Changing the Block Size Limit

The Block Size Limit

Azure's Blob Storage has a block size limit of 50,000 blocks. Depending on the default block size, this can create an issue when uploading a large file via SFTP Gateway.

In version 3.2.1 and below, there was a default block size of 4 MB per block. This resulted in a file size limit of about 195 GB. In version 3.3.0, we have introduced a larger default block size limit, as well as a configuration option to change the block size.

The default block size limit in version 3.3.0 is now set to 100 MB per block, which results in a file size limit of about 4.75 TB.

Configuring the Block Size Limit

To configure the default block size limit, SSH into your VM and edit the file /opt/sftpgw/application.properties, to add the following property:

features.file-system.azure.block-size-mb=

This sets the block size limit to the number you add to the end. 4 is the lowest value you can set and 4000 is the highest.

So, if you would like to change the block size limit to the maximum, 4000 MB, you would add the following property:

features.file-system.azure.block-size-mb=4000

To apply your changes, restart the Java service:

sudo service sftpgw-admin-api restart