Confusion about write-cache setting and write-cache status on Adaptec Raid-Controller

Question

Because of performance issues I wanted to verify that Write-Caching is indeed enabled for the Adaptec ASR71605 Raid-Controller. I can see a mismatch between write-cache setting=enabledand write-cache status=off and I wonder if the cache is actually enabled or not.

When explicitly enabling the cache with arcconf setcache 1 LOGICALDRIVE 1 wb the status does not change.

Please see the arcconf output below:

root@stor ~ $ arcconf getconfig 1 ld
Controllers found: 1
----------------------------------------------------------------------
Logical device information
----------------------------------------------------------------------
Logical device number 0
   Logical device name                      : SYSTEM
   RAID level                               : 6 Reed-Solomon
   Status of logical device                 : Optimal
   Size                                     : 51188 MB
   Stripe-unit size                         : 256 KB
   Read-cache setting                       : Enabled
   Read-cache status                        : On
   Write-cache setting                      : Enabled
   Write-cache status                       : Off
   Partitioned                              : Yes
   Protected by Hot-Spare                   : No
   Bootable                                 : Yes
   Failed stripes                           : No
   Power settings                           : Disabled
   --------------------------------------------------------
   Logical device segment information
   --------------------------------------------------------
   Segment 0                                : Present (Controller:1,Enclosure:0,Slot:4)      WD-WXH...
   Segment 1                                : Present (Controller:1,Enclosure:0,Slot:5)      WD-WX1...
   Segment 2                                : Present (Controller:1,Enclosure:0,Slot:6)      WD-WXH...
   Segment 3                                : Present (Controller:1,Enclosure:0,Slot:7)      WD-WXH...
   Segment 4                                : Present (Controller:1,Enclosure:0,Slot:12)      WD-WX...
   Segment 5                                : Present (Controller:1,Enclosure:0,Slot:13)      WD-WX...
   Segment 6                                : Present (Controller:1,Enclosure:0,Slot:14)      WD-WX...
   Segment 7                                : Present (Controller:1,Enclosure:0,Slot:15)      WD-WX...

Logical device number 1
   Logical device name                      : RAPTOR
   RAID level                               : 6 Reed-Solomon
   Status of logical device                 : Optimal
   Size                                     : 5668850 MB
   Stripe-unit size                         : 256 KB
   Read-cache setting                       : Enabled
   Read-cache status                        : On
   Write-cache setting                      : Enabled
   Write-cache status                       : Off
   Partitioned                              : No
   Protected by Hot-Spare                   : No
   Bootable                                 : No
   Failed stripes                           : No
   Power settings                           : Disabled
   --------------------------------------------------------
   Logical device segment information
   --------------------------------------------------------
   Segment 0                                : Present (Controller:1,Enclosure:0,Slot:4)      WD-WXH...
   Segment 1                                : Present (Controller:1,Enclosure:0,Slot:5)      WD-WX1...
   Segment 2                                : Present (Controller:1,Enclosure:0,Slot:6)      WD-WXH...
   Segment 3                                : Present (Controller:1,Enclosure:0,Slot:7)      WD-WXH...
   Segment 4                                : Present (Controller:1,Enclosure:0,Slot:12)      WD-WX...
   Segment 5                                : Present (Controller:1,Enclosure:0,Slot:13)      WD-WX...
   Segment 6                                : Present (Controller:1,Enclosure:0,Slot:14)      WD-WX...
   Segment 7                                : Present (Controller:1,Enclosure:0,Slot:15)      WD-WX...

Write cache requires a backup battery, does your raid controller have one? — Dan, Jul 05 '15 at 06:06
Yes, the controller has an AFM-700 BBU. Write-Cache can be enforced regardless of an BBU, though. — Leon Kramer, Jul 05 '15 at 07:41
Enforced, yes. Usually enable and enforce are two different settings. Enable only works if battery is considered in good condition and has enough charge. I would start by checking your bbu status. — Dan, Jul 05 '15 at 20:02
Any chance the reboot the machine? Or better, poweroff and poweron? — Dan, Jul 06 '15 at 08:57

score 0 · Accepted Answer · answered Jul 06 '15 at 12:25

According to Adaptec support the write-cache is not working in the time between a firmware update and the next reboot.

Indeed, there has been made a firmware update without a following reboot, which can be seen with arcconf getversion if the command lists a Staged Version number.

Confusion about write-cache setting and write-cache status on Adaptec Raid-Controller

1 Answers1