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FlexiCapture can process from several hundred to millions of pages per day, and support up to several thousand operators. Estimate the System load in advance, then select the architecture and the server hardware to match it. The System scales up by:
  • Adding scanning clients, verification clients, and Processing Stations
  • Adding power to the machines that host the Application, Processing, Licensing, and Database servers and the FileStorage
  • Spreading those server roles across several machines
Use these figures to pick a preliminary configuration for the FlexiCapture server components. System monitoring and bottleneck detection shows you whether the current hardware still meets your target performance, and when it is time to scale up.

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Demo

Demo is a typical configuration for demonstrations or pilot projects, and is not recommended for production-scale projects. All the System components are installed on a virtual machine or deployed on a PC. You can use MS SQL Express as the database server and install it on the same machine as the FlexiCapture servers. Instead of a separate FileStorage, you can store files directly in the database. Operators and Processing Stations can also share that machine.
In commercial projects, never install the Processing Station on a computer that hosts FlexiCapture servers or the Database Server. The Station consumes all available resources and server performance drops.

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Medium

Medium is a typical configuration for commercial projects. Each server component is installed on a dedicated machine, so you can scale each one independently.

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Deployment guidelines

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Separate the Application Server

Install the Application Server on a dedicated machine. It scales differently from the Database, Processing, and Licensing servers.
You can install the Application Server, Processing Server, and Licensing Server on one computer. That gives you server redundancy but not Application Server scalability.

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Choose a clustering technology

The Application Server and the Processing and Licensing Servers use different clustering technologies:
  • The Application Server is a web service in IIS; its scaling and reliability are achieved by clustering that uses Microsoft Network Load Balancing technology. All cluster nodes are peers running in active-active mode and can be switched off at any time.
  • The Processing Server and Licensing Server are Windows services; their reliability is achieved by creating an active-passive cluster based on Microsoft Failover Cluster technology.
Microsoft prohibits using these two technologies together on the same computer. If you need reliability but not scalability, cluster the Application Server within IIS, which also supports Microsoft Failover Cluster. The Licensing Server and Processing Server can share one machine.

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Place the Database Server

Install the Database Server on a dedicated machine, because it consumes a large share of the host’s resources. If you do combine it with other FlexiCapture servers, restrict its CPU and RAM use. Put the database files on a physically separate HDD as well, so it does not degrade the neighboring server.

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Choose FileStorage hardware

For small loads, you can use fast HDDs on the Application Server machine as the FileStorage. Use 15,000 RPM or faster SATA2 disks, in at least RAID1 for redundancy or RAID10 for better performance. Local HDDs become a bottleneck as page volume grows, especially for grayscale or color images. You also cannot scale them on the fly, because adding disks means taking the System down. For anything larger, use external storage such as NAS or SAN. The Application Server needs read-write access to it at 1 Gb/s over LAN, SCSI, Fibre Channel, or a similar interface. External storage scales smoothly.

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Network layout

The following diagram shows a typical FlexiCapture network configuration in an enterprise environment.
Diagram of a typical Medium FlexiCapture network configuration in an enterprise, where ABBYY FlexiCapture Clients pass through a firewall and 1 Gb/s switch to the ABBYY FlexiCapture Servers, with the Application Server connected directly to File Storage at 1 Gb/s and to the Database, plus the Processing and Licensing Servers, the Customer's ERP backend system, and the Processing Stations.
Connect the Application Server directly to the FileStorage and Database Server for fast and reliable communication.

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Application Server

  • CPU: 8 physical cores, 2.4 GHz or faster
  • 16 GB RAM
  • HDD: 100 GB
  • 2 NICs, 1 Gb/s: one to connect to the LAN and one to connect to the Database Server
  • FileStorage: if a SAN is used, connect it using SCSI, Fibre Channel, or InfiniBand
  • OS: Windows 2012 or later
The Application Server is the hub of all FlexiCapture communications. It handles two kinds of traffic:
  • Large binary body transfers
  • Small SOAP/JSON service requests that need a fast response
The Application Server depends on four critical resources:
  • A fast network interface for connecting to clients
  • A fast, stable connection to the FileStorage and Database Server
  • A fast multi-core CPU:
    • The higher the speed, the faster each request is handled
    • The more physical cores there are, the more requests are handled at the same time
  • Sufficient RAM, at least 2 GB per physical core
To make the most of the CPU, give the FlexiCapture Web Services application pool twice as many IIS Worker Processes as physical cores. For example, 16 IIS Worker Processes for an 8-core processor. If any of these resources causes a bottleneck, scale up the Application Server:
  • With Microsoft Network Load Balancing, which clusters several computers in the Application Server role. For more information, see Failover configuration.
  • At the hardware level, by connecting different ranges of clients to different machines in the Application Server role. For example, one machine can serve all automatic processing while another is exposed to external clients.
In any case, all machines with the Application Server role should be equally connected to the same Database and FileStorage.

