Aspera Sync

Aspera Sync is purpose-built by Aspera for high-performance, scalable, multidirectional asynchronous file replication and synchronization. Designed to overcome the performance and scalability shortcomings of conventional synchronization tools like rsync, Aspera Sync can scale up and out for maximum speed replication and synchronization over WANs, for today’s largest big data file stores—from millions of individual files to the largest file sizes.

Use Cases

Disaster recovery and business continuity

Robust backup and recovery policies protect business critical data and systems so enterprises can quickly recover important files, systems or an entire site in the event of a disaster. However, these policies can be undermined by slow transfer speeds between primary and backup sites, resulting in incomplete backups and extended recovery times. With FASP®-powered transfers, replication fits within the small operational window so you can meet your recovery point objective (RPO) and recovery time objective (RTO).

  • Mission critical data transfers use the entire available bandwidth between primary and backup sites, moving data quickly, efficiently and without impeding other network traffic.
  • Large data sets measuring terabytes in size can be replicated offsite securely and quickly recovered in the event of a system failure or loss of an entire site.
  • With Aspera, data can be moved on demand, or continuously synchronized in real time over the WAN, regardless of distance and network conditions, allowing a high degree of flexibility in backup scheduling and control.

Content distribution and collection

Create multi-site, multi-directional synchronization topographies to collect or distribute content, software updates and business data across remote, geographically dispersed locations, regardless of file sizes, locations and distance.

  • Multiple users and locations can access replicated data and share their updates, regardless of file sizes, location or distance.
  • Daily collection or distribution of data across a large chain of retail stores.
  • Automatic push of standardized educational content to remote schools.
  • Continuous updates of software builds to remote, geographically dispersed teams.
  • Rich media delivery from the point of ingest to remote servers for improved data and service availability.

File archiving and storage

Enterprises can improve the efficiency and utilization of their storage systems by moving inactive data from their expensive high-performance primary storage to secondary remote storage. However, moving large volumes of data using conventional tools like rsync can stress the network and impede the flow of business-critical traffic. With Aspera Sync, you can create continuous or scheduled archive jobs that move inactive data over the WAN across storage tiers fully utilizing the available bandwidth, while being fair to other network traffic.

  • Replicate entire file system, or portions of the file system, at high speed, over the WAN.
  • Preserve file attributes such as permissions, access times, ownership, etc.

Server and VM migration, replication, backup and recovery

Scaling IT infrastructure often requires rapid deployment of new servers or storage systems, while migrating the existing data and software. Moving these components onto new servers en masse is a time- and bandwidth-consuming task which can be further impeded by inefficient utilization of WAN bandwidth to transfer the data from source to destination(s). With Aspera Sync, these tasks can be automated and the data transferred at high speeds, fully utilizing the available bandwidth and without impacting other network traffic.

  • Minimize setup time, duplication and re-installation of new and existing systems by fast replication of servers and virtual machines.
  • Maintain multiple copies of complete file systems for development, sandbox, quality assurance, or standby servers.
  • Automate the replication of actual and virtual servers over wide area networks.
  • Migrate entire file systems from aging storage to newly provisioned systems in a fraction of the time.

Product Highlights

The fasp™ advantage

  • Reconciles file system changes with remote peers at extremely high speed (500 files per second+) on commodity hardware.
  • No performance degradation with increased numbers of files, or with variations in WAN conditions.
  • Transfers data between peers at full bandwidth capacity, regardless of distance and network conditions, at speeds of up to 1000X faster than rsync, over long distance and high bandwidth WANs.

High-performance, intelligent replacement for rsync

  • Unlike conventional tools, Aspera Sync intelligently recognizes changes and file operations such as moves and renames, instantaneously propagating these changes to remote peers, avoiding unnecessary data copying over the WAN.
  • Familiar rsync-like command line interface eliminates a steep learning curve and makes adoption easier and faster - the ideal replacement for rsync.

Supports complex synchronization deployments

  • Unlike unidirectional-only tools, Aspera Sync supports bidirectional and multidirectional synchronization topologies where content is changing on multiple nodes.
  • Replication jobs can be configured to run continuously for real-time synchronization, or one-time, on demand.
  • Aspera Sync ensures 100% data integrity: users can safely move, rename, and delete files or entire directory structures, without fear of data loss.

