One aspect of data security in cloud storage is how file deletions are handled. Specifically, when file (also known as an 'object' in the cases of an object storage service like Wasabi) is deleted, what happens to the deleted file and how is the disk space previously occupied by the deleted file reallocated for storing other files.
When a file is deleted on Wasabi (either via the S3 API or the Wasabi management console), the following actions take place:
1. The file is marked as 'object delete' from an internal state perspective (the file is no longer accessible via the S3 API or from the Wasabi management console)
2. The deleted file metadata is deleted from the Wasabi database (this occurs with 24 hours after step 1).
3. The deleted file content is deleted from the Wasabi storage disk and the space previously occupied on the disk is securely overwritten via a Wasabi process known as 'compaction.' Once the secure compaction process is completed, the disk space is available for use with other files.
On a related subject, in the event that a Wasabi storage disk containing customer content fails and needs to be replaced with a new disk, Wasabi follows a similar secure process to ensure that the data on the failed disk is never accessible or recoverable. The erasure coding process used by Wasabi ensures that the disk replacement process is transparent and non-impacting to a customer (file integrity and file access is always preserved).