Ideally I actually just need 6-8 but if the price is right I may not argue. And yes it's going into a dedicated server room. Noise is not a concern as this is for a business.
Click to expand...

You only need the combo power/sas cable when you are plugging in straight to drives or if you have a dummy backplane with no other power sources. Self powered backplanes will not require this function to work, in this event, you simply need the normal sas breakout cables.
 
Thus all I have to do is verify that the backplane on any system is powered...

Awesome. Thanks for all the help.
 
Wolf-R1 said:
Pertaining to the breakout cable with power: understand if you're plugging straight into the drive. However in this case it would be going into a backplane which would be powered otherwise. Is this still a necessary evil then? For a cable with a powered connection? That doesn't make sense to me as I would assume that the backplane would provide the necessary power connections and all the breakout cable is doing is providing data connections. Is this assertion not correct?
Click to expand...
You could use a plain splitter cable if you're going into a backplane.
Wolf-R1 said:
As to that Supermicro solution, way too may drive positions. Ideally I actually just need 6-8 but if the price is right I may not argue. And yes it's going into a dedicated server room. Noise is not a concern as this is for a business.
Click to expand...
It's about $860 for the case and power supply from Next International. I haven't dealt with them before, so it might behoove you to do your own searching and find somewhere you're comfortable with.
 
You must log in or register to reply here.
Back
Top