Write performance with barrier=0 and cache read only


  • I am using Linux with ext4 and premium storage.

    According to documentation i have enabled `barrier=0` in my /etc/fstab for the premium storage disk and enabled cache = read only as its a read heavy disk.

    My write operations are saturating at 60 MB/s, is there anything that i need to do to get better write performance ?

    Saturday, January 7, 2017 4:14 PM

All replies

  • Hi Parth,

    Thank you for contacting Microsoft forums. We are pleased to answer your query.

    Could you confirm if the storage account and the Linux VM are in the same region. You should make sure you attach disks from storage accounts residing in the same region as your Linux VM to minimise network latency.

    Also, if you have attached multiple disks from your Premium Storage account you can consider configuring Logical Volume Manager on your VM. If you go for the striped logical volume it would utilise all the attached disks for read/write operations resulting in much better performance.

    I hope that the reply will assist you in getting your query addressed. In case you require further assistance, please do reply to the thread as we are always available to your queries.


    Md. Shihab


    Please remember to click "Mark as Answer" on the post that helps you as this can be beneficial to other community members reading the thread. And vote as helpful.

    • Edited by Md Shihab Sunday, January 8, 2017 5:22 AM added link
    Sunday, January 8, 2017 5:21 AM
  • Hi - What is the VM size you are using? Also, can you please clarify how you measure the 60 MB/sec disk saturation? Is it done using a benchmarking tool like FIO?

    Sunday, January 8, 2017 6:45 AM
  • Hi,

    Yes i am using the same region for storage and VM.
    As this is the only disk on my system (A Standard F8s) i have not setup LVM

    Monday, January 9, 2017 10:57 AM
  • I have used both scientific and non scientific ways

    Scientific : iotop, FIO
    Non - Scientific : Download 10Gb file from Azure blob storage and AWS S3 using azure cli and s3cmd respectively. 

    Every time i see this figure of ~60MBps 

    Monday, January 9, 2017 10:59 AM
  • Thanks.

    (1) Could you please run the following command:

          nslookup <<your storage account>>

       and provide the value of "Name".

    (2) Also, please share the config used for FIO test

    Wednesday, January 11, 2017 7:02 AM