Here is a list of supported cables, and the part number for the cable. It looks like supported lengths are from 0.5m - 10m.  SFP+ passive direct attach:  • K585N – 1m cable, Molex 74752-9093,   • J564N – 3m cable, Molex 74752-9094,   • H603N – 5m cable, Molex 74752-9096,   • G840N – 7m cable, Molex 74752-9098,   • R620M - 0.5m cable, Molex 74752-1051,   • G692K - 1m cable, Molex 74752-1101,   • P540M - 2m cable, Molex 74752-1201,   • Y984J - 3m cable, Molex 74752-2301,   • N651M - 4m cable, Molex 74752-2401,   • C855K - 5m cable, Molex 74752-3501,   • R4C0V - 1m cable, Molex 74752- , DELL   • 2CM32 - 3m cable, Molex 74752- , DELL   • 337MK - 5m cable, Molex 74752- , DELL   • V15WR - 7m cable, Molex 74752- , DELL   • C4DD6 - 10m cable, Molex 74752- , DELL  Hope this information helps. Thanks.
I am wondering if the SFP+ direct attach cable requirements for the PowerConnect 5524 are posted somewhere.  I am trying to connect this switch to an Intel X520-DA2 dual 10GBE card that is attached to a Synology RS3412xs.  A 1m cable length should be all that is needed.
5524 SFP+ direct attach cable requirements