SRX650 Services Gateway Boot Devices and Dual-Root Partitioning Scheme

The SRX650 Services Gateway can 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 key (alternate)

Note: If you explicitly boot the services gateway using the CLI and the services gateway has two USBs installed (one in slot 0 and the second in slot 1), if the USB in slot 0 fails, the booting sequence will not boot from the second USB installed in slot 1. Instead, the device will boot using the next storage media in its storage media booting priority list: Internal CompactFlash card, then External CompactFlash card.

The dual-root partitions allow the SRX650 Services Gateways to remain functional if there is file system corruption and facilitates 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 SRX650 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 SRX650 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 SRX650 Services Gateway remains fully functional even if it boots the Junos OS from the backup root partition of storage media.

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

Existing SRX650 Services Gateway 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 Juniper Networks Junos 10.0 Software Release Notes.