Large File Ingest and Retrieval

Java command-line options and System properties can be used

• -Xmx2048m – maximum memory Java can use
• -Dfcrepo.home=/path/to/data – set the directory for permanent data
• -Djava.io.tmpdir=/path/to/tmpdir – set the directory for temp files.  Data uploaded to a federated filesystem via the REST API is written to a temp file in this directory before being moved to the federated filesystem, so this directory should have enough free space for the largest files you will upload.

Ingesting Large Files via the REST API

Based on the tests below, we believe arbitrarily-large files can be ingested and downloaded via the REST API (tested up to 1TB).  The only apparent limitations are disk space available to store the files, and a sufficiently large Java heap size.

Note: To enable fast access to large files, it is necessary to set "contentBasedSha1" : "false".  Otherwise the repository will run a SHA1 on the content for identification that could take on the order or hours when reaching into the range of > 50Gb.  For  more on this benchmarking see: https://wiki.duraspace.org/display/FF/Design+-+Large+Files.

REST API Upload/Download Roundtrip

• Platform: Linux 3.12.1-1-ARCH #1 SMP PREEMPT x86_64 GNU/Linux 16GB RAM
• Repository Profile: Single-File
• Workflow Profile: Upload/Download Roundtrip

REST API Upload/Download Roundtrip

• Platform: lib-devsandbox1.ucsd.edu (all data on NAS to handle large files)
• Repository Profile: Minimal
• Workflow Profile: Upload/Download Roundtrip

Serving Large Files via Filesystem Federation

Based on the tests below, we believe arbitrarily-large files can be projected into the repository via filesystem federation and downloaded via the REST API (tested up to 1TB).  The only apparent limitations are disk space available to store the files, and a sufficiently large Java heap size.

Filesystem Federation Download Tests

• Platform: Linux 3.12.1-1-ARCH #1 SMP PREEMPT x86_64 GNU/Linux  16GB RAM

• Repository Profile: Single-File with an additional external Resource:

  "externalSources" : {
"home-directory" : {
    "classname" : "org.modeshape.connector.filesystem.FileSystemConnector",
    "directoryPath" : "/tmp/projection",
    "projections" : [ "default:/projection => /" ],
    "readOnly" : true,
    "addMimeTypeMixin" : true
    }
}
  
  

Filesystem Federation Download Tests

• Platform: lib-devsandbox1.ucsd.edu (all data on NAS to handle large files)
• Repository Profile: Minimal, with filesystem federation:

"externalSources" : {
    "filesystem" : {
        "classname" : "org.modeshape.connector.filesystem.FileSystemConnect
        "directoryPath" : "/mnt/isilon/fedora-dev/federated",
        "projections" : [ "default:/projection => /" ],
        "readOnly" : true,
        "addMimeTypeMixin" : true,
        "contentBasedSha1" : "false"
    }
}

Direct Comparison of Different Transfer Methods

Based on the tests below, we believe arbitrarily-large files can be uploaded and downloaded via the REST API, using either repository storage or a federated filesystem (tested up to 1TB).  The only apparent limitations are disk space available to store the files, temp directory capacity, and a sufficiently large Java heap size.

• Platform: lib-devsandbox1.ucsd.edu (all data on NAS to handle large files)
• Repository Profile: Federation
• Workflow Profile: Repository/Federation/NFS/SCP Comparison

Comparison of Upload and Download Times for Different Transfer Methods

Copying Files Between Federated Filesystem and Repository Storage

Range Retrieval

Retrieving a byte range is supported and has been tested with 1TB files for both repository storage and federated filesystem.  There is an integration test in the standard test suite for verifying that range retrieval works.  By default, this test uses a small datastream size to avoid slowing down the test suite, but the size is configurable so it is easy for a developer to test files as large as local disk space allows.