Nearline Storage

Overview

This page briefly describes how one can move objects / studies from local cache archives to long term nearline storage. A nearline storage may be required to back up the studies, eventually freeing up space from local archives acting as cache.

Basic Configuration

• Upto archive version 5.23.3, exporting objects of studies from local cache archives to long term nearline storage made use of Wildfly's Java Messaging Service. Requires corresponding queue to be added in Wildfly configuration (if not already present)

  [standalone@localhost:9993 /] jms-queue add --queue-address=Export5 --entries=java:/jms/queue/Export5
  

• Archive version 5.24.0 onwards, Wildfly's Java Messaging service has been replaced by archive's own task scheduling mechanism, hence adding above JMS queue configuration in Wildfly is not required.

Using Archive UI

• Go to Configuration page, Devices tab and edit dcm4chee-arc device. Edit extension of Device Extension, next Edit extension of Archive Device. Create a new Child Object for
  • Storage Descriptor
  • Exporter Descriptor
  • Export Rule
  • Queue

Note :

• Queue configuration differs based on installed archive version.
• Export Rule may be configured if objects of studies shall be exported to nearline storage on receive of studies trigger.

Using LDAP

One may

• create a LDIF file (e.g.):

    version: 1
    dn: dcmStorageID=nearline,dicomDeviceName=dcm4chee-arc,cn=Devices,cn=DICOM Configuration,dc=dcm4che,dc=org
    dcmInstanceAvailability: NEARLINE
    dcmProperty: pathFormat={now,date,yyyy/MM/dd}/{0020000D,hash}/{0020000E,hash}/{00080018,hash}
    dcmProperty: checkMountFile=NO_MOUNT
    objectClass: dcmStorage
    dcmStorageID: nearline
    dcmURI: ${jboss.server.data.url}/nearline/
  
    dn: dcmExporterID=CopyToNearlineStorage,dicomDeviceName=dcm4chee-arc,cn=Devices,cn=DICOM Configuration,dc=dcm4che,dc=org
    dcmExporterID: CopyToNearlineStorage
    dicomDescription: Copy to NEARLINE Storage
    dcmQueueName: Export5
    objectClass: dcmExporter
    dicomAETitle: DCM4CHEE
    dcmURI: storage:nearline
  
    dn: cn=Copy to NEARLINE Storage,dicomDeviceName=dcm4chee-arc,cn=Devices,cn=DICOM Configuration,dc=dcm4che,dc=org
    dcmExporterID: CopyToNearlineStorage
    dcmDuration: PT1M
    dcmEntity: Series
    dcmProperty: SendingApplicationEntityTitle=NEARLINE
    objectClass: dcmExportRule
    cn: Copy to NEARLINE Storage
  

Queue configuration for archive versions upto 5.23.3

    dn: dcmQueueName=Export5,dicomDeviceName=dcm4chee-arc,cn=Devices,cn=DICOM Configuration,dc=dcm4che,dc=org
    dicomDescription: Nearline Storage Export Tasks
    dcmQueueName: Export5
    dcmMaxRetries: 10
    dcmRetryDelayMultiplier: 200
    dcmRetryDelay: PT30S
    objectClass: dcmQueue
    dcmMaxRetryDelay: PT10M
    dcmPurgeQueueMessageCompletedDelay: P1D
    dcmJndiName: jms/queue/Export5

Queue configuration for archive version 5.24.0 onwards

    dn: dcmQueueName=Nearline Storage Export,dicomDeviceName=dcm4chee-arc,cn=Devices,cn=DICOM Configuration,dc=dcm4che,dc=org
    dcmPurgeQueueMessageCompletedDelay: P1D
    dcmRetryDelay: PT30S
    dcmMaxRetries: 10
    dicomDescription: Nearline Storage Export Tasks
    dcmQueueName: Nearline Storage Export
    objectClass: dcmQueue
    dcmRetryDelayMultiplier: 200
    dcmMaxRetryDelay: PT10M

and import it to the LDAP Server by using the ldapmodify command line utility.

One may refer to

• Storage Descriptor,
• Exporter Descriptor,
• Export Rule,
• Queue, to understand the description of attributes.

Refer ISO-8601 Duration format for more know-how on Durations. Go to the Control tab on Configuration page in archive UI and reload the configuration.

Tests

If export rule is configured, studies shall be exported to nearline storage on receive of studies by local archive.

• Store studies to archive using storescu tool.
• Verify export tasks creation in Monitoring page Export tab. Alternatively, choose to manually export the studies to nearline storage
• Go to Navigation page Studies tab and search for required studies using one or more specific query filters.
• Choose to export single study / series / object to nearline storage. Alternatively, export studies matching the
  specified query filters using Export Matching Studies from More Functions dropdown.
• Verify export tasks creation in Monitoring page Export tab.

Once Task Polling Interval is reached, export tasks are processed and the objects of studies shall be written out to configured nearline storage at specified scheduledTime. When exporting studies to nearline storage is succcessful, verify Storage IDs of Study on each of the studies is updated and reflects storage ID of the configured nearline storage.

Storage IDs of Study	(7777,1028)	LO	fs1,nearline