SRX650 devices boot from the following storage media (in order of priority):
1.
Internal CompactFlash card (default; always present)
2.
External CompactFlash card (alternate)
3.
USB storage device (alternate)
With the dual-root partitioning scheme, the SRX Series device first tries to boot the
JUNOS Software from the primary root partition and then from the backup root
partition on the default storage media. If both primary and backup root partitions of
a media fail to boot, then the SRX Series device tries to boot from the next available
type of storage media. The SRX Series device remains fully functional even if it boots
the JUNOS Software from the backup root partition of storage media.
Important Differences Between Single-Root and Dual-Root Partitioning Schemes
Note the following important differences in how SRX Series devices use the two types
of partitioning systems.
■
With the single-root partitioning scheme, there is one root partition that contains
both the primary and backup JUNOS Software images. With the dual-root
partitioning scheme, the primary and backup copies of JUNOS Software are in
different partitions. The partition containing the backup copy is mounted only
when required.
■
With the dual-root partitioning scheme, when the
request system software add
command is performed for a JUNOS Software package, the contents of the other
root partition are erased. The contents of the other root partition will not be valid
unless the installation is completed successfully.
■
With the dual-root partitioning scheme, after a new JUNOS Software image is
installed, add-on packages like
jais
or
jfirmware
should be reinstalled as required.
■
With the dual-root partitioning scheme, the
request system software rollback
CLI
command does not delete the current JUNOS Software image. It is possible to
switch back to the image by issuing the rollback command again.
■
With the dual-root partitioning scheme, the
request system software delete-backup
CLI command does not take any action. The JUNOS Software image in the other
root partition will not be deleted.
Upgrade Methods
SRX Series devices that ship from the factory with JUNOS Release 10.10 are formatted
with the dual-root partitioning scheme.
Existing SRX Series devices that are running JUNOS Release 9.6 or earlier use the
single-root partitioning scheme. While upgrading these routers to JUNOS Release
10.1, you can choose to format the storage media with dual-root partitions (strongly
recommended) or retain the existing single-root partitioning.
Certain JUNOS Software upgrade methods format the internal media before
installation, whereas other methods do not. To install JUNOS Release 10.1 with the
dual-root partitioning scheme, you must use an upgrade method that formats the
internal media before installation.
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■
Dual-Root Partitioning Scheme Documentation for SRX Series Services Gateways
JUNOS 10.1 Software Release Notes