I believe I have a very similar problem…
I have two EX4100 stacked
The bottom EX4100 shows 28C and has a fan speed of 1935 rpm
The top EX4100 shows 38C and has 618 rpm fan speed
I have never had a problem like that before
it happened hours after upgrading to OS5
First after upgrading to OS5, I had a failing drive - Drive SMART Failure
Drive status FAULT
RAID status degraded
I submitted the disk to the WD Data Lifeguard Diagnostic tool, and after 30+ hours it had found some bad sectors.
After fixing them, the notice that I need probably to rebuild the drive.
I put the drive back, and booted the EX4100.
First try to rebuilt failed with message
“Volume Rebuild Failed
Volume 1 rebuild has failed. Check the system’s drive status by running Disk Test in Settings / Utilities”
So, I shutdown, removed the drive, and fixed it on my old Windows 7 machine. Just run SMART check with success. I warm inserted the disk back into the EX4100, and after nearly a day the RAID was rebuilt OK.
Today, after boot, the system fan on max speed (1935 rpm), and system showing 28C ( ¿ under temperature ?)
I cannot connect to the web server via browser - refused to connect -
after reboot, everything is normal again -
BUT - after about 30 minutes, the EX4100 running full system check can no longer be accessed (38C/631rpm)
I am starting to DESPAIR…