I have a number of files that I transferred into Azure Blob Storage via the Azure Data Factory. Unfortunately, this tool doesn't appear to set the Content-MD5 value for any of the values, so when I pull that value from the Blob Storage API, it's empty.
I'm aiming to transfer these files out of Azure Blob Storage and into Google Storage. The documentation I'm seeing for Google's Storagetransfer service at https://cloud.google.com/storage/transfer/reference/rest/v1/TransferSpec#HttpData indicates that I can easily initiate such a transfer if I supply a list of the files with their URL, length in bytes and an MD5 hash of each.
Well, I can easily pull the first two from Azure Storage, but the third doesn't appear to automatically get populated by Azure Storage, nor can I find any way to get it to do so.
Unfortunately, my other options look limited. In the possibilities so far:
- Download file to local machine, determine the hash and update the Blob MD5 value
- See if I can't write an Azure Functions app in the same region that can calculate the hash value and write it to the blob for each in the container
- Use an Amazon S3 egress from Data Factory and then use Google's support for importing from S3 to pull it from there, per https://cloud.google.com/storage/transfer/reference/rest/v1/TransferSpec#AwsS3Data but this really seems like a waste of bandwidth (and I'd have to set up an Amazon account).
Ideally, I want to be able to write a script, hit go and leave it alone. I don't have the fastest download rate from Azure, so #1 would be less than desireable as it'd take a long time.
Have any other approaches?
Did you think about using Azure Data Factory custom activity support that is used for data transformation? On back-end, you can use Azure Batch for downloading, updating and uploading your files into Google Storage, if you go with ADF custom activity.
We have migrated about 3TB files from Azure to Google Storage. We have started a cheap Linux server with a few TB local disk in the Google Computing Engine. Transferred the the Azure files to the local disk by blobxfer, then copied the files from the local disk to the Google Storage by gsutil rsync (gsutil cp works too).
You can use other tools to transfer files from Azure, you may even start the Windows server in the GCE and use gsutils on Windows.
It has taken a few days, but was simple and straightforward.
I know it's a bit late to answer this question for you, but it might help others who all are trying to migrate data from Azure Blob Storage to Google Cloud Storage
Google Cloud Storage and Azure Blob Storage, both platforms being storage services, does not have a command line interface, where we can simply go and run transfer commands. For that, we need an intermediate compute instance which would actually be able to run the required commands. We will follow the steps below in order to achieve the Cloud to Cloud transfer.
First and foremost, create a Compute Instance in Google Cloud Platform. You needn't create a computationally powerful instance, all you need is a Debian-10GB machine with 2-core CPU and 4 GB of memory.
In the early days, you would have downloaded the data to the Compute Instance in GCP and then move it further to Google Cloud Storage. But now with the introduction of gcsfuse we can simply mount a Google Storage Account as a File System.
Once the compute instance is created, simply login to that instance using SSH from Google Console and install the following packages.
Install Google Cloud Storage Fuse
export GCSFUSE_REPO=gcsfuse-`lsb_release -c -s`
echo "deb http://packages.cloud.google.com/apt $GCSFUSE_REPO main" | sudo tee /etc/apt/sources.list.d/gcsfuse.list
curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
sudo apt-get update -y
sudo apt-get install gcsfuse -y
# Create local folder
mkdir local_folder_name
# Mount the Storage Account as a bucket
gcsfuse <bucket_name> <local_folder_path>
Install Azcopy
wget https://aka.ms/downloadazcopy-v10-linux
tar -xvf downloadazcopy-v10-linux
sudo cp ./azcopy_linux_amd64_*/azcopy /usr/bin/
Once these packages are installed, the next step is to create the Shared Signature Access key. If you have Azure Blob Storage Explorer, just right click on the storage account name in the directory tree and Select Generate Shared Access Signature
Now you will have to create a URL to your blob objects. To achieve this, simply right-click on any of your blob object, select Properties and copy the URL from the dialogue box.
Your final Url should look like.
<https://URL_to_file> + <SAS Token>
https://myaccount.blob.core.windows.net/sascontainer/sasblob.txt?sv=2015-04-05&st=2015-04-29T22%3A18%3A26Z&se=2015-04-30T02%3A23%3A26Z&sr=b&sp=rw&sip=168.1.5.60-168.1.5.70&spr=https&sig=Z%2FRHIX5Xcg0Mq2rqI3OlWTjEg2tYkboXr1P9ZUXDtkk%3D
Now, use following command to start copying the files from Azure to GCP storage.
azcopy cp --recursive=true "<-source url->" "<-destination url->"
If in case, your job fails you can list your jobs using:
azcopy jobs list
and to resume failed jobs:
azcopy jobs resume jobid <-source sas->
You can collate all the steps into one bash, leave it running till your data transfer is complete.
And that's all! I hope it help others
