Resizing chunk files in Syncrify

File comparison in Syncrify is done in 3 stages:

1. Matching size and date of the file on both ends
2. Matching MD5 checksum of the file
3. Matching blocks

Block matching (Stage 3) occurs if a match is not found using the first two methods. This is the most time consuming stage. To reduce this time, Syncrify splits a large file into smaller chunks of 1TB * each. For example, the original file is 10TB, Syncrify will try to split it up in 10 files of 1TB each. Once these files are split, MD5 checksum is computed to determine the chunks that match, hence avoiding block matching on the entire file.

The chunk size is set to 1TB* by default and is configurable. Following steps demonstrate how to configure this value:

* Prior to v3.1 the default chunk size was 8GB

Microsoft Windows

• Locate the SyncrifyData folder on the client's machine. By default this is in C:\ProgramData directory.
• In the SyncrifyData directory, create a file named client.properties, if it does not exist.
• Open this file with a text editor, such as notepad. Add the following line:
  max.file.part=107374182400
• This sets the chunk size to 100GB. (107374182400 is the number of bytes in 100GB)
  
• Save the file, and close Syncrify Client. Additionally, restart the Backup Monitor Service in the services page in Windows.
  

Linux

Specify a -D parameter as a command line argument. This will set the chunk size to 100GB