SuperMicro JBOD Question

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CopyRunStart

Limp Gawd
Joined
Apr 3, 2014
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I just received my 847-E16-RJBOD and am a little confused. There are 4 SAS cables but 5 internal SAS ports. 2 in the rear and then 3 in the front. I'm not sure how to hook up the cables. In the front, 2 are grouped together and then 1 is on the side by itself.

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It comes with a manual, telling you your options.

There are many ways to connect it, depend on your goal.
 
Hey Patrick, thank you for responding.

The layout/images in the SM manual don't match my system. It shows 6 SAS ports and they are not located anywhere near how it is on mine.

I'm trying to achieve maximum bandwidth while still eliminating single points of failure.

-21 mirrors.
-1 disk from the mirror connected to the front expander, 1 disk from the mirror connected to the rear expander.
-Front Expander connected to top 2 backplane ports, which are both connected to HBA 1.
-Rear Expander connected to bottom 2 backplane ports, which are both connected to HBA 2.

I'm assuming the 2 internal SAS ports next to the rear are for the rear expander. My only confusion is why there are 3 internal ports in the front. Is one for cascading/daisy chaining other JBOD's?
 
Really, both should have 3 ports. But it matters not, all 3 ports are the same.

What you will want to do is connect two to the front, and two to the back.
Then you will want your two hba's to connect one to each front and back.
This way if an hba fails, you still have access to all disks.
Though, this will require you to setup multipath on your os.

The other option, without multipath, is to set it up as you described. But you will loose half your disks on an hba failure.
 
If I use multipath, will I still be wide-porting in this situation?

I would lose half the disks but not the pool correct? (I realize I'd be just 1 drive failure away from pool failure). I'd obviously prefer the multipathing but I'd also like to be getting 12Gb/s to each HBA.

I should also mention these are SATA disks.
 
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CopyRunStart said:
I would lose half the disks but not the pool correct? (I realize I'd be just 1 drive failure away from pool failure). I'd obviously prefer the multipathing but I'd also like to be getting 12Gb/s to each HBA.
Click to expand...
FYI, I don't think any of Supermicro's 4U solutions offer 12Gb/s backplanes. Only a few of their 2Us do.
 
the E26 would have the backplanes to support multipathing, the E16 just has cascading.
 
TeeJayHoward said:
FYI, I don't think any of Supermicro's 4U solutions offer 12Gb/s backplanes. Only a few of their 2Us do.
Click to expand...

Just to be clear, I didn't mean 12Gb/s. I just meant wideporting. Which I guess would be 6Gb x 4 lanes x 2 cables. I can't find any datasheet that says whether this is supported or not.
 
Any ideas on what I should use the the 3 extra drive slots on the front for? Since I'm using mirrors and the rear expander only has 21 drive slots, I can only use 21 (of 24) in the front. Should I just use them as hot spares? Cold spares?
 
CopyRunStart said:
Any ideas on what I should use the the 3 extra drive slots on the front for? Since I'm using mirrors and the rear expander only has 21 drive slots, I can only use 21 (of 24) in the front. Should I just use them as hot spares? Cold spares?
Click to expand...
Supermicro offers an LCD display which can go in one of the 3.5" slots.
 
That sounds like a good idea.

So based on what was said earlier in the thread, will the 847-E16 be able to "link aggro" two 8088 cables connected to the same HBA?
 
Bought the E26 model. I was suprised to find no internal sff-8087 included to connect the front and back backblanes. This in effect made it two enclosures sharing a chassis. Since we are building an HA setup and will need to cascade, I had to order additional cables. I connected each of the external SFF-8088 to each expander chip, then ran a SFF-8087 from each front expander to a back one. Haven't fired it up yet since the HBAs have not arrived.
 
CopyRunStart said:
That sounds like a good idea.

So based on what was said earlier in the thread, will the 847-E16 be able to "link aggro" two 8088 cables connected to the same HBA?
Click to expand...

I still can't find a definitive answer as to whether the 847-E16 will link aggregate two External SAS connections. Anybody have any ideas?
 
CopyRunStart said:
I still can't find a definitive answer as to whether the 847-E16 will link aggregate two External SAS connections. Anybody have any ideas?
Click to expand...

Already posted above:

"the E26 would have the backplanes to support multipathing, the E16 just has cascading."
 
diehard said:
Already posted above:

"the E26 would have the backplanes to support multipathing, the E16 just has cascading."
Click to expand...

I thought that multi-pathing is different from wide-link, wide-port, or link aggregation. I thought multi-pathing was having redundant connections to a SAS drive?

For instance this post seems to indicate that the E16 can wide-port or channel bond http://hardforum.com/showpost.php?p=1038979186&postcount=3 .
 
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