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Título
PERC battery is low / Write policy on Integrated RAID Controller was changed to Write Through. -
Descrição
Errors such as 'PERC battery is low" or "Write policy on Integrated RAID Controller was changed to Write Through." will come up on the iDrac while the controller battery goes through its learning cycle. This is usually done every 90 days or can be started manually if needed. -
Causa
1. Battery Transparent Learn CycleA transparent learn cycle is a periodic operation that calculates the charge that is remaining in the battery to ensure there is sufficient energy. The operation runs automatically, and causes no impact to the system or controller performance.The controller automatically performs the Transparent Learn Cycle (TLC) on the battery to calibrate and gauge its charge capacity once every 90 days. The operation can be performed manually, if required.All PERC 8 (H310 - H710) and above have this feature.2. Battery Learn CycleThe time frame for completion of a learn cycle is a function of the battery charge capacity and the discharge/charge currents used. The expected time frame for completion of a learn cycle is approximately seven hours and consists of the following parts:Learn cycle discharge cycle: approximately three hoursLearn cycle charge cycle: approximately four hoursLearn cycles shorten as the battery capacity deteriorates over time.Note: In PERC H700 and previous, virtuals disks automatically switch to Write-Through mode when the battery charge is low because of a learn cycle. Once the battery charge is sufficient, Write-Back mode will be re-enabled.During the discharge phase of a learn cycle, the battery charger is disabled and remains disabled until the battery is discharged. After the battery is discharged, the charger is re-enabled.When the learn cycle detects the battery can no longer store enough charge for 24 hours you will receive a "Predicted failure" message in the system logs, telling you the battery is near the end of it's useful life and needs to be replaced. -
Resolução
A "Battery failed" message during the learn cycle is considered normal, and can safely be ignored. The battery should return to a normal state within a few minutes.A "Battery failed" message outside of the learn cycle would indicate the battery has reached the end of it's life and needs immediate replacement. Please open a service request and include a DSET for the engineer to review the battery status.A DSET can be gathered through the following steps:1.In the left navigation menu, click Support > Diagnostics.The Diagnostics page is displayed, and this page lists all current diagnostics log files.2.In the Action menu in the upper right corner of the page, click Generate.The Generate Diagnostics pane is displayed.3.In the Select Diagnostics Type drop-down list, select "dset" from the following options.