Fan Alarm observed on Juniper J Series Router- Juniper J4350

Issue: Fan Alarm observed on Juniper J Series Router- Juniper J4350.

We have observed alarms of Fan at router chassis not CPU, sometimes Fan 0 went to "check" state and Fan 1 spin at high spineed and vice-versa.

Troubleshooting Steps:

We have checked RSI(request Support Information) and show log command outputs from router.

After analysis of  RSI provided, The fan failure messages and it gets cleared as well. as per PR797706 <https://gnats.juniper.net/web/default/797706> this has been reported as a bug and suggests an upgrade to 11.4R5-S1 11.4R6 12.1R4 12.1X44-D10.

In order to upgrade to any version greater than 10.4, the flash and RAM has to be 1GB. 

Now you have 1Gb of RAM

root@J4350> show chassis routing-engine

    DRAM                      1024 MB

but only 512Mb of Flash, you need to upgrade to 1Gb

root@haryana_PE2_J4350> show system storage

Filesystem              Size       Used      Avail  Capacity   Mounted on

/dev/ad0s1a             432M       104M       323M       24%  /

The following is the link which would help you understand the same:

<http://kb.juniper.net/InfoCenter/index?page=content&id=TSB15606>