Chapter 4. Performing Cross-Site Replication Operations
Bring sites online and offline. Transfer cache state to remote sites.
4.1. Cross-Site Operations with the CLI
The Data Grid command line interface lets you remotely connect to Data Grid servers, manage sites, and push state transfer to backup locations.
Prerequisites
- Start the Data Grid CLI.
- Connect to a running Data Grid cluster.
4.1.1. Bringing Backup Locations Offline and Online
Take backup locations offline manually and bring them back online.
Procedure
Check if backup locations are online or offline with the
site statuscommand://containers/default]> site status --cache=cacheName --site=NYC
Note--siteis an optional argument. If not set, the CLI returns all backup locations.Bring backup locations online with the
bring-onlinecommand://containers/default]> site bring-online --cache=customers --site=NYC
Take backup locations offline with the
take-offlinecommand://containers/default]> site take-offline --cache=customers --site=NYC
For more information and examples, run the help site command.
4.1.2. Pushing State to Backup Locations
Transfer cache state to remote backup locations.
Procedure
Use the
sitecommand to push state transfer, as in the following example://containers/default]> site push-site-state --cache=cacheName --site=NYC
For more information and examples, run the help site command.
Reference
4.2. Cross-Site Operations with the REST API
Data Grid servers provide a REST API that allows you to perform cross-site operations.
4.2.1. Getting Status of All Backup Locations
Retrieve the status of all backup locations with GET requests.
GET /v2/caches/{cacheName}/x-site/backups/Data Grid responds with the status of each backup location in JSON format, as in the following example:
{
"NYC": "online",
"LON": "offline"
}| Value | Description |
|---|---|
|
| All nodes in the local cluster have a cross-site view with the backup location. |
|
| No nodes in the local cluster have a cross-site view with the backup location. |
|
| Some nodes in the local cluster have a cross-site view with the backup location, other nodes in the local cluster do not have a cross-site view. The response indicates status for each node. |
4.2.2. Getting Status of Specific Backup Locations
Retrieve the status of a backup location with GET requests.
GET /v2/caches/{cacheName}/x-site/backups/{siteName}Data Grid responds with the status of each node in the site in JSON format, as in the following example:
{
"NodeA":"offline",
"NodeB":"online"
}| Value | Description |
|---|---|
|
| The node is online. |
|
| The node is offline. |
|
| Not possible to retrieve status. The remote cache could be shutting down or a network error occurred during the request. |
4.2.3. Taking Backup Locations Offline
Take backup locations offline with GET requests and the ?action=take-offline parameter.
GET /v2/caches/{cacheName}/x-site/backups/{siteName}?action=take-offline4.2.4. Bringing Backup Locations Online
Bring backup locations online with the ?action=bring-online parameter.
GET /v2/caches/{cacheName}/x-site/backups/{siteName}?action=bring-online4.2.5. Pushing State to Backup Locations
Push cache state to a backup location with the ?action=start-push-state parameter.
GET /v2/caches/{cacheName}/x-site/backups/{siteName}?action=start-push-state4.2.6. Canceling State Transfer
Cancel state transfer operations with the ?action=cancel-push-state parameter.
GET /v2/caches/{cacheName}/x-site/backups/{siteName}?action=cancel-push-state4.2.7. Getting State Transfer Status
Retrieve status of state transfer operations with the ?action=push-state-status parameter.
GET /v2/caches/{cacheName}/x-site/backups?action=push-state-statusData Grid responds with the status of state transfer for each backup location in JSON format, as in the following example:
{
"NYC":"CANCELED",
"LON":"OK"
}| Value | Description |
|---|---|
|
| State transfer to the backup location is in progress. |
|
| State transfer completed successfully. |
|
| An error occurred with state transfer. Check log files. |
|
| State transfer cancellation is in progress. |
4.2.8. Clearing State Transfer Status
Clear state transfer status for sending sites with the ?action=clear-push-state-status parameter.
GET /v2/caches/{cacheName}/x-site/local?action=clear-push-state-status4.2.9. Modifying Take Offline Conditions
Sites go offline if certain conditions are met. Modify the take offline parameters to control when backup locations automatically go offline.
Procedure
Check configured take offline parameters with
GETrequests and thetake-offline-configparameter.GET /v2/caches/{cacheName}/x-site/backups/{siteName}/take-offline-configThe Data Grid response includes
after_failuresandmin_waitfields as follows:{ "after_failures": 2, "min_wait": 1000 }Modify take offline parameters in the body of
PUTrequests.PUT /v2/caches/{cacheName}/x-site/backups/{siteName}/take-offline-config
4.2.10. Canceling State Transfer from Receiving Sites
If the connection between two backup locations breaks, you can cancel state transfer on the site that is receiving the push.
Cancel state transfer from a remote site and keep the current state of the local cache with the ?action=cancel-receive-state parameter.
GET /v2/caches/{cacheName}/x-site/backups/{siteName}?action=cancel-receive-state4.2.11. Getting Status of Backup Locations
Retrieve the status of all backup locations from Cache Managers with GET requests.
GET /rest/v2/cache-managers/{cacheManagerName}/x-site/backups/Data Grid responds with status in JSON format, as in the following example:
{
"SFO-3":{
"status":"online"
},
"NYC-2":{
"status":"mixed",
"online":[
"CACHE_1"
],
"offline":[
"CACHE_2"
]
}
}| Value | Description |
|---|---|
|
| All nodes in the local cluster have a cross-site view with the backup location. |
|
| No nodes in the local cluster have a cross-site view with the backup location. |
|
| Some nodes in the local cluster have a cross-site view with the backup location, other nodes in the local cluster do not have a cross-site view. The response indicates status for each node. |
4.2.12. Taking Backup Locations Offline
Take backup locations offline with the ?action=take-offline parameter.
GET /rest/v2/cache-managers/{cacheManagerName}/x-site/backups/{siteName}?action=take-offline4.2.13. Bringing Backup Locations Online
Bring backup locations online with the ?action=bring-online parameter.
GET /rest/v2/cache-managers/{cacheManagerName}/x-site/backups/{siteName}?action=bring-online4.2.14. Starting State Transfer
Push state of all caches to remote sites with the ?action=start-push-state parameter.
GET /rest/v2/cache-managers/{cacheManagerName}/x-site/backups/{siteName}?action=start-push-state4.2.15. Canceling State Transfer
Cancel ongoing state transfer operations with the ?action=cancel-push-state parameter.
GET /rest/v2/cache-managers/{cacheManagerName}/x-site/backups/{siteName}?action=cancel-push-state