Disc degraded after Firmware upgrade to 6.5.2

I think it be wise to shut down the system and test disk 2 in a windows PC with lifeguard.  If you don't have a backup you should certainly make one - your data is at risk.

One way to proceed is to back everything up, do a factory reset and then rebuild the NAS, and restore the data.

There are some odd things going on in the logs. hopefully netgear will take a look.  spindown.log enables spindown on disk 2, but the disk never is spundown. This goes back to last June (as far as spindown goes back), so it is not new.

disk_info.log only shows disk 1.  smart_history shows both disks (and both have a couple of pending sectors errors).

There are a couple of other issues going on, which I don't really understand the cause.

One is this snippet (which repeats)

Sep 29 06:52:31 Rosen-NAS smbd[23255]: [2016/09/29 06:52:31.607780, 0] ../source3/smbd/oplock.c:192(update_num_read_oplocks)
Sep 29 06:52:31 Rosen-NAS smbd[23255]: PANIC: assert failed at ../source3/smbd/oplock.c(192): d->num_share_modes == 1
Sep 29 06:52:31 Rosen-NAS smbd[23255]: [2016/09/29 06:52:31.611268, 0] ../source3/lib/util.c:788(smb_panic_s3)
Sep 29 06:52:31 Rosen-NAS smbd[23255]: PANIC (pid 23255): assert failed: d->num_share_modes == 1
Sep 29 06:52:31 Rosen-NAS smbd[23255]: [2016/09/29 06:52:31.612039, 0] ../source3/lib/util.c:899(log_stack_trace)
Sep 29 06:52:31 Rosen-NAS smbd[23255]: BACKTRACE: 0 stack frames:
Sep 29 06:52:31 Rosen-NAS smbd[23255]: [2016/09/29 06:52:31.612518, 0] ../source3/lib/dumpcore.c:318(dump_core)
Sep 29 06:52:31 Rosen-NAS smbd[23255]: dumping core in /var/cores

There are also regular ethernet over-runs, which might be related to your poor performance.

Sep 29 19:22:26 Rosen-NAS kernel: [395773.553715] mvneta d0074000.ethernet eth0: bad rx status 0f830000 (overrun error), size=1024
Sep 29 19:22:29 Rosen-NAS kernel: [395775.997205] mvneta d0074000.ethernet eth0: bad rx status 0f830000 (overrun error), size=1024
Sep 29 19:22:35 Rosen-NAS kernel: [395782.477936] mvneta d0074000.ethernet eth0: bad rx status 0f830000 (overrun error), size=1024
Sep 29 19:22:35 Rosen-NAS kernel: [395782.477960] mvneta d0074000.ethernet eth0: bad rx status 0f830000 (overrun error), size=512
Sep 29 19:22:39 Rosen-NAS kernel: [395786.820422] mvneta d0074000.ethernet eth0: bad rx status 0f830000 (overrun error), size=1024