This is indicated by section named [swift-hash]. Below are the parameters that are acceptable within this section:

swift_hash_path_suffix

swift_hash_path_prefix

swift_hash_path_suffix and swift_hash_path_prefix are used as part of the hashing algorithm when determining data placement in the cluster. These values should remain secret and MUST NOT change once a cluster has been deployed.

Use only printable chars (python -c "import string; print(string.printable)").

This is indicated by section name [storage-policy:#]

Storage policies are defined here and they determine various characteristics about how objects are stored and treated. Policies are specified by name on a per container basis. The policy index is specified in the section header and is used internally. The policy with index 0 is always used for legacy containers and can be given a name for use in metadata; however, the ring file name will always be 'object.ring.gz' for backwards compatibility. If no policies are defined, a policy with index 0 will be automatically created for backwards compatibility and given the name Policy-0. A default policy is used when creating new containers when no policy is specified in the request. If no other policies are defined, the policy with index 0 will be declared the default. If multiple policies are defined, you must define a policy with index 0 and you must specify a default. It is recommended you always define a section for storage-policy:0. Aliases are not mandatory when defining a storage policy.

[storage-policy:index]

Each storage policy is defined in a separate section with an index specified in the header. Below are the parameters that are acceptable within this section:

name

Name of the storage policy. Policy names are case insensitive.

aliases

Multiple names can be assigned to one policy using aliases. All names must follow the Swift naming rules.

policy_type

Policy type can be replication or erasure_coding. Replication policy replicates the objects to specified number of replicas. Erasure coding uses PyECLib API library for encode/decode operations. Please refer to Swift documentation for details on how erasure coding is implemented.

ec_type

This parameter must be chosen from the list of EC backends supported by PyECLib.

ec_num_data_fragments

This parameter is specific to 'erasure coding' policy_type only. It defines the number of fragments that will be comprised of data.

ec_num_parity_fragments

This parameter is specific to 'erasure coding' policy_type only. It defines the number of fragments that will be comprised of parity.

ec_object_segment_size

This parameter is specific to 'erasure coding' policy_type only. It defines the amount of data that will be buffered up before feeding a segment into the encoder/decoder. The default value is 1048576.

Examples:

[storage-policy:0]

name = Policy-0

default = yes

policy_type = replication

aliases = yellow, orange

[storage-policy:1]

name = silver

policy_type = replication

[storage-policy:2]

name = deepfreeze10-4

aliases = df10-4

policy_type = erasure_coding

ec_type = liberasurecode_rs_vand

ec_num_data_fragments = 10

ec_num_parity_fragments = 4

ec_object_segment_size = 1048576

This is indicated by section name [swift-constraints]. This section sets the basic constraints on data saved in the swift cluster. These constraints are automatically published by the proxy server in responses to /info requests. Below are the parameters that are acceptable within this section:

max_file_size

max_file_size is the largest "normal" object that can be saved in the cluster. This is also the limit on the size of each segment of a "large" object when using the large object manifest support. This value is set in bytes. Setting it to lower than 1MiB will cause some tests to fail. It is STRONGLY recommended to leave this value at the default (5 * 2**30 + 2).

max_meta_name_length

max_meta_name_length is the max number of bytes in the utf8 encoding of the name portion of a metadata header.

max_meta_value_length

max_meta_value_length is the max number of bytes in the utf8 encoding of a metadata value.

max_meta_count

max_meta_count is the max number of metadata keys that can be stored on a single account, container, or object.

max_meta_overall_size

max_meta_overall_size is the max number of bytes in the utf8 encoding of the metadata (keys + values).

max_header_size

max_header_size is the max number of bytes in the utf8 encoding of each header. Using 8192 as default because eventlet uses 8192 as max size of header line. This value may need to be increased when using identity v3 API tokens including more than 7 catalog entries.

extra_header_count

By default the maximum number of allowed headers depends on the number of max allowed metadata settings plus a default value of 36 for swift internally generated headers and regular http headers. If for some reason this is not enough (custom middleware for example) it can be increased with the extra_header_count constraint.

max_object_name_length

max_object_name_length is the max number of bytes in the utf8 encoding of an object name.

container_listing_limit

container_listing_limit is the default (and max) number of items returned for a container listing request.

account_listing_limit

account_listing_limit is the default (and max) number of items returned for an account listing request.

max_account_name_length

max_account_name_length is the max number of bytes in the utf8 encoding of an account name.

max_container_name_length

max_container_name_length is the max number of bytes in the utf8 encoding of a container name.

valid_api_versions

By default, all REST API calls should use "v1" or "v1.0" as the version string, for example "/v1/account". This can be manually overridden to make this backward-compatible, in case a different version string has been used before. Use a comma-separated list in case of multiple allowed versions, for example valid_api_versions = v0,v1,v2. This is only enforced for account, container and object requests. The allowed api versions are by default excluded from /info.

auto_create_account_prefix

auto_create_account_prefix specifies the prefix for system accounts, such as those used by the object-expirer, and container-sharder. Default is ".".