About Storage Analytics Logging

The following types of authenticated requests are logged:

• Successful requests
  
  
• Failed requests, including timeout, throttling, network, authorization, and other errors
  
  
• Requests using a Shared Access Signature (SAS), including failed and successful requests
  
  
• Requests to analytics data
  
  

Requests made by Storage Analytics itself, such as log creation or deletion, are not logged. A full list of the logged data is documented in the Storage Analytics Logged Operations and Status Messages and Storage Analytics Log Format topics.

The following types of anonymous requests are logged:

• Successful requests
  
  
• Server errors
  
  
• Timeout errors for both client and server
  
  
• Failed GET requests with error code 304 (Not Modified)
  
  

All other failed anonymous requests are not logged. A full list of the logged data is documented in the Storage Analytics Logged Operations and Status Messages and Storage Analytics Log Format topics.

All logs are stored in block blobs in a container named $logs, which is automatically created when Storage Analytics is enabled for a storage account. The $logs container is located in the blob namespace of the storage account, for example: http://<accountname>.blob.core.windows.net/$logs. This container cannot be deleted once Storage Analytics has been enabled, though its contents can be deleted.

Note

The $logs container is not displayed when a container listing operation is performed, such as the ListContainers method. It must be accessed directly. For example, you can use the ListBlobs method to access the blobs in the $logs container. As requests are logged, Storage Analytics will upload intermediate results as blocks. Periodically, Storage Analytics will commit these blocks and make them available as a blob.

Duplicate records may exist for logs created in the same hour. You can determine if a record is a duplicate by checking the RequestId and Operation number.

Log Naming Conventions

Each log will be written in the following format:

<service-name>/YYYY/MM/DD/hhmm/<counter>.log

The following table describes each attribute in the log name:

 

Attribute	Description
<service-name>	The name of the storage service. For example: blob, table, or queue
YYYY	The four digit year for the log. For example: 2011
MM	The two digit month for the log. For example: 07
DD	The two digit day for the log. For example: 31
hh	The two digit hour that indicates the starting hour for the logs, in 24 hour UTC format. For example: 18
mm	The two digit number that indicates the starting minute for the logs. Note This value is unsupported in the current version of Storage Analytics, and its value will always be 00.
<counter>	A zero-based counter with six digits that indicates the number of log blobs generated for the storage service in an hour time period. This counter starts at 000000. For example: 000001

The following is a complete sample log name that combines the above examples:

blob/2011/07/31/1800/000001.log

The following is a sample URI that can be used to access the above log:

https://<accountname>.blob.core.windows.net/$logs/blob/2011/07/31/1800/000001.log

When a storage request is logged, the resulting log name correlates to the hour when the requested operation completed. For example, if a GetBlob request was completed at 6:30PM on 7/31/2011, the log would be written with the following prefix: blob/2011/07/31/1800/

Log Metadata

All data in the $logs container can be accessed by using the Blob service APIs, including the .NET APIs provided by the Windows Azure managed library. The storage account administrator can read and delete logs, but cannot create or update them. Both the log’s metadata and log name can be used when querying for a log. It is possible for a given hour’s logs to appear out of order, but the metadata always specifies the timespan of log entries in a log. Therefore, you can use a combination of log names and metadata when searching for a particular log.

Concepts

Other Resources