URL

https://docs.openshift.com/container-platform/4.14/scalability_and_performance/optimization/optimizing-storage.html#recommended-configurable-storage-technology_persistent-storage

https://docs.openshift.com/container-platform/4.14/scalability_and_performance/optimization/optimizing-storage.html#specific-application-storage-recommendations

SECTION

Scalability and performance > Scalability and performance optimization > Recommended configurable storage technology

Scalability and performance > Scalability and performance optimization > Specific application storage recommendations

DESCRIPTION

Issue 1

In section Scalability and performance > Scalability and performance optimization > Recommended configurable storage technology is present the Table 2. Recommended and configurable storage technology is said for Loki:

This information is wrong because of:

 Loki needs two different kind of storage:

• permanent storage: must have object storage
• temporary storage: Block (must have and recommended) or File (Configurable but can corrupt the data and performance issues as described in 6 for Elasticsearch

Issue 2

In the section https://docs.openshift.com/container-platform/4.14/scalability_and_performance/optimization/optimizing-storage.html#specific-application-storage-recommendations is said:

Loki Operator:

The preferred storage technology is S3 compatible Object storage.

Block storage is not configurable

As indicated in Issue 1 this aseveration is wrong as:

• For permanent storage is mandatory to have available S3 compatible Object storage.
• For temporary storage is recommended to use Block storage. File storage is Configurable, but not recommended because of performance issues and could lead to corrupt the data

Issue 3

In the section Recommended configurable storage technology is observed the note 6 in the Elasticsearch Logging row where the note says:

⁶ For logging, review the recommended storage solution in Configuring persistent storage for the log store section. Using NFS storage as a persistent volume or through NAS, such as Gluster, can corrupt the data. Hence, NFS is not supported for Elasticsearch storage and LokiStack log store in OpenShift Container Platform Logging. You must use one persistent volume type per log store.

NFS should be supported for Loki, even, when not recommended.

 Issue 4

Similar to the warning for Elasticsearch in the Logging Documentation section Configuring persistent storage for the log store where it's said:

Using NFS storage as a volume or a persistent volume (or via NAS such as Gluster) is not supported for Elasticsearch storage, as Lucene relies on file system behavior that NFS does not supply. Data corruption and other problems can occur.

It should be expected a Warning for Loki indicating that for the temporary storage, the recommended is Block and NFS is not recommended as per performance.