Centralized reporting and management

  • Global visibility into Sync sessions and activity across the entire network providing real-time reports on synchronization progress, per file status and throughput with Aspera Console.
  • Sync sessions can be paused and resumed, and bandwidth priority and speed can be modified on the fly.

Advanced file handling

  • Rich include and exclude filters
  • Full support for soft and hard links
  • Options for the preservation of access time, user and group IDs

File-level de-duplication

  • Duplicate files on the source system are identified and Aspera Sync instructs the target system to create a hard link rather than resending the file eliminating unnecessary transfers, reducing sync times and reducing storage use.

Universal support for virtual iNode 

  • Support for virtual iNodes in file systems that do not have constant iNodes, improving file system change detection.

Broad Platform support

  • Supports the latest versions of Windows, Linux, and Mac OS X.

First Run

Performance comparison synchronizing many small files (average size 100 KB) over WAN of 100 ms/1% Performance comparison synchronizing many large files (average size 100 MB) over WAN of 100 ms/1%

Second Run  

Synchronization time after adding 31,056 files to 1 million small files (100 KB each) over WAN of 100ms/1%   Synchronization time after adding new files to to set of large files (100 MB) over WAN of 100ms/1%

Unrivaled Aspera performance

  • Built on Aspera FASP® technology for maximum transfer speed regardless of file size, transfer distance and network conditions.
  • Precise bandwidth control ensures the entire allocated bandwidth is utilized to achieve maximum transfer speeds, while being fair to other business-critical network traffic.
  • 100% reliable data delivery with real-time reporting of transfer progress and performance.

Familiar rsync interface

  • Compatible rsync command line interface shrinks learning curve.
  • Simplifies deployment, does not require a rip and replace.

Flexible options for replication and sync of remote files and directories

  • One-to-one and one-to-many synchronization.
  • Supports both uni-directional and bi-directional synchronization in both push and pull mode between peers over WAN/LAN.
  • One-time replication as well as continuous synchronization.
  • Rich include and exclude filters

Extreme Scalability

  • Highly scalable synchronization architecture supports synchronization of millions of files and multi-terabyte file sets.
  • Concurrent synchronization session architecture with support for clustering and multi-gigabit transfer speed.

Efficient change detection and updates

  • Locally detects changes and compares them to file system snapshot without having to check with remote systems.
  • Super-fast scan to detect changes in scan-mode for large incremental data sets.
  • Quick restart after system down.
  • Replicates file moves and file renames on the source as a file move or rename on the target, avoiding unnecessary data copying.
  • Robust - waits for the system(s) to become stable (i.e., detects whether or not files are still being modified) before performing synchronization.
  • Distributed event collection system enables the fastest possible capture of file system changes on clusters of ingest servers and high availability deployments.


  • Built-in de-duplication detects multiple copies of a file at the source and stores them as links to a single copy of the file at the destination, saving transfer time, bandwidth and storage capacity.

Complete Security

  • AES SSH authentication.
  • AES-128 data encryption in transit and at rest, FIPS 140-2 compliant.
  • Data integrity verification for each transmitted block.

>> Learn more about Aspera's FASP security model


  • Global visibility into Sync sessions and activity across the entire network
  • Real-time reports on synchronization progress, per file status and throughput with Aspera Console.
  • Sync sessions can be paused and resumed, and bandwidth priority and speed can be modified on the fly
  • User account and workgroup administration, managed via either Aspera Enterprise Server or Aspera Point-to-Point when deployed as an add-on.

Universal support for virtual iNode 

  • Support for virtual iNodes in file systems that do not have constant iNodes, improving file system change detection.

Operating Systems

  • Windows: Windows 7, 8, 10 or Windows Server 2008 R2, 2012 R2, 2016
  • Linux 64-bit: RedHat 6-7, CentOS 6-7, Fedora 16-20, Ubuntu 12-15, Debian 6-7, SLES 11-12 Kernel 2.4 or higher and Glibc version 2.5+
  • Linux on z Systems s390, 64-bit: Red Hat Enterprise Linux Server (RHEL) 6-7.3, SUSE Linux Enterprise Server (SLES) 11-12
  • Mac OS X: 10.8, 10.9, 10.10, 10.11, macOS 10.12 (Sierra)
  • AIX: 6.1, 7.1
  • Solaris x86: 10
  • Solaris SPARC: 9, 10

Minimum Hardware Requirements

Refer to the minimum hardware requirements for your operating system.

