What is a VDF?
- VDF stands for "Virus Definition File" and is created by the Avira Virus Lab.
- The VDF is part of almost every Avira product and contains information (fingerprint, detection rules) to identify malware in files.
- The VDF is updated regularly (currently up to 8 times a day).
- The first VDF started back in the 90s with a single container file (monoVDF). The growth in malware resulted in an increase in the size of the VDF, with customers having to update the entire VDF file even in the event of small changes. The answer to this was the iVDF which included 4 VDF container files that could be updated separately.
- This VDF generation was superseded by nVDF, which had up to 32 container files. With this mechanism, all stored data in the VDF can be downloaded redundantly.
- Recent years have seen an increase in the VDF loading time as more and more detections have been added to the VDF. As a result, xVDF was created which includes any number of VDF container files and supports faster loading of VDF files.
What is an xVDF?
xVDF stands for "e(x)tended Virus Definition File" and it succeeds nVDF.
What are the benefits of xVDFs?
With the xVDF mechanism, the update volume of VDF files is minimized. This allows us to keep the VDF files as small as possible. Another improvement is the VDF loading time. CPU resource consumption when loading the VDF files is also reduced.
How do we achieve a smaller download volume with xVDF?
Our reviewer says: "this number" is best replaced with "the number of VDF files" and the mentioning of "the number of VDF files" after that is best replaced with "this number" - just so the reader doesn't get confused. For our Android product, we start with 32 xVDFs. As more VDF files are available, new VDF data can be distributed as independent VDF files.
How do we achieve faster loading of the xVDF?
xVDF update files are downloaded and merged into one single VDF file locally on the client machine (local.vdf). Instead of loading and merging the downloaded VDF files on scan startup, the scan engine just loads the single cache VDF file which was created after an xVDF update.
What are the xVDF file names for our Windows products?
With xVDF the file name prefix for Windows products changed to xbv, followed by a number. The filename extension is .vdf.
What are the xVDF file names for our Android product?
With xVDF for Android, the file name prefix is xba followed by a number. The file name extension is .vdf.
- Android xVDF