This article describes possible reason why SRX1500 might reboot automatically.

On Junos SRX1500 platforms, in a rare case scenario, if linux watchdogd is struck due to SSD(solid-state drives) IO operations, it causes the router to reboot.

The below logs could be seen during the issue.

 "SSD failure detected, system is going to reboot!!"

This issue might be seen if the following conditions are met:

* On SRX1500 platforms
* SSD operations causing linux watchdogd struck

To resolve this issue upgrade to below versions or above:

junos:22.2R3-S6 junos:22.4R3-S6 junos:23.2R2-S3 junos:23.4R2-S4 junos:24.2R2 junos:24.4R1 junos:24.4R2 junos:25.1R1