Package com.linkedin.davinci.storage

Class DiskHealthCheckService

java.lang.Object

com.linkedin.venice.service.AbstractVeniceService

com.linkedin.davinci.storage.DiskHealthCheckService

All Implemented Interfaces:

Closeable, AutoCloseable

public class DiskHealthCheckService
extends AbstractVeniceService

DiskHealthCheckService will wake up every 10 seconds by default and run a health check in the disk by writing 64KB random data, read them back and verify the content; if there is any error within the process, an in-memory state variable "diskHealthy" will be updated to false; otherwise, "diskHealthy" will be kept as true. If there is a SSD failure, the disk operation could hang forever; in order to report such kind of disk failure, there is a timeout mechanism inside the health status polling API; a total timeout will be decided at the beginning: totalTimeout = Math.max(30 seconds, health check interval + disk operation timeout) we will keep track of the last update time for the in-memory health status variable, if the in-memory status haven't been updated for more than the totalTimeout, we believe the disk operation hang due to disk failure and start reporting unhealthy for this server.

Nested Class Summary

Nested classes/interfaces inherited from class com.linkedin.venice.service.AbstractVeniceService

AbstractVeniceService.ServiceState

Field Summary

Fields inherited from class com.linkedin.venice.service.AbstractVeniceService

logger, serviceState

Constructor Summary

Constructors

Constructor	Description
DiskHealthCheckService(boolean serviceEnabled, long healthCheckIntervalMs, long diskOperationTimeoutMs, String databasePath, long diskFailServerShutdownTimeMs)

Method Summary

Modifier and Type	Method	Description
String	getErrorMessage()
boolean	isDiskHealthy()
boolean	startInner()
void	stopInner()

Methods inherited from class com.linkedin.venice.service.AbstractVeniceService

close, getName, isRunning, start, stop

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DiskHealthCheckService

public DiskHealthCheckService(boolean serviceEnabled,
 long healthCheckIntervalMs,
 long diskOperationTimeoutMs,
 String databasePath,
 long diskFailServerShutdownTimeMs)

Method Details

startInner

public boolean startInner()

Specified by:

startInner in class AbstractVeniceService

Returns:

true if the service is completely started, false if it is still starting asynchronously (in this case, it is the implementer's responsibility to set AbstractVeniceService.serviceState to AbstractVeniceService.ServiceState.STARTED upon completion of the async work).

isDiskHealthy

public boolean isDiskHealthy()

getErrorMessage

public String getErrorMessage()

stopInner

public void stopInner()

Specified by:

stopInner in class AbstractVeniceService