Inmiddels ook contact gehad met technische suport van Synology.
Deze geven aan dat in de logging te zien is dat twee disks errors geven.
Aangezien ik voornamelijk downloadbare data op mijn schijven had staan heb ik besloten een backup te maken op een PC van de data die ik echt niet kan missen. De andere data kan ik altijd weer downloaden.
Vervolgens hele NAS met de 4 schijven opnieuw te installeren (factory reset).
Uitkomst: Werkend NAS met inderdaad een defecte disk van 500GB.
Deze zal ik asap vervangen.
De reactie van suport was:
Hi HK,
Thank you for contacting Synology support.
From the log, the old disk2 and disk4 have problem now:
[HDD2. Serial Number: WD-WCAZAD033816]
Value1 and Value 198 have value. Value1 is critical to WD disk but not to Seagate disk:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x002f 200 200 051 Pre-fail Always - 75
3 Spin_Up_Time 0x0027 170 166 021 Pre-fail Always - 6458
4 Start_Stop_Count 0x0032 099 099 000 Old_age Always - 1402
5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0
7 Seek_Error_Rate 0x002e 200 200 000 Old_age Always - 0
9 Power_On_Hours 0x0032 092 092 000 Old_age Always - 6146
10 Spin_Retry_Count 0x0032 100 100 000 Old_age Always - 0
11 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 0
12 Power_Cycle_Count 0x0032 099 099 000 Old_age Always - 1045
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 53
193 Load_Cycle_Count 0x0032 140 140 000 Old_age Always - 182371
194 Temperature_Celsius 0x0022 110 106 000 Old_age Always - 40
196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0
197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0
198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 1
199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0
200 Multi_Zone_Error_Rate 0x0008 200 200 000 Old_age Offline - 1
[HDD4. Serial Number: WD-WXF1A20V6242]
HDD4's Value1 has 9:
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x002f 200 200 051 Pre-fail Always - 9
3 Spin_Up_Time 0x0027 186 151 021 Pre-fail Always - 1691
4 Start_Stop_Count 0x0032 001 001 000 Old_age Always - 221358
5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0
7 Seek_Error_Rate 0x002e 100 253 000 Old_age Always - 0
9 Power_On_Hours 0x0032 056 056 000 Old_age Always - 32723
10 Spin_Retry_Count 0x0032 100 100 051 Old_age Always - 0
11 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 828
191 G-Sense_Error_Rate 0x0032 001 001 000 Old_age Always - 485
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 481
193 Load_Cycle_Count 0x0032 001 001 000 Old_age Always - 1211561
194 Temperature_Celsius 0x0022 106 091 000 Old_age Always - 41
196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0
197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0
198 Offline_Uncorrectable 0x0030 100 253 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 40
200 Multi_Zone_Error_Rate 0x0008 200 200 051 Old_age Offline - 0
Based on the current finding, we will suggest to backup data soon as now two old disks have problem. Then please replace them and recreate volume to restore from backup.
Hope this helps.