Backend: abt-io

The abt-io backend uses ABT-IO (Argobots-aware I/O) for asynchronous file I/O, providing persistent storage with non-blocking operations.

When to use

Use the abt-io backend when:

You need persistent storage on traditional filesystems
You want async I/O without blocking Argobots threads
You’re storing very large blobs (multi-GB)
You don’t have persistent memory hardware
You want compatibility with standard filesystems (ext4, xfs, etc.)

Characteristics

Persistent: Data stored on disk survives restarts

Async: I/O operations execute in Argobots ULTs potentially in a separate ES

Large capacity: Limited by filesystem size

Configuration

In Bedrock configuration:

{
    "providers": [{
        "type": "warabi",
        "provider_id": 42,
        "config": {
            "target": {
                "type": "abtio",
                "config": {
                    "path": "/tmp/warabi",
                    "create_if_missing": true,
                    "override_if_exists": true,
                    "alignment": 4096,
                    "directio": false,
                    "abt_io": {

                    }
                }
            }
        }
    }]
}

Configuration options:

path: Files where regions will be stored
create_if_missing (default “false”): Whether to create the file if it is missing
override_if_exists (default “false”): Whether to override the file if it exists
directio (default “false”): Whether to open the file with O_DIRECT
alignment (default 8): alignment of regions in the file
abt_io: configuration of an ABT-IO instance (see ABT-IO section for more information)

In C++ code:

#include <warabi/Provider.hpp>

auto config = R"(
{
    "target": {
        "type": "abtio",
        "config": {
            "path": "/tmp/warabi",
            "create_if_missing": true,
            "override_if_exists": true,
            "alignment": 4096,
            "directio": false,
            "abt_io": {}
        }
    }
}
)";

warabi::Provider provider(engine, 42, config);