Need to get logs from ex series

[vikingo]

If you read my latest post you know what I am talkung about.
I need to retrieve ALL the info from las t week from my IDF´s in order to get some forensics so I can get the cause why dropped a vlan in ALL idf´s in my LAN.

So I need a little help with some CLI commands or junos

Environment.

10 IDF´s “,ade of” 3 to 10 sw each.
one of then is the CORE who mnanages de fiber abd the rest of sw in l2 mode
So I need to FIND why yesterday ONE and ONLY one VLAN crashed in ALL idf´s

Help please??

thanks a lot