Noisy fan after upgrade to OS5

Couple of hours ago I have upgraded my EX2 Ultro to OS5. Since then fan is over 10k rpm and making constant noise… Disks run OK at about 53 - 55 C.
System is > 1 year old.
Why that happens?

Look for « indexing »

This will go on for several days.

It’s “normal” (stupid. . .but normal)

If you are nervous; use supplemental cooling (i.e. another PC fan under the drive)

Thank you for answers. Indeed, after 2 hrs I noted 61% indexing message but later it has gone.
I just ‘hibernated’ for night and since early morning hard work is continuing.
BTW ‘hibernating’ is the only way to stop the device as no power switch exists. Hmmmm
After 1.5 hrs status message is ‘Generating previews…’.
Fan 10714 rpm.
Really, something to do. But accessible for other machines.
My second NAS from QNAP is cold and silent.
Best regards!

yes. . . . the horribly inefficient wd indexing process.

ah yes. . .the total inability to turn “off” the device.

To be clear: hibernate just does a “controlled shutdown”. If power cycles on the plug; (like from a power failure; or a light switch); the unit will fire up and reboot. (so - - - it is CORRECT to say the unit is hibernating; becuase it is not truely off)

FWIW: I would not hibernate the unit while this terrible indexing process is happening; not sure where it will pick back up. . . .it might not be where it was stopped. I would make sure the unit is well ventilated and possibly provide an external fan to keep it cool.

To complete this subject. After about six hours the unit slowly stopped the fan after all indexing and previews ere done and now stays silent, although not ‘cool’. See below:

System Temperature Normal
Drive1 Temperature 54 °C
Drive2 Temperature 51 °C
Fan Speed 0 RPM
Drive Status Healthy
RAID Status Healthy
Thank you for all support!

Those temperatures are normal with the two drive MyClouds.