er.h File Reference

encoding and redundancy library More...

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Functions
int	ER_Init (const char *conf_file)
int	ER_Finalize (void)
int	ER_Create_Scheme (MPI_Comm comm, const char *failure_domain, int data_blocks, int erasure_blocks)
kvtree *	ER_Config (const kvtree *config)
int	ER_Free_Scheme (int scheme_id)
int	ER_Create (MPI_Comm comm_world, MPI_Comm comm_store, const char *name, int direction, int scheme_id)
int	ER_Add (int set_id, const char *file)
int	ER_Dispatch (int set_id)
int	ER_Test (int set_id)
int	ER_Wait (int set_id)
int	ER_Free (int set_id)

Function Documentation

ER_Add()

int ER_Add	(	int	set_id,
		const char *	file
	)

adds file to specified set id

Parameters

[in]	set_id	[IN] - set id to add file to
[in]	file	[IN] - path to file

ER_Config()

kvtree* ER_Config

(

const kvtree *

config

)

Get/set ER configuration values.

The following configuration options can be set (type in parenthesis):

• "DEBUG" (int) - if non-zero, output debug information from inside ER.
• "SETSIZE" (int) - set size for ER to use.
• "MPI_BUF_SIZE" (byte count [IN], int [OUT]) - MPI buffer size to chunk file transfer. Must not exceed INT_MAX.

Symbolic names ER_KEY_CONFIG_FOO are defined in er.h and should be used instead of the strings whenever possible to guard against typos in strings.

Returns

If config != NULL, then return config on success. If config == NULL (you're querying the config) then return a new kvtree on success, which must be kvtree_delete()ed by the caller. NULL on any failures.

Parameters

config

The new configuration. If config == NULL, then return a new kvtree with all the configuration values.

Parameters

[in]

config

[IN] - kvtree of options

ER_Create()

int ER_Create	(	MPI_Comm	comm_world,
		MPI_Comm	comm_store,
		const char *	name,
		int	direction,
		int	scheme_id
	)

create a named set, and specify whether it should be encoded, recovered, or unencoded

Parameters

[in]	comm_world	[IN] - communicator of processes participating in operation
[in]	comm_store	[IN] - communicator of processes that share access to storage holding files
[in]	name	[IN] - name of operation
[in]	direction	[IN] - operation to execute: one of ER_DIRECTION constants
[in]	scheme_id	[IN] - redundancy scheme to be applied to this set

ER_Create_Scheme()

int ER_Create_Scheme	(	MPI_Comm	comm,
		const char *	failure_domain,
		int	data_blocks,
		int	erasure_blocks
	)

defines a redundancy scheme, returns scheme id as integer

Parameters

[in]	comm	[IN] - communicator of processes participating in scheme
[in]	failure_domain	[IN] - processes with same value of failure_domain are assumed to fail at the same time
[in]	data_blocks	[IN] - number of original data blocks
[in]	erasure_blocks	[IN] - number of erasure blocks to be generated

ER_Dispatch()

int ER_Dispatch

(

int

set_id

)

initiate encode/rebuild operation on specified set id

Parameters

[in]

set_id

[IN] - set id to dispatch

ER_Finalize()

int ER_Finalize

(

void

)

ER_Free()

int ER_Free

(

int

set_id

)

free internal resources associated with set id

ER_Free_Scheme()

int ER_Free_Scheme

(

int

scheme_id

)

Parameters

[in]

scheme_id

[IN] - release resources associated with specified scheme id

ER_Init()

int ER_Init

(

const char *

conf_file

)

Parameters

[in]

conf_file

[IN] - path to configuration file (can be NULL for default)

ER_Test()

int ER_Test

(

int

set_id

)

tests whether ongoing dispatch operation to finish, returns 1 if done, 0 otherwise

ER_Wait()

int ER_Wait

(

int

set_id

)

wait for ongoing dispatch operation to finish