Adaptive Write Cache features with Products VTrak E5000, VTrak D5000, and Vess R3000 Series use a caching method called C2F (Copy to Flash function) to protect our cache. The 72 hour threshold no longer applies to this application method, as with the older VTrak models.
What to look for if experiencing low performance and write cache is affecting.
In the event that the battery backup cycle is at 0 or missing the Adaptive writeback cache would swtich to Adaptive write through if any of these conditions occurs.
In the example picture below the backup cycle is almost at 0. This is where to view. If the reaches 0. The adaptive writeback will be switched to writethrough mode.
In this picture below the battery is missing. In the C2F method this will change the cache from writeback to writethrough.
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)