Disk load balancing

• Distribute the load evenly across groups
• Distribute VDisks evenly across block store volumes
• Changing the number of slots for VDisks on PDisks

YDB supports two methods for the disk load distribution:

Distribute the load evenly across groups

At the bottom of the Hive web-viewer page there is a button named “Reassign Groups”.

Distribute VDisks evenly across block store volumes

If VDisks aren’t evenly distributed across block store volumes, you can move them one at a time from overloaded store volumes.

Changing the number of slots for VDisks on PDisks

To add storage groups, redefine the host config by increasing the number of slots on PDisks.

Before that, you need to get the config to be changed. You can do this with the following command:

Command {
  TReadHostConfig{
    HostConfigId: <host-config-id>
  }
}

kikimr -s <endpoint> admin bs config invoke --proto-file ReadHostConfig.txt

Insert the obtained config into the protobuf below and edit the PDiskConfig/ExpectedSlotCount field value in it.

Command {
  TDefineHostConfig {
    <host config>
  }
}

kikimr -s <endpoint> admin bs config invoke --proto-file DefineHostConfig.txt