Old logs not visible after migrating from loki-stack to loki using existing PVC

Grafana Loki
1

We migrated from loki-stack to the loki Helm chart in AKS and reused the existing Azure Disk (PVC).

The new Loki instance mounts the same disk and writes logs successfully, but historical logs from loki-stack are not visible in Grafana (see setup and values.yaml snippet below).

The old logs should be queryable from the reused disk, but only the new logs are. We have confirmed that both the new and old logs are available on the disk in the data/loki/chunks directory.

Questions

  1. Is PVC reuse supported across loki-stack ->loki?
  2. Are config changes required to read old data?
  3. Is there a recommended migration approach?

Setup

Environment
* AKS (Azure Kubernetes Service)
* Storage: Azure Disk (PVC)
* Old: loki-stack (chart version: 2.10.2)
* New: loki (chart version: 6.53.0)

Config new (loki)

  storage:
     type: filesystem
  schemaConfig:
    configs:
      - from: "2024-01-01"
        store: boltdb-shipper
        object_store: filesystem
        schema: v11
        index:
          prefix: loki_index_
          period: "24h"
  storage_config:
    boltdb_shipper:
      active_index_directory: /data/loki/
      cache_location: /data/loki/cache
    filesystem:
     directory: /var/loki/chunks

...

singleBinary:
  enabled: true
  replicas: 1
  persistence:
    enabled: false
  extraVolumeMounts:
    - name: persistent-storage
      mountPath: /data/loki/chunks
  extraVolumes:
    - name: persistent-storage
      persistentVolumeClaim:
        claimName: storage-loki-0
2

Can anyone know answer for this ? - are are also experiencing this.

3

It doesnโ€™t look like you followed the Upgrade documentation, because I can see that

1 - Youโ€™re still using boltdb-shipper and not TSDB

2 - Youโ€™re on schema version 11, not version 13.