1 alarms currently active Alarm time Class Description
2011-02-17 05:48:49 PST Minor Host 0 Boot from backup root 查看加载路径：
root> show system storage partitions fpc0:
-------------------------------------------------------------------------- Boot Media: internal (da0) Active Partition: da0s1a
Backup Partition: da0s2a <-- this is the backup slice
Currently booted from: backup (da0s2a) <-- shows booted from that slice
Partitions information: Partition Size Mountpoint s1a 184M altroot s2a 184M / s3d 369M /var/tmp s3e 123M /var s4d 62M /config
s4e unused (backup config)
root> show system snapshot media internal
Information for snapshot on internal (/dev/da0s1a) (primary) Creation date: Feb 24 11:32:07 2012 JUNOS version on snapshot: jbase : 10.4I20120224_1123_bshekar jcrypto-ex: 10.4I20120224_1123_bshekar jdocs-ex: 10.4I20120224_1123_bshekar jkernel-ex: 10.4I20120224_1123_bshekar jroute-ex: 10.4I20120224_1123_bshekar jswitch-ex: 10.4I20120224_1123_bshekar jweb-ex: 10.4I20120224_1123_bshekar jpfe-ex42x: 10.4I20120224_1123_bshekar
Information for snapshot on internal (/dev/da0s2a) (backup) <-- provides info for this slice/partition the switch booted off of and the date the file system was created
Creation date: Feb 14 05:42:42 2012 <-- if less than alarm date then customer should snapshot (it is a good way to confirm JUNOS version on snapshot: jbase : 11.2-20120214.0 jcrypto-ex: 11.2-20120214.0 jdocs-ex: 11.2-20120214.0 jkernel-ex: 11.2-20120214.0
jroute-ex: 11.2-20120214.0 jswitch-ex: 11.2-20120214.0 jweb-ex: 11.2-20120214.0 jpfe-ex42x: 11.2-20120214.0 解决办法：
把备用junos镜像copy到主用junos镜像
request system snapshot media internal slice alternate 查看junos启动镜像
show system storage partitions 确保开机启用主用junos镜像命令：
request system reboot slice alternate media internal user@switch>show system snapshot media internal slice 1 user@switch>show system snapshot media internal slice 2