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FAS2020 and DS14MK2 Mis-cabled

 

 

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stephen.stocke at iconsultci

Apr 24, 2012, 8:58 AM

Post #1 of 3 (1306 views)
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FAS2020 and DS14MK2 Mis-cabled

Hello Toasters

I have a FAS2020 Active/Active system with one DS14MK2-AT shelf attached. This weekend I intend to hot-add an additional DS14MK2-AT shelf. However, I believe the existing loop is cabled incorrectly. I'm hoping someone on this list can give me some pointers to confirm whether the cabling can be corrected without taking the filers offline. I really want to fix the cabling before I attempt to hot-add the new shelf. The current cabling is:

CNTRL-A/0a -> AT-FCX-A -> CNTRL-A/0b
And
CNTRL-B/0a -> AT-FCX-B -> CNTRL-B/0b

According to the FAS2020 installation flyer, the end of each loop path should terminate with the opposite controller's 0b port (not the same controller as above). Is it possible/advisable to disconnect the cable from both controllers' 0b port and swap them over to get to the correct setup? So long as I don't lose one of the AT-FCX modules during the switchover it seems like it would be okay.

I'm going to open a case with support but I was hoping some of the experts on this list might have some thoughts/recommendations/horror stories you can share?

Thanks
Steve

DISCLAIMER: The information contained within this electronic mail is confidential and may be legally privileged and it is intended for the addressees only. If you have received this message in error and you are not the intended recipient please notify the sender immediately and delete the message. Any review of the contents, dissemination or distribution of such, copying or other use of this communication or the information within is strictly prohibited. For further information or should you wish to discuss this with us, please email legal [at] iconsultci

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jeff.cleverley at avagotech

Apr 24, 2012, 9:11 AM

Post #2 of 3 (1238 views)
Permalink
Re: FAS2020 and DS14MK2 Mis-cabled [In reply to]

Steve,

I don't have a 2020 and don't know if it has any special quirks, but
swapping your B cables live should not be an issue. Both heads will
still have access to the shelf via the A ports. I've done this type
of swap on 6000 series boxes on several occasions when I've had
cabling issues.

Jeff

On Tue, Apr 24, 2012 at 9:58 AM, Stephen Stocke
<stephen.stocke [at] iconsultci> wrote:
> Hello Toasters
>
> I have a FAS2020 Active/Active system with one DS14MK2-AT shelf attached.  This weekend I intend to hot-add an additional DS14MK2-AT shelf. However, I believe the existing loop is cabled incorrectly.  I'm hoping someone on this list can give me some pointers to confirm whether the cabling can be corrected without taking the filers offline.  I really want to fix the cabling before I attempt to hot-add the new shelf.  The current cabling is:
>
> CNTRL-A/0a -> AT-FCX-A -> CNTRL-A/0b
> And
> CNTRL-B/0a -> AT-FCX-B -> CNTRL-B/0b
>
> According to the FAS2020 installation flyer, the end of each loop path should terminate with the opposite controller's 0b port (not the same controller as above).  Is it possible/advisable to disconnect the cable from both controllers' 0b port and swap them over to get to the correct setup?  So long as I don't lose one of the AT-FCX modules during the switchover it seems like it would be okay.
>
> I'm going to open a case with support but I was hoping some of the experts on this list might have some thoughts/recommendations/horror stories you can share?
>
> Thanks
> Steve
>
> DISCLAIMER: The information contained within this electronic mail is confidential and may be legally privileged and it is intended for the addressees only.  If you have received this message in error and you are not the intended recipient please notify the sender immediately and delete the message.  Any review of the contents, dissemination or distribution of such, copying or other use of this communication or the information within is strictly prohibited.  For further information or should you wish to discuss this with us, please email legal [at] iconsultci
>
> _______________________________________________
> Toasters mailing list
> Toasters [at] teaparty
> http://www.teaparty.net/mailman/listinfo/toasters



--
Jeff Cleverley
Unix Systems Administrator
4380 Ziegler Road
Fort Collins, Colorado 80525
970-288-4611

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filip.sneppe at gmail

Apr 24, 2012, 1:39 PM

Post #3 of 3 (1242 views)
Permalink
Re: FAS2020 and DS14MK2 Mis-cabled [In reply to]

Hi Steve,

Yes this type of recabling should work without any problems provided you always
leave one path for each controller to the shelves. Prepare to get a
console message
about the failed redundancy when you pull one cable. This may also trigger
an ASUP depending on how the relevant option is set.

Hint: use the "storage show disk -p" command to check your multipathing
before, during and after your changes. You should give the filer about
30 seconds
after a change before it will typically start to use newly added paths.

The problem with your current cabling setup is that, while it is technically
a redundant cabling solution, a failure of one of your shelf modules will result
in one controller being unable to see the shelf. If this controller is
serving the
data on that shelf, it will panic.

Best regards,
Filip

On 4/24/12, Jeff Cleverley <jeff.cleverley [at] avagotech> wrote:
> Steve,
>
> I don't have a 2020 and don't know if it has any special quirks, but
> swapping your B cables live should not be an issue. Both heads will
> still have access to the shelf via the A ports. I've done this type
> of swap on 6000 series boxes on several occasions when I've had
> cabling issues.
>
> Jeff
>
> On Tue, Apr 24, 2012 at 9:58 AM, Stephen Stocke
> <stephen.stocke [at] iconsultci> wrote:
>> Hello Toasters
>>
>> I have a FAS2020 Active/Active system with one DS14MK2-AT shelf attached.
>> This weekend I intend to hot-add an additional DS14MK2-AT shelf. However,
>> I believe the existing loop is cabled incorrectly. I'm hoping someone on
>> this list can give me some pointers to confirm whether the cabling can be
>> corrected without taking the filers offline. I really want to fix the
>> cabling before I attempt to hot-add the new shelf. The current cabling
>> is:
>>
>> CNTRL-A/0a -> AT-FCX-A -> CNTRL-A/0b
>> And
>> CNTRL-B/0a -> AT-FCX-B -> CNTRL-B/0b
>>
>> According to the FAS2020 installation flyer, the end of each loop path
>> should terminate with the opposite controller's 0b port (not the same
>> controller as above). Is it possible/advisable to disconnect the cable
>> from both controllers' 0b port and swap them over to get to the correct
>> setup? So long as I don't lose one of the AT-FCX modules during the
>> switchover it seems like it would be okay.
>>
>> I'm going to open a case with support but I was hoping some of the experts
>> on this list might have some thoughts/recommendations/horror stories you
>> can share?
>>
>> Thanks
>> Steve
>>
>> DISCLAIMER: The information contained within this electronic mail is
>> confidential and may be legally privileged and it is intended for the
>> addressees only. If you have received this message in error and you are
>> not the intended recipient please notify the sender immediately and delete
>> the message. Any review of the contents, dissemination or distribution of
>> such, copying or other use of this communication or the information within
>> is strictly prohibited. For further information or should you wish to
>> discuss this with us, please email legal [at] iconsultci
>>
>> _______________________________________________
>> Toasters mailing list
>> Toasters [at] teaparty
>> http://www.teaparty.net/mailman/listinfo/toasters
>
>
>
> --
> Jeff Cleverley
> Unix Systems Administrator
> 4380 Ziegler Road
> Fort Collins, Colorado 80525
> 970-288-4611
>
> _______________________________________________
> Toasters mailing list
> Toasters [at] teaparty
> http://www.teaparty.net/mailman/listinfo/toasters
>
_______________________________________________
Toasters mailing list
Toasters [at] teaparty
http://www.teaparty.net/mailman/listinfo/toasters

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