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|  |
| [](https://incubator-crail.readthedocs.io/en/latest/?badge=latest) |
| |
| # Apache Crail (incubating) |
| |
| Apache Crail is a fast multi-tiered distributed storage system designed from ground up for high-performance network and storage hardware. |
| It marks the backbone of the Crail I/O architecture, which is described in more detail on [crail.incubator.apache.org](http://crail.incubator.apache.org). |
| The unique features of Crail include: |
| |
| * Zero-copy network access from userspace |
| * Integration of multiple storage tiers such DRAM, flash and disaggregated shared storage |
| * Ultra-low latencies for both meta data and data operations. For instance: opening, reading and closing a small file residing in the distributed DRAM tier less than 10 microseconds, which is in the same ballpark as some of the fastest RDMA-based key/value stores |
| * High-performance sequential read/write operations: For instance: read operations on large files residing in the distributed DRAM tier are typically limited only by the performance of the network |
| * Very low CPU consumption: a single core sharing both application and file system client can drive sequential read/write operations at the speed of up to 100Gbps and more |
| * Asynchronous API leveraging the asynchronous nature of RDMA-based networking hardware |
| * Extensible plugin architecture: new storage tiers tailored to specific hardware can be added easily |
| |
| Crail is implemented in Java offering a Java API which integrates directly with the Java off-heap memory. Crail is designed for performance critical temporary data within a scope of a rack or two. |
| |
| ## Documentation |
| |
| For information about how to deploy, run, test and program against Crail: |
| * Refer to https://incubator-crail.readthedocs.org |
| * Or build from source by running `make html` in `/doc` and opening `/doc/build/html/index.html` |
| |
| |
| ## Community |
| |
| Please join the Crail developer mailing list for discussions and notifications. The list is at: |
| |
| dev@crail.incubator.apache.org. |
| |
| ## Disclaimer |
| |
| Apache Crail is an effort undergoing incubation at The Apache Software Foundation (ASF), sponsored by the Apache Incubator PMC. |
| Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, |
| and decision making process have stabilized in a manner consistent with other successful ASF projects. |
| While incubation status is not necessarily a reflection of the completeness or stability of the code, |
| it does indicate that the project has yet to be fully endorsed by the ASF. |
