Migrating to the AEM Cloud using Content Transfer tool and experiencing a Length Collision that is stopping the Extraction

[nickrabbat]

Hi all --

I am working on a AEMaaCS migration using the Content Transfer Tool and we are experiencing an Exception during Extraction phase that is causing it to fail. 

The exception is org.apache.jackrabbit.core.data.DataStoreException: Length Collision (see below) and the source is an AEM 6.5 SP13 instance w/ content-transfer.all-3.0.0.zip package installed.  

The extraction configuration includes a wipe "Overwrite staging container during extraction" and include versions is part of the Migration Set configuration. Pre copy and User mapping is not part of the Migration Set configuration. 

Any thoughts on how to resolve?  I am running a consistency check now -- but that is generally to identify missing binaries.  I am at a loss on this issue since it seems related to the Azure Blob Store being targeted. 

Thanks!

2023-09-10 12:28:09,672 [oak-ds-async-upload-thread-9] ERROR o.a.j.o.p.blob.UploadStagingCache - Error adding file to backend
org.apache.jackrabbit.core.data.DataStoreException: Length Collision. identifier=9dfc-c60cca9f3902f323f080762930328e64b704b2fa1b7a8c25df6f68dabc7d new length=0 old length=5770
	at org.apache.jackrabbit.oak.blob.cloud.azure.blobstorage.AzureBlobStoreBackend.write(AzureBlobStoreBackend.java:312)
	at org.apache.jackrabbit.oak.plugins.blob.AbstractSharedCachingDataStore$2.write(AbstractSharedCachingDataStore.java:173)
	at org.apache.jackrabbit.oak.plugins.blob.UploadStagingCache$3.call(UploadStagingCache.java:367)
	at org.apache.jackrabbit.oak.plugins.blob.UploadStagingCache$3.call(UploadStagingCache.java:362)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)

[kautuk_sahni]

@A_H_M_Imrul @arunpatidar  Can you please review this Question and share your thoughts? 

[Thorsten_999]

Hi Nick,

did you find a solution? I am facing the same issue [1]. I also ran a consistency check with these parameters

java -Xmx4096m -jar oak-run-1.22.17.jar datastore --check-consistency /mnt/crx/author/crx-quickstart/repository/segmentstore --fds /mnt/crx/author/oak-run-configs/FileDataStore.config --out-dir oak-run-out-dir --work-dir oak-run-temp-dir --verbose

And found many missing blobs [2]. Not sure if this is related or how to resolve these missing blobs.

With kind Regards

Thorsten

[1] 2024-03-29 08:02:00,466 [oak-ds-async-upload-thread-7] ERROR o.a.j.o.p.blob.UploadStagingCache - Error adding [...] with file [/mnt/crx/author/crx-quickstart/cloud-migration/[...]/tmp/1711697953011-0/repository/datastore/upload/82/cd/cd/82cdcd730f043df4[...]] to backend
org.apache.jackrabbit.core.data.DataStoreException: Length Collision. identifier=82cd-cd730f043df445209d514762bc49[...] new length=0 old length=13031
at org.apache.jackrabbit.oak.blob.cloud.azure.blobstorage.AzureBlobStoreBackend.write(AzureBlobStoreBackend.java:312)
at org.apache.jackrabbit.oak.plugins.blob.AbstractSharedCachingDataStore$2.write(AbstractSharedCachingDataStore.java:173)
at org.apache.jackrabbit.oak.plugins.blob.UploadStagingCache$3.call(UploadStagingCache.java:367)
at org.apache.jackrabbit.oak.plugins.blob.UploadStagingCache$3.call(UploadStagingCache.java:362)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)

[2] 28.03.2024 19:16:48.829 *WARN* [main] o.a.j.o.p.b.MarkSweepGarbageCollector - Missing Blob [7bf7ce4c38e6675e...]#310[...],/content/[...]thumb-16x9-1920x1080.jpg/jcr:content/renditions/original/jcr:content]