Hi Jessica.
For the buffered limit you can try :
Increase the buffer size to the max.
limit the logs to the vpn class:
Logging class vpn buffered debugging.
On the other hand you can try the debugs :
Debug crypto condition peer peer_address
debug cry isa 128
debug cry ipsec 128
If you lose the ssh session the debugs will be disabled. Finally for the vpn tunnels usually it goes down due to :
Idle timeout
dead peer detection
delete from other end.
HTH.
