Each SwarmNFS export you specify presents the named objects that are stored within a Swarm bucket. For manageability, the exact objects that a client sees when connected to SwarmNFS is filtered, and virtual hierarchies are presented as much as possible.
Note
Listing delay — Objects created in Swarm natively (not via SwarmNFS) can take up to 5 minutes plus the Search Feed's Batch Timeout to appear in SwarmNFS listings, because they must be indexed by Elasticsearch. For best listing performance, lower the search feed's Batch Timeout to 1 or 0 (recommended).
Listing limit — How many entries are returned in a folder listing is limited to the value configured in Elasticsearch for "index.max_result_window". SwarmNFS will allow new files to be created even if the number would exceed "index.max_result_window", but, over time, the number of entries listed will fall back down to that configured maximum. See Configuring Elasticsearch.
Exclusive opens — SwarmNFS supports exclusive opens of a file (O_EXCL and O_CREATE) but does not support exclusive reopens (EXCLUSIVE4).
Named Object Listings
To present named object listings as if they were in a traditional file system, SwarmNFS creates a simulation: it translates each forward slash (/) in any object name into a traditional directory delimiter. SwarmNFS then presents a view of objects at the simulated directory level. For example, suppose these named objects exist in the bucket “AcmeBucket”:
/Sales/Leads/campaigns/2016/Jan/list.xls /Sales/Leads/campaigns/2016/Feb/list.xls /Sales/Leads/campaigns/addword.xls /Sales/Leads/campaigns/partners.xls
Note
By default, for a client request for a bucket-level listing, SwarmNFS provides a simulated view of the first level of contents within the bucket:
Each client request to open a specific directory level within the bucket (such as /Sales/Leads/campaigns) returns a new listing for that context:
If the user requests a listing for a file (such as Sales/Leads/campaigns/addword.xls) then only that single file would be returned.
If an end user creates a new directory (such as AcmeBucket/Sales/Leads/campaigns/2016/Mar), SwarmNFS creates a new empty object with Directory attribute metadata, which marks it as a simulated directory.
Important
To delete a directory, end users must first remove any files within it.
To rename a directory, end users must create a directory with the new name, move the files into it, and then delete the directory with the old name. (NFS-607)
Keep in mind that simulated directory objects only exist to support the expectations of end users and applications: objects can be written to a new virtual directory just by including it in the pathname.