Testing DSE Tiered Storage configurations

Conduct local configuration testing of DSE Tiered Storage before deploying to the cluster.

DataStax recommends local configuration testing before deploying cluster wide, or for storage configurations that do not map cleanly to the database with CREATE or ALTER table statements. Test adjustments on one or two nodes before deploying cluster wide. You can add local configuration options to overwrite the tiered storage settings in the table schema. You cannot overwrite the class or the tiered storage configuration name.

dse.yaml

The location of the dse.yaml file depends on the type of installation:

Package installations	/etc/dse/dse.yaml
Tarball installations	`installation_location`/resources/dse/conf/dse.yaml

Prerequisites

Complete DSE Tiered Storage configuration steps before you adjust and test the configurations.

Procedure

To overwrite the settings in the table schema in the local file, add a local_options key to an existing tiered storage configuration.

For example, for this dse.yaml configuration:

tiered_storage_options:
    strategy1:
      tiers: 
        - paths:
          - /mnt1
        - paths:
          - /mnt2
        - paths:
          - /mnt3

And this existing table schema with

'max_tier_ages':
          '3600,7200'

CREATE TABLE ks.tbl (k INT, c INT, v INT, PRIMARY KEY (k, c)) 
WITH COMPACTION={'class':'TieredCompactionStrategy',  
'tiering_strategy': 'TimeWindowStorageStrategy', 
    'config': 'strategy1',  
    'max_tier_ages': '3600,7200'};

You can adjust the max_tier_ages value to 7200,10800 on a single node, by adding the local_options key like this:

tiered_storage_options:
    strategy1:
      local_options:
        max_tier_ages: "7200, 10800"
      tiers: 
        - paths:
          - /mnt1
        - paths:
          - /mnt2
        - paths:
          - /mnt3

Restart the node.
After the node starts, the tiered storage strategies that use strategy1 now use max_tier_ages values "7200,10800", instead of "3600,7200" as configured on the table schema.

To monitor the tiered storage behavior of individual tables, use the dsetool tieredtablestats command:

dsetool tieredtablestats

ks.tbl
  Tier 0:
    Summary:
      max_data_age: 1449178580284
      max_timestamp: 1449168678515945
      min_timestamp: 1449168678515945
      reads_120_min: 5.2188117172945374E-5
      reads_15_min: 4.415612774014863E-7
      size: 4839
    SSTables:
      /mnt2/ks/tbl-257cecf1988311e58be1ff4e6f1f6740/ma-3-big-Data.db:
        estimated_keys: 256
        level: 0
        max_data_age: 1449178580284
        max_timestamp: 1449168678515945
        min_timestamp: 1449168678515945
        reads_120_min: 5.2188117172945374E-5
        reads_15_min: 4.415612774014863E-7
        rows: 1
        size: 4839
  Tier 1:
    Summary:
      max_data_age: 1449178580284
      max_timestamp: 1449168749912092
      min_timestamp: 1449168749912092
      reads_120_min: 0.0
      reads_15_min: 0.0
      size: 4839
    SSTables:
      /mnt3/ks/tbl-257cecf1988311e58be1ff4e6f1f6740/ma-4-big-Data.db:
        estimated_keys: 256
        level: 0
        max_data_age: 1449178580284
        max_timestamp: 1449168749912092
        min_timestamp: 1449168749912092
        reads_120_min: 0.0
        reads_15_min: 0.0
        rows: 1
        size: 4839