Boot Media and Boot Partition on the SRX Series Services Gateways

When the SRX Series device powers on, it tries to boot the Junos Software 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.

Table 131 provides information on the storage media available on SRX Series devices.

Table 131: Storage Media on SRX Series Devices

SRX Series Devices	Storage Media
SRX100, SRX210, and SRX240	Internal NAND flash (default; always present) USB storage device (alternate)
SRX650	Internal compact flash (default; always present) External flash card (alternate) USB storage device (alternate)

With the dual-root partitioning scheme, the SRX Series device 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 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 OS from the backup root partition of the storage media.