Licensing and deployment

  • Licensed stand-alone or as an add-on to Aspera High-Speed Transfer Server or Aspera Endpoint.
  • One license per installed host, with tiers based on file system size (number of files).
  • If Aspera Sync is added on to an Aspera High-Speed Transfer Server (or Endpoint), then the bandwidth capacity for Aspera Sync matches the bandwidth capacity of the existing server license.


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WHAT'S NEW IN Aspera Sync 3.8

  • Sync can now use multiple scanning threads on the local and remote computers to improve performance by decreasing the time required for directory scanning after the initial scan.
  • Sync can now use a cluster as an endpoint.
  • Sync logging location, level, and size can be configured in aspera.conf using new logging settings.
  • Sync sessions with object storage can now include custom metadata if the object storage supports it (currently S3, Google, Azure, and Swift).
  • Previous Releases

    WHAT'S NEW IN Aspera Sync 3.7

    • Support for bi-directional sync between local and remote S3-compatible object storage
    • Works with the Aspera Files SaaS via new support for access keys and storage roots
    • The new recursive mtime option enables the exclusion of directories and files older than a configured timestamp
    • New delete-delay option allows the delete operations in a unidirectional sync to be delayed until the end of the synchronization
    • Improved in-memory snapshot option (avoiding delays of slow storage systems), including new asyncadmin option for file status reporting and  improved termination and shutdown robustness
    • Improved bidirectional synchronization avoiding conflicts when directory modification times change (Windows) and new --cooloff-max option for cases where files change continuously
    • Improved startup times for huge numbers of include and exclude filters
    • New support for overwrite-older option among various overwrite policies
    • Improved Reporting - A new asyncadmin option prints file attributes (mtime, recursive mtime for directories, and checksum), and onsole reports correctly when both nodes are managed.
    • New support for hardlink synchronization based on inodes
    • Support for AIX in addition to Linux, Windows, OS X, and Solaris
    • Preserve Windows ACL changes even while file content does not change & Watchd support to detect ACL and Unix permission changes (available in 3.7.4)
    • Access key authentication is now supported by using "Basic: token_string" as an argument for the -W option (available in 3.7.4)
    • Support --dedup option being used in async commands even if it is not specified in the first run; however, --dedup is rejected if the first run does not use -k (available in 3.7.4)
    • Enhanced handling of changing files by continuous Sync sessions when checksum is set to none; files that return a sharing violation error are now retried per --sharing-retry-max (available in 3.7.4)


    What's New in ASPERA SYNC 3.6

    • Version 3.6 integrates asperawatchd, a new ultra fast file system notification service designed for speed, scale and distributed change watching.
      • Quicky discovers changes in huge file systems - up to 100 million items across thousands of directories
      • The distributed architecture captures changes on any local or shared storage client host (CIFS, NFS, etc.) and aggregates all changes in real time in a single snapshot
      • Highly scalable for large numbers of concurrent clients (e.g. Aspera Drive or async clients) by allowing each client to compute its differential changes relative to a single snapshot on the server side
      • Supports push, pull and bidirectional synchronization
    • Synchronizes file attribute changes even when content is not updated, e.g. Windows ACL and Unix ownership (user and group)
    • Includes LZ compression for high performance on low capacity networks
    • A single FASP transfer session supports multiple parallel transfer channels segmented by data size, allowing small files to be synchronized (and deduplicated) in parallel with long running transfers of large files resulting in greater scalability and performance
    • Direct-to-Cloud synchronization to object storage (AWS S3, Swift) is now compatible for push, pull and bidirectional synchronization of changes on cloud storage. Now supports synchronization initiated on cloud storage in addition to cloud storage on the server side.
    • New compatibility with Windows file locking avoids errors and conflicts in bidirectional synchronization of files open in Word or other MS Office applications through graceful transparent retries and skipping of temporary/shadow backup files
    • New API for creation of sync jobs and reporting of changes.
    • New optional periodic scan capability in bidirectional continuous mode, with options to configure scan interval separately on source and destination
    • Enhanced performance for high concurrency sync (many Drive clients) with lower CPU utilization
    • New enhanced server side reporting reports Drive sync sessions and Drive users to Console and includes sync target paths