Azure Storage

This topic describes Azure ADLS Gen2 and Dremio configuration information.

The Azure Storage is the foundation for the ADLS Gen2 service. With Dremio's implementation as a data source, ADLS Gen2 files systems can be configured along with blob containers and filesystem whitelists.

Dremio Configuration

Settings for Dremio configuration are provided in the following tabs:

  • General
  • Advanced Options
  • Reflection Refresh
  • Metadata
  • Sharing

General

Dremio Field Azure Property Description
Resource Name Name Name of the Azure Storage source.
Connection Account Name Name of the account.
Account Kind Select either StorageV1 or StorageV2. Default: StorageV2
Encrypt connection Sets a forced encryption over TLS.
Authentication Shared Access Key Generated password value for the registered application

Azure Storage General Settings

Advanced Options

Advanced Options include:

  • Enable asynchronous access when possible (default)
  • Enable exports into the source (CTAS and DROP).
  • Root Path -- Root path for the source.
  • Advanced Properties -- A list of connection properties (name and value).
  • Blob containers and Filesystem Whitelist -- Specifies a list of containers to include. Note that this disables automated container discovery.

Azure Storage Advanced Options Settings

Reflection Refresh

Reflection refresh policy options include:

  • Never refresh -- Specifies how often to refresh based on hours, days, weeks, or never.
  • Never expire -- Specifies how often to expire based on hours, days, weeks, or never.

Azure Storage Reflections Refresh Settings

Metadata

The metadata settings include:

  • Dataset handling options
  • Metadata refresh options

Azure Storage Metadata Settings

Dataset Handling

  • Remove dataset definitions if underlying data is unavailable (Default).
    If this box is not checked and the underlying files under a folder are removed or the folder/source is not accessible, Dremio does not remove the dataset definitions. This option is useful in cases when files are temporarily deleted and put back in place with new sets of files.
  • Automatically format files into physical datasets when users issue queries. If this box is checked and a query runs against the un-promoted PDS/folder, Dremio automatically promotes using default options. If you have CSV files, especially with non-default options, it might be useful to not check this box.

Metadata Refresh

  • Dataset Discovery -- Refresh interval for top-level source object names such as names of DBs and tables.
    • Fetch every -- Specify fetch time based on minutes, hours, days, or weeks. Default: 1 hour
  • Dataset Details -- The metadata that Dremio needs for query planning such as information needed for fields, types, shards, statistics, and locality.
    • Fetch mode -- Specify either Only Queried Datasets, All Datasets, or As Needed. Default: Only Queried Datasets
      • Only Queried Datasets -- Dremio updates details for previously queried objects in a source.
        This mode increases query performance because less work is needed at query time for these datasets.
      • All Datasets -- Dremio updates details for all datasets in a source. This mode increases query performance because less work is needed at query time.
      • As Needed -- Dremio updates details for a dataset at query time. This mode minimized metadata queries on a source when not used, but might lead to longer planning times.
    • Fetch every -- Specify fetch time based on minutes, hours, days, or weeks. Default: 1 hour
    • Expire after -- Specify expiration time based on minutes, hours, days, or weeks. Default: 3 hours

Sharing

Sharing options for which users can edit include:

Azure Storage Sharing Settings

Distributed Storage

The Azure Storage is the foundation for the ADLS Gen2 service. See Distributed Storage for information about configuring for distributed storage.

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