Frequently Asked Questions

Frequently Asked Questions

1. How do I generate a SAS for Azure 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 name ex:myadlsaccount> --account-key <accountKey> -n <container name> --permissions dlrwac --start <today's date ex: 2021-03-26> --expiry <date greater than the current time ex:2021-03-28>

2. Why do I get EINVAL on opening a file with WRONLY or APPEND flags?

To improve performance, Cloudfuse by default enables writeback caching, which can produce unexpected behavior for files opened with WRONLY or APPEND flags, so Cloudfuse 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.

3. How to mount Cloudfuse 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.

4. Why am I not able to see the updated contents of file(s), which were updated through means other than Cloudfuse mount?

If your use-case involves updating/uploading file(s) through other means and you wish to see the updated contents on Cloudfuse mount then you need to disable kernel page-cache. -o direct_io CLI parameter is the option you need to use while mounting. Along with this, set file-cache-timeout=0 and all other libfuse caching parameters should also be set to 0. User shall be aware that disabling kernel cache can result into more calls to S3 or Azure Storage which will have cost and performance implications.