Hello, dear!
Have a nice day!
If a controller fails in an engine on a mid-range OceanStor V5 storage system, the system stays in the write-back state without interrupting ongoing services or affecting the performance. By default, a mid-range OceanStor V5 storage system stays in the single-controller write-back state for eight days with an alarm reported until technical support engineers replace the failed controller.
The write-back state turns to the write through state with over 50% performance deterioration if eight days expire and the failed controller is not replaced. If two controllers fail in an engine one by one, the OceanStor 6800 V5/6800F V5/18000 V5/18000F V5 stays in the write-back state for an unlimited period of time until the failed controllers are replaced, balancing both the performance and reliability.
If three controllers fail in an engine, the OceanStor 6800 V5/6800F V5/18000 V5/18000F V5 stays in the write-back state for eight days by default. After the period expires without controller replacement, an alarm will be reported and the write-back state will turn into the write through state. You can specify the write-back duration from 0 to 2160 hours using the command-line interface (CLI).
How to replace controller:
https://support.huawei.com/hedex/hdx.do?lib=EDOC1000182280YEG12274&docid=EDOC1000182280&lang=en&v=16&tocLib=EDOC1000182280YEG12274&tocV=16&id=EN-US_TOPIC_0123341476&tocURL=resources/en-us_topic_0123341476.html&p=t&fe=1&ui=3&keyword=replace%2Bcontroller
Hope can help you!
