extend SAS cables more than 5 meters

[rojas]

Hi All,

Does anybody know how to extend a 5m SAS cables for disk shelves more than 5 meters?

Thanks very much,

Mauricio

[thomas_glodde]

Hi,

no, it is not possible.

netapp will offer 7m cables in the near future tho.

Regards,

Thomas

[MARTINLEGGATT · Accepted solution]

The Netapp System configurator for the DS4243 shows you can get cables in 0.5m, 2m, 5m, 10m and 20m:

http://support.netapp.com/NOW/knowledge/docs/hardware/NetApp/syscfg/scdot81/index.htm

SAS,QSFP-QSFP,CU,100 OHM,0.5M PN: X6557-R6

SAS,QSFP-QSFP,CU,100 OHM,2M PN: X6558-R6

SAS,QSFP-QSFP,CU,100 OHM,5M PN: X6559-R6

SAS,QSFP-QSFP,CU,100 OHM,10M PN: X6590-R6

SAS,QSFP-QSFP,CU,100 OHM,20M PN: X6591-R6

Assuming your using Ontap 8.1 and the latest shelves.

Regards

Martin

[aborzenkov]

What I have not found so far - is there any limit on total distance from head to shelf. Meaning - can you actually have 10 shelves stack each connected with 20m cable?

[radek_kubka]

Nice question

Each IOM is a SAS switch, right? So I would guess it should be perfectly fine to have 10x 20m hops between shelves.

Still though you need to connect the last shelf in the stack back to the controller, so it  can't be further away than 20m...

Regards,

Radek

[aborzenkov]

Last shelf needs to be connected for dual controller, yes. Single controller does not need it.

And having 10 x 20m cables does not mean having 200m distance. I have seen enough configurations where long cables were ordered "just in case" because at the time of putting it together nobody could say where equipment would be actually located. Then you have to use whatever is available on site. (I remember couple of dozens 50m FC cables between adjacent cabinets. Just to find place to stash them away was the challenge )

And at the end the real question is, would NetApp support it. I have seen mix of FC and SATA shelves in one loop, shelves connected to non-shelf port on FAS270, copper controller-to-shelf connection. It worked

[radek_kubka]

 (I remember couple of dozens 50m FC cables between adjacent cabinets. Just to find place to stash them away was the challenge  )

I hate (too) long cables! I wish we can make them to measure

(actually we used to do that with flat SCSI and ATA cables - just to make the inside of a server / PC look tidy )

[scottgelb]

the 10m and 20m have been on the parts list for a while but not available the last I checked.  I haven't heard of a 7m version of the cable.  But the 10/20 look like they will have their own firmware on the cable so possibly another firmware to update on a system.  Hopefully we get them soon... the Atto bridges are only used for MetroCluster so can't use them to extend length over 5m.