I had been noticing slow performance for several weeks, and high cpu usage. I checked the data and cache drive in maintenance mode and the appear to be ok. There does not seem to be an option to check the parity drive. The log is full of errors on Disk 0. I am assuming that disk 0 is the parity drive.  I am posting the log below.

 

[/Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514136
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514144
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514152
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514160
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514168
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514176
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514184
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514192
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514200
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514208
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514216
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514224
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514232
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514240
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514248
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514256
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514264
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514272
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514280
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514288
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514296
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514304
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514312
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514320
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514328
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514336
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514344
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514352
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514360
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514368
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514376
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514384
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514392
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514400
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514408
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514416
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514424
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514432
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514440
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514448
Dec 22 16:06:27 Tower kernel: md: disk0 read error, sector=25514456
Dec 22 16:07:54 Tower emhttp: cmd: /usr/local/emhttp/plugins/dynamix/scripts/tail_log syslogcode]

You should post your diagnostics (Tools - Diagnostics)

You should post your diagnostics (Tools - Diagnostics)

 

I have attached the Diagnostics file below.

tower-diagnostics-20151222-1628_1.zip

Doesn't look like your parity drive is having a good time as of late:

 

  5 Reallocated_Sector_Ct   0x0033   190   190   140    Pre-fail  Always       -       303
196 Reallocated_Event_Count 0x0032   001   001   000    Old_age   Always       -       217
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   Always       -       274

 

With 303 sectors already reallocated, and the drive waiting to reallocate a further 274, its time to get rid of it

 

I pulled and replaced the drive, thanks.