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Processing Server and Licensing Server

  • 4-core CPU, 2.4 GHz or faster
  • 8 GB RAM
  • HDD: 100 GB
  • NIC: 1 Gb/s for connecting to the LAN
  • OS: Windows 2012 or later
A stable network connection is essential for these servers. Without one, document processing stops. To ensure redundancy, use Microsoft Failover Cluster. For more information, see Failover configuration. The Licensing Server holds a copy of every concurrent client’s license in memory. Its RAM requirement therefore grows with the number of scanning and verification operators working at once. Testing shows that 2 GB of RAM handles licenses for up to 1000 clients. Use the 64-bit Licensing Server for projects with many concurrent clients. To serve more clients than one server can hold, add a second Licensing Server.

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Database Server

Supported versions:
  • MS SQL Server 2014 or higher, Standard or Enterprise Edition
  • Oracle 12c Enterprise Edition
ABBYY FlexiCapture supports MS SQL Server and Oracle installed on any platform. Both vendors publish their own guidance on optimal settings, scaling, and fault tolerance.

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Database Server hardware

For MS SQL Server:
  • CPU: 8 physical cores, 3.4 GHz or faster
  • 16 GB RAM or more
  • HDD: 400 GB
  • OS: Windows 2012 or later
For Oracle, use an Oracle Exadata Database Machine X2-2, Quarter Rack.

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MS SQL Server settings

  • Add as much RAM as possible to the Database Server machine, so that most of the database files sit in RAM and are read faster
  • Use a fast HDD, preferably an SSD, for the part of the database that stays on disk
  • Avoid database modes with transaction delays, such as mirroring
  • Set the database recovery model to Simple
  • Store the database and its log on separate disks
  • Update indexes regularly for frequently changing tables (Document, Page, Batch, Task, and EventLog). Otherwise an index may grow larger than the data in its table

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FileStorage

  • NAS or SAN, connected via LAN, SCSI, Fibre Channel, or InfiniBand
  • Read-write speed: from 100 MB/s, depending on your workload
  • Capacity: from 5 TB, depending on your workload
Size both figures for your own project. For more information, see FileStorage sizing. Search indexing and anti-virus scanning of FileStorage contents may decrease performance or block access to files that are being processed in the System.
Use a fault-tolerant storage technology, for example RAID 10.

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FileStorage sizing

Two factors drive the read-write speed and the capacity you need. Size for both.

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Page throughput and color mode

Read-write speed depends on the average and peak pages processed per hour and per 24 hours, and on their color mode. Estimate the input flow in bytes per second from the typical file sizes for pages scanned in color, grayscale, and black-and-white. For more information, see Performance metrics. Images make up the majority of data transferred within the System. Analyze the processing workflow and define two values:
  • R, the number of stages where page images are downloaded from the Application Server
  • W, the number of stages where page images are uploaded to the Application Server
Then calculate the two speeds.
For example, a customer processes 10,000 grayscale pages per hour through a four-stage workflow. Only stages that move page images to or from the Application Server count toward R and W. At an average A4 grayscale file size of 3 MB:
  • Input flow = 10,000 grayscale page images/hour = 2.8 grayscale images/s = 8.4 MB/s
  • Required write speed = 1 × 8.4 MB/s = 8.4 MB/s
  • Required read speed = 3 × 8.4 MB/s = 25.2 MB/s
To benchmark the performance of the hard disk, you can use the CrystalDiskMark tool, distributed under the MIT license.

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How long documents stay in the System

Capacity depends on how long images remain in the System before they are deleted. For example, a customer processes 100,000 grayscale images in 24 hours. Under the Service-Level Agreement, the processing time is 2 days per document. Processed documents are then stored for 2 weeks, because the customer’s ERP system runs additional checks. If it finds any discrepancies, the documents are edited in FlexiCapture and uploaded to the ERP system again. Images are therefore stored for 2 + 14 = 16 days. At an average A4 grayscale file size of 3 MB, the System accumulates 16 × 100,000 × 3 MB = 4.8 TB of data.

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Large

Use the Large configuration for more than 300,000 color pages per 24 hours. It reaches up to 3 million black-and-white pages or up to 1 million color pages in 24 hours. Every Medium recommendation applies to Large, but at this scale you have to follow all of them. Calculate the load on each part of the System and choose hardware powerful enough to carry it without overspending. Test the Internet connection and the backend connector to confirm they sustain the target performance. Plan for a 10 Gb/s network and a high-throughput FileStorage from the start. The following diagram shows one possible network architecture for the Large configuration.
Diagram of a possible Large FlexiCapture network configuration, where ABBYY FlexiCapture Clients reach two Application Servers and the Processing and Licensing Servers across 10 Gb/s switches, the Application Servers connect to File Storage at 10 Gb/s and to the Database at 1 Gb/s, and the Processing Stations link to the Customer's ERP system at 2 Gb/s and to a dedicated temp-folder hard drive at 10 Gb/s.
There are no typical system requirements at this scale. Review a tested configuration and its measured performance instead. For more information, see Test results on Huawei FusionCube 6000.

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xLarge

For volumes beyond the Large configuration, combine several independent FlexiCapture installations under a single Administration and Monitoring point. This is the xLarge configuration.