This article describes the issue of the MX-style chassis, such as SRX5800 or MX960, receiving the Top Fan Tray 0 i2c backup not ok, status 0x8 failed 1 times log message.
To identify if the Top Fan Tray 0 i2c backup not ok, status 0x8 failed 1 times log is harmful or not.
Your chassis is placed in the perfect (recommended) temperature conditions; but still generates the following log:
Top Fan Tray 0 i2c slave not ok, status 0x8 failed 1 times
show chassis temperature-thresholds
2021-03-19: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives.