Customer found out that chassisd log was filled up with the same log generated every 5 seconds and was concerned whether the log suggested any possible service impact. 

A PR addressing this issue was published. It was confirmed harmless, and a fix was made and released.

The same log is generated every 5 seconds in the chassisd log file as below. 

root@QFX10008> show log chassisd
Jun 21 10:46:03 CHASSISD_UTIL_RW_ERR: Cannot read hw.chassis.startup_time value: m
Jun 21 10:46:08 CHASSISD_UTIL_RW_ERR: Cannot read hw.chassis.startup_time value: m
Jun 21 10:46:13 CHASSISD_UTIL_RW_ERR: Cannot read hw.chassis.startup_time value: m
Jun 21 10:46:18 CHASSISD_UTIL_RW_ERR: Cannot read hw.chassis.startup_time value: m
--snip--

The issue was addressed in PR1603588. Refer to the PR for fixed releases. 

The log is generated because the system is calling a module that is not present in QFX10008. 
It is a cosmetic issue and harmless, so it can be safely ignored. 
In order to save log space and keep important logs from being rolled out, applying a syslog filtering configuration to exclude that log is highly recommended.

set system syslog file chassisd match "!(.*CHASSISD_UTIL_RW_ERR: Cannot read.*)"