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Quick Comparer to Compare Name and Size of local and remote file on Amazon S3 / Google Storage


Bucket Explorer provides data consistency during Upload and Download. To ensure files are uploaded without corruption, it calculates and sends a hash of every file to Amazon S3 or Google Storage.
For Download, it calculates the hash of downloaded file and compares it with the ETAG/Size of Object. When re-uploading a file, it is only uploaded when the hash of the file is different from the ETAG/Size of Object. Same thing happens at download. The file is downloaded only when it is either new or its hash is different from the ETAG/Size of Object.

About Quick Comparer:

Bucket Explorer supports S3 operations with an option to choose any of these comparisons (Name and Size & Name and Hash). Whatever comparison you choose, the file will be uploaded/ downloaded if the Hash/Size is different. It will also prompt you for any of the Actions [Overwrite, Skip, Overwrite All, and Skip All] to be performed with the files, if it already exists. Quick Comparer is an important feature added in Bucket Explorer which compares Name and Size instead of comparing Name and Hash of the file. This comparison makes incremental backup faster.

During ‘Name & Hash’, Bucket Explorer calculates the Hash of every file and compares it with the ETAG of file in Amazon S3 or Google Storage. For this comparison, it sends a separate request for every file to collect the ETAG values. Otherwise, it prepares a list of all objects with their Name and Size with a minimum request (1000 Object details in a single request). Thus, it does not send a separate request for each file.

Follow the steps below to use Quick Comparer option:
  1. Run Bucket Explorer.
  2. Select a bucket.
  3. Perform one of the following actions on bucket:
  4. Upload or Download
  5. It will open a dialog box entitled “Select Option for Queue”.
  6. It will ask for “Action Type” and “Comparison Type”.
  7. In action type, you will have three options:
    1. Overwrite All: To Overwrite All Files.
    2. Skip All: To Skip all files.
    3. Ask for Action: To prompt for action when it is needed.
  8. In Comparison Type, you will have Two Options:
    1. Compare Name and Size
    2. Compare Name and Hash
  9. Click on ‘Start’ button and it will start the operation in Queue.

Save Quick Comparer Options for each queue operation :
You can set quick Compare option in Tools -> "Advance Preferences" option in Bucket explorer menu bar. You can set quick compare option as you wish in the Queue Option settings. When you checked the "Remember for each queue operaton" option then this panel will not prompt you for it and retrive these setting for next all queue operation.

Single File operation :
If a single file is chosen for upload/download, quick comparer window will not be opened. It notifies the user with a balloon tool tip at the lower left corner about the completion of the operation. By default, the selected operation is performed by comparing name and hash of file.

Identical-Skipped at Quick Comparer Queues :
If identical files have been chosen to upload or download then these files will not be queued for processing, It will directly be added in Identical-Skipped list.

Example :
Suppose you have 3000 files (more than 10 MB of size for each file) to upload. After uploading 3000 files, some of the files are modified and some new files are added. To upload new and modified files, choose Name and Size. Files will be uploaded more quickly than upload with Name and Hash.

Quick Comparer also asks for the action to be performed if it finds a file that already exists.
  1. If you select Skip All , it will skip the file to upload.
  2. If you select Overwrite All , it will re-upload the file only if the hash is different.
  3. If you select Ask for Action , it will ask what to do with the file.
  4. You can choose Overwrite or Skip Action. If you want Bucket Explorer not to ask action for the next file, you can also choose Overwrite All or Skip All instead of 'Ask For Action'.
NOTE: If you are uploading the files for the first time, you will not get much difference in both comparer options. But if you make incremental upload/ download, you should choose ‘Compare Name and Size’ for fast processing. In incremental processing, Bucket Explorer identifies the files which need to be uploaded / downloaded exactly. It processes the file whether it is new or modified. To identify these files, Bucket Explorer uses one of the Comparer Option. If Name and Hash option is selected, Bucket Explorer calculates the hash and matches it with the ETAG of Object and if Name and Size option is selected, it compares the name and size of the file with the name and size of Amazon S3 or Google Storage Object.
Quick Comparer works with Upload , Download , Copy  and Move  in Queue .

Related Topic:

Bucket Explorer Amazon S3:

Bucket Explorer Google Storage: