One or more compression cards are an optional part of any VMX-Capture deployment. They compress data on-the-fly before it is written to disk. This allows VMX-Capture to deal effectively with higher data volumes than would be possible without compression.

Different financial market protocols have different compression characteristics, and for low volume deployments it is possible to deploy VMX-Capture without a compression card.

The compression cards also move packet capture decompression tasks onto the FPGA, which speeds up these tasks and reduces the load on the server CPU.

An example of a decompression task that the cards can undertake would be speeding up the rate at which the file-reading PMUX can read compressed packet captures from disk.

The interface between the VMX-Capture software and the compression card is provided by the NoLoad software provided by Eideticom. The NoLoad software provides NVMe offload. The main function of this within VMX-Capture is to allow larger volumes of traffic to be written to disk than would otherwise be possible, and frees the VMX-Capture appliance CPU from compression and decompression related tasks, allowing more cores to be dedicated to decode, outputting to the Core Data Feed and to other stack processing tasks.

Configuring VMX-Capture compression

The capture probe has a compression setting which allows different compression types to be configured.

See Capture Probe Configuration for an example of a complete capture probe configuration which includes NoLoad compression.