Azure outage takes down StorSimple 8100 RRS feed

  • Question

  • We have a StorSimple 8100 with about 22 TB in use locally. Last week there was an Azure outage in the West US region which resulted in our StorSimple losing connection to Azure. When that happened, our data volumes went down and all user files became inaccessible. I was told by a support engineer that it was working as designed if Azure connectivity is lost. We did have backups set to run hourly and the volume disconnection happened just after a backup started.

    To me it seems like questionable design if you have a local appliance with a copy of all your files that has to crash if it loses connectivity to Azure. One of the reasons we bought the StorSimple was because we thought we would have redundancy if there was an Azure outage. 

    I'm wondering if there is any way to prevent the local appliance volumes from going down if Azure connectivity is lost. If not, a warning would be helpful so that the volumes could be taken down gracefully instead of going down hard.

    Monday, July 23, 2018 7:04 PM

All replies

  • If cloud connectivity fails on your StorSimple production device, then depending on the state of your device, the following can occur:

    For the local data on your device: For some time, there will be no disruption and reads will continue to be served. However, as the number of outstanding IOs increases and exceeds a limit, the reads could start to fail.

    Depending on the amount of data on your device, the writes will also continue to occur for the first few hours after the disruption in the cloud connectivity. The writes will then slow down and eventually start to fail if the cloud connectivity is disrupted for several hours. (There is temporary storage on the device for data that is to be pushed to the cloud. This area is flushed when the data is sent. If connectivity fails, data in this storage area will not be pushed to the cloud, and IO will fail.)

    The StorSimple device tiers old data from the local tiers to Azure.  If the device loses connection with Azure, the data on the local disks is accessible to hosts.  However, if a block of data which is present on the cloud is requested by the host, the device retries getting the data.  If the data cannot be retrieved within 4 minutes, the volume/lun will be put in an offline state.  If the connection is established within the 4-minute period, the data is fetched from Azure and served to the host.

    If a cloud snapshot is in progress the job keeps trying to send the data to Azure and if there is a prolonged outage, the job will be cancelled after 4 hours.

    The total usable capacity includes the capacity available for data, metadata, and buffers. You can provision locally pinned volumes up to 8.5 TB on the8100 devices.Data stored in locally pinned volumes is not de-duplicated and compressed. However, snapshots of locally pinned volumes are de-duplicated. Because locally pinned volumes are fully provisioned, some existing data from tiered volumes might be pushed to the cloud during the provisioning process. You can configure alerts using this link . Suggest you to refer the FAQ section for StorSimple locally pinned volumes.


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    • Proposed as answer by Sandeep BR Friday, July 27, 2018 9:21 PM
    Friday, July 27, 2018 9:21 PM