All data in the subsystem’s controller cache is protected assuming you have both Batteries present and fully charged with at least 72 hours of hold time. Please reference the User Manual on “adaptive write cache” function.

In the event the battery becomes marginal and adaptive write cache feature is enabled (enabled by default) the controller firmware will switch the controller write cache to write thru to protect controller cache data. Physical disk cache is not protected. If this is a concern it is possible to turn off physical disk write caching from WebPAM interface or the CLI. This is a global setting for all drives and it can be found in the WebPAM interface under Device--> PhysicalDrive--> Global Physical Drive Settings See screenshot below). Turning off drive write caching will significantly reduce write performance.   Read performance will not be affected



From CLI you can SSH into the Vess Rxxx or VTrak Dxxx:

ssh administrator@<IPAddress> 

passoword: password

For the drive global settings help type:

administrator@cli> phydrv -h (this will give you the CLI command line syntax)


How do you check to see if the Adaptive Write Cache feature is disabled? You can check from CLI also the dashboard on the web interface will indicate the problem.

WriteThroughMode: 1 means the Volume write-back is disabled. (See below)

WriteThroughMode: 0 means the Volume write-back is enabled.

administrator@cli> ctrl -v

CtrlId: 1                               Alias: 
OperationalStatus: OK, BGA Running      PowerOnTime: 69 hours 14 minutes
ControllerRole: Secondary               ReadinessStatus: Active
LUNAffinity: Enabled                    LunmappingMethod: Name Based
CacheUsagePercentage: 0                 DirtyCachePercentage: 0
PartNo: F29VR3620000009                 SerialNo: MD4L19915700025
HWRev: A2                               WWN: 2100-0001-5562-fc11
CmdProtocol: SCSI-3                     ALUA: Enabled
MemType1: DDR4 SDRAM  (Slot 1)          MemSize1:  16 GB  (Slot 1)
MemType2: DDR4 SDRAM  (Slot 2)          MemSize2:  16 GB  (Slot 2)
FlashType: Flash Memory                 FlashSize: 16 GB
NVRAMType: SRAM                         NVRAMSize: 1 MB
BootLoaderVersion: 15.27.0000.38        BootLoaderBuildDate: N/A
FirmwareVersion: 13.03.0000.07          FirmwareBuildDate: Aug 14, 2019
SoftwareVersion: 13.03.0000.07          SoftwareBuildDate: Aug 14, 2019
OverallRAIDStatus: OK                   PhyDrvPresent: 8
PhyDrvOnline: 7                         PhyDrvOffline: 0
PhyDrvPFA: 0                            GlobalSparePresent: 1
DedicatedSparePresent: 0                RevertibleGlobalSparePresent: 1
RevertibleDedicatedSparePresent: 0      RevertibleGlobalSpareUsed: 0
RevertibleDedicatedSpareUsed: 0         WriteThroughMode: 1
MaxSectorSize: 4 KB                     PreferredCacheLineSize: 64
CacheLineSize: 64                       Coercion: Enabled
CoercionMethod: GBTruncate              SMARTLog: Disabled
SMARTPollingInterval: 10 minutes        MigrationStorage: DDF
CacheFlushInterval: 3                   PollInterval: 15
AdaptiveWBCache: Enabled                HostCacheFlushing: Disabled
ForcedReadAhead: Disabled               CommonWorld: Disabled
Liquid: Disabled                        DriveCmd: Enabled
PowerSavingIdleTime: Never              PowerSavingStandbyTime: Never
PowerSavingStoppedTime: Never           PseudoDeviceType: CTRL
PerfectRebuildAvailable: 64             VAAIsupport: Enabled
SSDTrimSupport: Disabled                M.2DevicePresent1: No
M.2DeviceSize1: 0 GB(s)
 Another clear indicated is a missing battery:

administrator@cli> battery

Id: 1                                   EnclosureId: 1
Status: Charging                        Chemistry: Li-Ion
CellType: 2-Cell                        EstimatedBackupCycle: 3
TempThresholdDischarge: 70C/158F        TempThresholdCharge: 50C/122F
Temperature: 25C/77F                    CycleCount: 1
Voltage: 8177mV                         Current: 0mA
RemainingCapacity: 94%                  TotalPowerOnHours: 6 Days 17 Hours
Id: 2                                   EnclosureId: 1
Status: Not present                     Chemistry: 
CellType:                               EstimatedBackupCycle: 
TempThresholdDischarge:                 TempThresholdCharge: 
Temperature:                            CycleCount: 
Voltage:                                Current: 
RemainingCapacity:                      TotalPowerOnHours: