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DAOS Version 2.0 Release Notes

We are pleased to announce the release of DAOS version 2.0.


The DAOS version 2.0 java/hadoop DAOS connector has been updated to use Log4j version 2.16 and may not include the latest functional and security updates. DAOS 2.0.1 is targeted to be released in January 2022 and will include additional functional and/or security updates. Customers should update to the latest version as it becomes available.

General Support

In this release we have added the following changes to the DAOS support matrix:

  • Starting with DAOS Version 2.0, Commercial Level-3 Support for DAOS is available
  • Added support for 3rd gen Intel(r) Xeon(r) scalable processors and Intel Optane Persistent memory 200 series
  • CentOS Linux 8 and openSUSE Leap 15.3 support is added

For a complete list of supported hardware and software, refer to the Support Matrix.

Key features and improvements

Erasure code

With the 2.0 release, DAOS provides the option of Reed Solomon based EC for data protection, supporting EC data recovery for storage target failure, and data migration while extending the storage pool. Main sub-features of DAOS EC include:

  • Reed-Solomon based EC support for I/O.

  • Versioned data aggregation for EC protected object.

  • Data recovery for EC protected object.

Telemetry and monitoring

DAOS maintains metrics and statistics for each storage engine while the engines are running to provide insight into DAOS health and performance and troubleshooting. Integration with System RAS enables proactive notification of critical DAOS/Storage events. This data can be aggregated over all nodes in the system by external tools (such as a time-series database) to present overall bandwidth and other statistics. The information provided includes bytes read and written to the engine's storage, I/O latency, I/O operations, error events, and internal state.

Pool and container labels

To improve ease of use, DAOS 2.0 introduces labels (in addition to UUID) as an option to identify and reference pools and containers.

Improved usability and management capabilities

DAOS 2.0 has added a number of usability and management improvements, such as improving command structures for consistency and automated client resource management that allows DAOS to be resilient even if clients are not.

Increased flexibility in object layout

The object layout has been restructured to support an arbitrary number of targets and SSDs. This addresses a performance issue when running with a total number of targets that is not a power of two.

mpifileutils integration

Tools for parallel data set copy are located within mpiFileUtils. mpiFileUtils provides an MPI-based suite of tools to handle large datasets. A DAOS backend was written to support tools like dcp and dsync.

Known Issues and limitations

  • Application segfault with MOFED > 5.4- / DAOS-9376 Validation of CentOS 8.5 indicates an integration issue with MLNX_OFED_LINUX-5.5- and 5.4- The same issue can be reproduced with CentOS 8.4 and MOFED > 5.4-

  • High CPU utilization / DAOS-9325 Some users have reported high CPU utilization on DAOS servers when the system is at rest. The problem will be resolved in the next bug fix release.

  • daos fs copy does not support symlinks / DAOS-9254

  • No OPA/PSM2 support. Please refer to the "Fabric Support" section of the support matrix for details.

  • Premature ENOSPC error / DAOS-8943 Reclaiming free NVMe space is too slow and can cause early out-of-space errors to be reported to applications.

  • Misconfiguration of certificates causes server crash at start up / DAOS-8114

A complete list of known issues in v2.0 can be found [HERE] (!%3D%20done%20AND%20affectedVersion%20!%3D%20%222.1%20Community%20Release%22%20AND%20%22Bug%20Source%22%20!%3D%20%22non-product%20bug%22%20ORDER%20BY%20priority%20DESC).

Bug fixes

The DAOS 2.0 release includes fixes for numerous defects, including:

  • DAOS 2.0 has moved to Libfabric version 1.14 and Mercury 2.1, which includes a number of stability and scalability fixes.
  • No longer shipping DAOS tests that caused dependency conflicts with MOFED.
  • DAOS 2.0 fixes a number of bugs dealing with pool and container destroy that could result in unremovable pools/containers.
  • The interception library was not correctly intercepting mkstemp(). This has been resolved in the 2.0 release. DAOS-8822
  • DAOS v2.0 resolves a number of memory leak issues in prior test builds.

A complete list of bugs resolved in v2.0 can be found HERE.

Additional resources

Visit the online documentation for more information. All DAOS project source code is maintained in the repository. Please visit this link for more information on the licenses.

Refer to the Software Installation section of the DAOS Administration Guide for installation details.

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