mongod segfaults as seen in the log snippet:

Dec 19 14:26:49 abrt[3665]: Saved core dump of pid 24104 (/usr/bin/mongod) to /var/spool/abrt/ccpp-2012-12-19-14:26:38-24104 (1784872960 bytes)
Dec 19 14:26:49 abrtd: Directory 'ccpp-2012-12-19-14:26:38-24104' creation detected
Dec 19 14:26:50 abrtd: Package 'mongo-10gen-server' isn't signed with proper key
Dec 19 14:26:50 abrtd: 'post-create' on '/var/spool/abrt/ccpp-2012-12-19-14:26:38-24104' exited with 1
Dec 19 14:26:50 abrtd: Corrupted or bad directory /var/spool/abrt/ccpp-2012-12-19-14:26:38-24104, deleting

Around this time a number of issues and errors are seen in mongod.log which should have recovered and could be caused by possible issues in AWS or mongod itself we are currently unsure so hints here would also be great.