my DS run over night now and I took a look at the LCC-values this morning:
for the three "00KA9"-disks the value increased by 2 (from 45 to 47) but for the "22KA9"-disk the timer increased by 223 (from 2082 to 2305). This is still much less increasment then before my modifications yesterday evening, but still to much for my taste.
Especially very interesting is the differrent behaviour of the two disk-types although the same settings have been applied! They seem to handle their timers different.
I then activated the hdparm - script and set the PowerManagement of the drives to disabled (value "255"); the drives settings where "128" before, that means "medium".
I created a "S99hdparmboot.sh" and used this script:
/usr/syno/bin/hdparm -B255 /dev/sda
/usr/syno/bin/hdparm -B255 /dev/sdb
/usr/syno/bin/hdparm -B255 /dev/sdc
/usr/syno/bin/hdparm -B255 /dev/sdd
The script reportet, that the PowerManagement has been turned off for all four drives.
Now I will check the LCC-counter again this evening to see, if it still increases.
Of course I still want to find a timer-value for the "22KA9"-disk that leeds to the longest possible timer-setting working for this drive-type, but that probably will take hours of testing... I am not sure if it is worth it, when the hdparm-setting will do the trick.
We will see this evening