Blobfuse2‐FAQ

Frequently Asked Questions

• How do I generate a SAS with permissions for rename? az cli has a command to generate a sas token. Open a command prompt and make sure you are logged in to az cli. Run the following command and the sas token will be displayed in the command prompt. az storage container generate-sas --account-name --account-key -n --permissions dlrwac --start <today's date ex: 2021-03-26> --expiry
• Why do I get EINVAL on opening a file with WRONLY or APPEND flags? To improve performance, Blobfuse2 by default enables writeback caching, which can produce unexpected behavior for files opened with WRONLY or APPEND flags, so Blobfuse2 returns EINVAL on open of a file with those flags. Either use disable-writeback-caching to turn off writeback caching (can potentially result in degraded performance) or ignore-open-flags (replace WRONLY with RDWR and ignore APPEND) based on your workload.
• How to mount blobfuse2 inside a container? Refer to 'docker' folder in this repo. It contains a sample 'Dockerfile'. If you wish to create your own container image, try 'buildandruncontainer.sh' script, it will create a container image and launch the container using current environment variables holding your storage account credentials.
• Why am I not able to see the updated contents of file(s), which were updated through means other than Blobfuse2 mount? If your use-case involves updating/uploading file(s) through other means and you wish to see the updated contents on Blobfuse2 mount then you need to disable kernel page-cache. --disable-kernel-cache CLI parameter is the option you need to use while mounting. Along with this, set file-cache-timeout=0. User shall be aware that disabling the cache will result into more calls to Azure Storage which will have cost and performance implications.