In Data Service Manager, A Postgres Error may report: "could not resize shared memory segment: No space left on device"
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In Data Service Manager, A Postgres Error may report: "could not resize shared memory segment: No space left on device"

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Article ID: 401667

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Updated On: 06-25-2025

Products

VMware Data Services Manager

Issue/Introduction

In certain cases, an operation in Postgres may fail with the error similar to:

ERROR:  could not resize shared memory segment "/PostgreSQL.3907895188" to 66430848 bytes: No space left on device

Environment

Data Services Manager

Cause

This message usually appears when parallelized operations request high amount for dynamic shared memory each.

DSM Postgres databases are preconfigured with a default dynamic shared memory size of 64Mi. While this is sufficient for small databases, it may be inadequate for larger or more complex workloads.

 

Resolution

To resolve this issue, increase the dynamic shared memory size by at least the amount indicated in the error message.

This can be configured by setting .spec.requestedSharedMemorySize property of the PostgresCluster resource. Note that this value must be specified in binary (power-of-two) units.

For example, if the error message indicates a shortfall of approximately 64Mi, increase the size accordingly by setting the .spec.requestedSharedMemorySize property to at least 128Mi.

spec:
  requestedSharedMemorySize: 128Mi

Note: This property is not available through the UI and must be configured via the API.
User may chose to use Terraform (https://github.com/xfirestyle2k/VCF-Data-Services-Terraform), an Infrastructure as Code tool that provides convenient approach to  operations such as scaling.