十万火急！请大家帮忙！！！

[dlinger]

aix的机器上oracle901。
目前的状况是：突然所有的连接都断了，jdbc新的连接加不上，从客户端sqlplus连server，查看listener.log，发现连接已经建立了，但是不返回，sqlplus连server没有反应，但也不报错。server端用sqlplus连（没有配tns），不带连接串，可以连上数据库。从客户端tnsping可以通。
服务器配置是8g内存，只跑一个oracle，这是一些参数，各位大侠指点一下看有没有什么问题：
processes = 800
timed_statistics = TRUE
shared_pool_size = 318767104
large_pool_size = 209715200
java_pool_size = 117440512
resource_manager_plan = SYSTEM_PLAN
control_files = /oradata/htcwdb/control01.ctl, /oradata/htcwdb/control02.ctl, /oradata/htcwdb/control03.ctl
db_block_size = 8192
db_cache_size = 1392508928
compatible = 9.0.0
log_archive_start = TRUE
log_archive_dest_1 = LOCATION=/oradata/htcwdb/archive
log_archive_max_processes= 3
log_archive_format = %t_%s.dbf
log_buffer = 1024000
fast_start_mttr_target = 300
undo_management = AUTO
undo_tablespace = UNDOTBS
remote_login_passwordfile= EXCLUSIVE
db_domain =
instance_name = htcwdb
dispatchers = (PROTOCOL=TCP)(SER=MODOSE), (PROTOCOL=TCP)(PRE=oracle.aurora.server.GiopServer), (PROTOCOL=TCP)(PRE=oracle.aurora.server.SGiopServer)
cursor_sharing = FORCE
background_dump_dest = /oracle/app/oracle/admin/htcwdb/bdump
user_dump_dest = /oracle/app/oracle/admin/htcwdb/udump
core_dump_dest = /oracle/app/oracle/admin/htcwdb/cdump
sort_area_size = 52428800
db_name = htcwdb
open_cursors = 1500