NAS540 Volume status shows resyncing

nat_ntsb

Hi

I m using NAS540(4 disks, raid5) for years and did not make any change. When I was copying file(SMB) suddenly I could not access my share drive. As I checked, it shown resyncing in Storage Manager > Volume > Volume status.

I don't know why it started to resync, I did not do anything.

I'm not sure the storage is degraded or not. It shows "Storage Status: Warning" at home screen but in Storage Manager > Overview, it shows "Healthy" and Volume on RAID shows no degraded.

I also check S.M.A.R.T and 4 HDD status are green but when I click on Disk3, it shows BAD and Status: Danger with 5 Reallocated_Sector_Ct (detail below)

I m not sure because of DISK 3 or not but the status showing green. Should I change disk3? Can I change it with 1TB disk? (I'm using all 2 TB disk and I only use around 60% of volume, so I m considering to reduce my HDD size.)

ItemValue

Power_On_Hours	8685 hour(s)
Spin_Retry_Count	0
Reallocated_Sector_Ct	5
Model Family	Western Digital Caviar Green (AF)
Device Model	WDC WD20EARS-19MVWB0
Serial Number	WD-WCAZA4120898
LU WWN Device Id	5 0014ee 25ad78d8d
Firmware Version	51.0AB51
User Capacity	2.00 TB
Sector Sizes	512 bytes logical, 4096 bytes physical
ATA Version	ATA8-ACS (minor revision not indicated)
SATA Version	SATA 2.6, 3.0 Gb/s
Local Time	Wed Feb 28 20:06:38 2024 GMT
SMART support	Available - device has SMART capability.
SMART support	Enabled

S.M.A.R.T - Disk3

OverviewS.M.A.R.T InfoIDAttributeValueWorstThresholdTypeUpdatedWhen
FailedRaw Data

1	Raw_Read_Error_Rate	200	200	051	Pre-fail	Always	-	0
3	Spin_Up_Time	243	168	021	Pre-fail	Always	-	2841
4	Start_Stop_Count	099	099	000	Old_age	Always	-	1930
5	Reallocated_Sector_Ct	200	200	140	Pre-fail	Always	-	5
7	Seek_Error_Rate	200	200	000	Old_age	Always	-	0
9	Power_On_Hours	089	089	000	Old_age	Always	-	8685
10	Spin_Retry_Count	100	100	000	Old_age	Always	-	0
11	Calibration_Retry_Count	100	100	000	Old_age	Always	-	0
12	Power_Cycle_Count	100	100	000	Old_age	Always	-	593
192	Power-Off_Retract_Count	200	200	000	Old_age	Always	-	504
193	Load_Cycle_Count	192	192	000	Old_age	Always	-	26448
194	Temperature_Celsius	105	095	000	Old_age	Always	-	45
196	Reallocated_Event_Count	197	197	000	Old_age	Always	-	3
197	Current_Pending_Sector	200	200	000	Old_age	Always	-	1
198	Offline_Uncorrectable	200	200	000	Old_age	Offline	-	0
199	UDMA_CRC_Error_Count	200	200	000	Old_age	Always	-	37
200	Multi_Zone_Error_Rate	200	200	000	Old_age	Offline	-	7

Mijzelf

In itself a Reallocated_Sector_Ct of 5 isn't alarming. It is only a problem when it's growing fast. But it can cause a degraded array, and so can the Current_Pending_Sector of 1. The latter is mildly surprising. I'd expect that to be zero after a rebuild. (A Current_Pending_Sector is a sector which is physically fine, but has a wrong checksum, so the content is basically unknown. A read will cause an I/O error (which can cause a drop from the array), but after a write it's OK.)

Should I change disk3?

When you have a decent backup I wouldn't worry about this disk, given the information you provided. (And you should have a backup. The box will fail, some day. And no, raid is not a backup.)

Can I change it with 1TB disk?

Not with raid5. With some manual work it is possible to shrink the array in a way that a 1TB member can be used, but then the remaining space is 50%.

nat_ntsb

Hi

Thanks for answering.

I'm thinking about the backup as you mentioned. I decided to use raid5 because thought it is backup but the maintenance fee is quite high. As I'm using only 60% of raid5 volume, I think 3TBx2 with raid 1 will be more suitable for my case.

But I still have 3 usable 2TB disks. Can I use 3TB disk to join this raid5 first? will it be working? Does it require any specific configuration? Later if 2TB disk fails, I will add more 3TB and change to raid 1.

Mijzelf

Yes, you can without problems use a disk which is bigger than the disk to be replaced.