AWS Storage Gateway, Руководство пользователя

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AWS Storage Gateway User Guide
Object Versioning Might Affect
What You See in Your File System
your file share. You can also update KMS settings for your file share by using the
UpdateNFSFileShare
or
UpdateSMBFileShare
API operation. This update applies to objects stored in the Amazon S3
buckets after the update. For more information, see Encrypting Your Data Using AWS Key Management
Service (p. 293) .
Object Versioning Might Affect What You See in Your
File System
If your Amazon S3 bucket has objects written to it by another client, your view of the S3 bucket might
not be up-to-date as a result of S3 bucket object versioning. You should always refresh your cache before
examining files of interest.
Object versioning is an optional S3 bucket feature that helps protect data by storing multiple copies of
the same-named object. Each copy has a separate ID value, for example
file1.jpg
:
ID="xxx"
and
file1.jpg
:
ID="yyy"
. The number of identically named objects and their lifetimes is controlled by
S3 lifecycle policies. For more details on these S3 concepts, see Using Versioning and Object Lifecycle
Management in the Amazon S3 Developer Guide.
When you delete a versioned object, that object is flagged with a delete marker but retained. Only an S3
bucket owner can permanently delete an object with versioning turned on.
In your file gateway, files shown are the most recent versions of objects in an S3 bucket at the time the
object was fetched or the cache was refreshed. File gateways ignore any older versions or any objects
marked for deletion. When reading a file, you read data from the latest version. When you write a file in
your file share, your file gateway creates a new version of a named object with your changes, and that
version becomes the latest version.
Your file gateway continues to read from the earlier version, and updates that you make are based on
the earlier version should a new version be added to the S3 bucket outside of your application. To read
the latest version of an object, use the RefreshCache API action or refresh from the console as described
in Refreshing Objects in Your Amazon S3 Bucket (p. 153) . We don't recommend that objects or files be
written to your file gateway S3 bucket from outside of the file share.
Use of versioned S3 buckets can greatly increase the amount of storage in S3 because each modification
to a file creates a new version. By default, S3 continues to store all of these versions unless you
specifically create a policy to override this behavior and limit the number of versions that are kept. If you
notice unusually large storage usage with object versioning enabled, check that you have your storage
policies set appropriately. An increase in the number of
HTTP 503-slow down
responses for browser
requests can also be the result of problems with object versioning.
If you enable object versioning after installing a file gateway, all unique objects are retained
(
ID=”NULL”
) and you can see them all in the file system. New versions of objects are assigned a unique
ID (older versions are retained). Based on the object's timestamp only the newest versioned object is
viewable in the NFS file system.
After you enable object versioning, your S3 bucket can't be returned to a nonversioned state. You can,
however, suspend versioning. When you suspend versioning, a new object is assigned an ID. If the same
named object exists with an
ID=”NULL”
value, the older version is overwritten. However, any version
that contains a non-
NULL
ID is retained. Timestamps identify the new object as the current one, and that
is the one that appears in the NFS file system.
ACL Permissions Aren't Working as Expected
If access control list (ACL) permissions aren't working as you expect with your SMB file share, you can
perform a test.
To do this, first test the permissions on a Microsoft Windows file server or a local Windows file share.
Then compare the behavior to your gateway's file share.
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