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SRX100 Services Gateway Boot Devices and Dual-Root Partitioning Scheme


This topic includes the following sections:

Boot Devices

The SRX100 Services Gateway can boot from the following storage media (in the order of priority):

  • Internal NAND Flash (default; always present)

  • USB storage key (alternate)

Dual-Root Partitioning Scheme

Dual-root partitions allow the SRX100 Services Gateways to remain functional if there is file system corruption and facilitate easy recovery of the corrupted file system.

The dual-root partitioning scheme keeps the primary and backup Junos OS images in two independently bootable root partitions. If the primary root partition becomes corrupted, the system will be able to boot from the backup Junos OS image located in the other root partition and remain fully functional.

When the SRX100 Services Gateway powers up, it tries to boot the Junos OS from the default storage media. If the device fails to boot from the default storage media, it tries to boot from the alternate storage media. With the dual-root partitioning scheme, the SRX100 Services Gateway first tries to boot the Junos OS 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 device tries to boot from the next available type of storage media. The SRX100 Services Gateway remains fully functional even if it boots the Junos OS from the backup root partition of storage media.


SRX Series devices that ship from the factory with Junos OS Release 10.0 are formatted with the dual-root partitioning scheme.

The SRX100 Services Gateways that are running Junos OS Release 9.6 or earlier use the single-root partitioning scheme. While upgrading these devices to Junos OS Release 10.0, you can choose to format the storage media with dual-root partitions (strongly recommended) or retain the existing single-root partitioning.

For instructions on upgrading to Junos OS Release 10.0, see the following topics: