BoostIO Process Fault/Recovery

In separated deployment mode, BoostIO has an independent cache process; in converged deployment mode, BoostIO and JuiceFS are loaded to one process. The cache process is responsible for processing cache client requests, data read/write cache, and resource management. The methods for troubleshooting the cache process are described as follows.

**Table 1** Cache process fault scenarios
Scenario	Impact	Handling Method	Remarks
Cache process fault	Copy data in the write cache is lost. Object data in the read cache is lost. The SDK fails to distribute requests.	The ZooKeeper heartbeat detects that the cache process is faulty and instructs the cluster management module to update the view and then release the new view. Partition data affected by the process fault is forcibly evicted to the back-end storage.	If the cache process is temporarily faulty, only the partition view is changed. If the cache process is permanently faulty, the cluster management module removes the node from the cluster and changes both the node view and partition view. The time window for determining temporary faults is configurable.
Cache process recovery	Read/write cache functions need to be restored.	Temporary fault: The ZooKeeper heartbeat detects that the cache process is recovered and instructs the cluster management module to update the view and then release the new view. Permanent fault: The removed node is added to the cluster as a new node for expansion.	None

Parent topic: Troubleshooting