blobfuse2-faq.yml

### YamlMime:FAQ
metadata:
  title: Frequently asked questions - BlobFuse | Microsoft Docs
  description: This article provides a list of frequently asked questions (FAQ) for Blob. 
  ms.topic: faq
  ms.service: azure-blob-storage
  ms.date: 1/29/2026
  ms.author: normesta
  author: normesta
title: BlobFuse frequently asked questions
summary: |
  This article provides a list of frequently asked questions (FAQ) for BlobFuse.</br></br>

sections:
  - name: FAQ
    questions:
      - question: |
          How do I generate a SAS with permissions for rename?
        answer: |
          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>`
      - question: |
          Why do I get EINVAL on opening a file with WRONLY or APPEND flags?
        answer: |
          To improve performance, BlobFuse by default enables writeback caching, which can produce unexpected behavior for files opened with WRONLY or APPEND flags, so BlobFuse 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.
      - question: |
          How to mount BlobFuse inside a container?
        answer: 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. |
      - question: |
          Why am I not able to see the updated contents of file(s), which were updated through means other than BlobFuse mount?
        answer: If your use-case involves updating and uploading file(s) through other means and you wish to see the updated contents on BlobFuse 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. |
additionalContent: |

  ## Next steps
  
  You can learn more about Azure Blob Storage by visiting the following links:

  - [Introduction to Azure Storage](../common/storage-introduction.md)
  - [What is Azure Blob Storage](storage-blobs-overview.md)