wrench::SimpleStorageService

class SimpleStorageService : public wrench::StorageService

A storage service that provides direct access to some storage resources (e.g., one or more disks). An important (configurable) property of the storage service is SimpleStorageServiceProperty::BUFFER_SIZE (see documentation thereof), which defines the buffer size that the storage service uses. Specifically, when the storage service receives/sends data from/to the network, it does so in a loop over data “chunks”, with pipelined network and disk I/O operations. The smaller the buffer size the more “fluid” the model, but the more time-consuming the simulation. A large buffer size, however, may lead to less realistic simulations. At the extreme, an infinite buffer size would correspond to fully sequential executions (first a network receive/send, and then a disk write/read). Setting the buffer size to “0” corresponds to a fully fluid model in which individual data chunk operations are not simulated, thus achieving both accuracy (unless one specifically wishes to study the effects of buffering) and quick simulation times. For now, setting the buffer size to “0” is not implemented. The default buffer size is 10 MiB (note that the user can always declare a disk with arbitrary bandwidth in the platform description XML).

Subclassed by wrench::SimpleStorageServiceBufferized, wrench::SimpleStorageServiceNonBufferized

Public Functions

~SimpleStorageService() override

Destructor.

inline void createFile(const std::shared_ptr<DataFile> &file)

Create a file at the storage service (in zero simulated time)

Parameters:

file – a file

inline void createFile(const std::shared_ptr<DataFile> &file, const std::string &path)

Create a file at the storage service (in zero simulated time)

Parameters:

  • file – a file

  • path – a path

virtual void createFile(const std::shared_ptr<FileLocation> &location) override

Create a file at the storage service (in zero simulated time)

Parameters:

location – a location

void createFile(const std::shared_ptr<FileLocation> &location) = 0

Create a file at the storage service (in zero simulated time)

Parameters:

location – a location

inline void deleteFile(const std::shared_ptr<DataFile> &file)

Delete a file at the storage service (incurs simulated overheads)

Parameters:

file – a file

inline void deleteFile(const std::shared_ptr<DataFile> &file, const std::string &path)

Delete a file at the storage service (incurs simulated overheads)

Parameters:

  • file – a file

  • path – a path

inline void deleteFile(const std::shared_ptr<FileLocation> &location)

Delete a file at the storage service (incurs simulated overheads)

Parameters:

location – a location

void deleteFile(S4U_CommPort *answer_commport, const std::shared_ptr<FileLocation> &location, bool wait_for_answer)

Delete a file on the storage service.

Parameters:

  • answer_commport – the answer commport to which the reply from the server should be sent

  • location – the location to delete

  • wait_for_answer – whether this call should

virtual std::string getBaseRootPath() override

Get the base root path. Note that if this service has multiple mount points, this method will throw an exception.

Returns:

inline virtual sg_size_t getBufferSize() const override

Determine the storage service’s buffer size.

Returns:

a size in bytes

simgrid::s4u::Disk *getDiskForPathOrNull(const std::string &path)

Gets the disk that stores a path.

Parameters:

path – a path

Returns:

a disk, or nullptr if path is invalid

virtual double getFileLastWriteDate(const std::shared_ptr<DataFile> &file, const std::string &path = "/") override

Get a file’s last write date at a location (in zero simulated time)

Parameters:

  • file – the file

  • path – the path

Returns:

the file’s last write date, or -1 if the file is not found or if the path is invalid

virtual double getFileLastWriteDate(const std::shared_ptr<FileLocation> &location) override

Get a file’s last write date at a the storage service (in zero simulated time)

Parameters:

location – a location

Returns:

a date in seconds, or -1 if the file is not found

inline virtual std::shared_ptr<simgrid::fsmod::FileSystem> getFileSystem() override

Retrieve the simple storage service’s file system object.

Returns:

A file system

virtual std::string getMountPoint() override

Get the storage service’s mount point.

Returns:

the mount points

virtual std::set<std::string> getMountPoints() override

Get the set of mount points.

Returns:

the set of mount points

virtual unsigned long getTotalFilesZeroTime() override

Return current total number of files (in zero simulation time) for IO tracing purposes.

Returns:

total number of files

virtual sg_size_t getTotalFreeSpaceZeroTime() override

Return current total free space from all mount point (in zero simulation time) for IO tracing purpose.

Returns:

total free space in bytes

virtual sg_size_t getTotalSpace() override

Get the total static capacity of the storage service (in zero simulation time)

Returns:

capacity of the storage service in bytes

inline bool hasFile(const std::shared_ptr<DataFile> &file)

Determines whether a file is present at the storage service (in zero simulated time)

Parameters:

file – a file

Returns:

true if the file is present, false otherwise

inline bool hasFile(const std::shared_ptr<DataFile> &file, const std::string &path)

Determines whether a file is present at the storage service (in zero simulated time)

Parameters:

  • file – a file

  • path – a path

Returns:

true if the file is present, false otherwise

virtual bool hasFile(const std::shared_ptr<FileLocation> &location) override

Determines whether the storage service has the file. This doesn’t simulate anything and is merely a zero-simulated-time data structure lookup. If you want to simulate the overhead of querying the StorageService, instead use lookupFile().

Parameters:

location – a location

Returns:

true if the file is present, false otherwise

bool hasFile(const std::shared_ptr<FileLocation> &location) = 0

Determines whether a file is present at the storage service (in zero simulated time)

Parameters:

location – a location

Returns:

true if the file is present, false otherwise

bool hasMountPoint(const std::string &mp)

Checked whether the storage service has a particular mount point.

Parameters:

mp – a mount point

Returns:

true whether the service has that mount point

bool hasMultipleMountPoints()

Determine whether the storage service has multiple mount points.

Returns:

true if multiple mount points, false otherwise

inline virtual bool isBufferized() const override

Determine whether the storage service is bufferized.

Returns:

true if bufferized, false otherwise

inline bool lookupFile(const std::shared_ptr<DataFile> &file)

Lookup whether a file exists on the storage service (incurs simulated overheads)

Parameters:

file – a file

Returns:

true if the file is present, or false

inline bool lookupFile(const std::shared_ptr<DataFile> &file, const std::string &path)

Lookup whether a file exists on the storage service (incurs simulated overheads)

Parameters:

  • file – a file

  • path – a path

Returns:

true if the file is present, or false

inline bool lookupFile(const std::shared_ptr<FileLocation> &location)

Lookup whether a file exists at a location on the storage service (incurs simulated overheads)

Parameters:

location – a location

Returns:

true if the file is present, or false

bool lookupFile(S4U_CommPort *answer_commport, const std::shared_ptr<FileLocation> &location)

Asks the storage service whether it holds a file.

Parameters:

  • answer_commport – the answer commport to which the reply from the server should be sent

  • location – the location to lookup

Returns:

true if the file is present, false otherwise

inline void readFile(const std::shared_ptr<DataFile> &file)

Read a file at the storage service (incurs simulated overheads)

Parameters:

file – a file

inline void readFile(const std::shared_ptr<DataFile> &file, const std::string &path)

Read a file at the storage service (incurs simulated overheads)

Parameters:

  • file – a file

  • path – a path

inline void readFile(const std::shared_ptr<DataFile> &file, const std::string &path, sg_size_t num_bytes)

Read a file at the storage service (incurs simulated overheads)

Parameters:

  • file – a file

  • path – a path

  • num_bytes – a number of bytes to read

inline void readFile(const std::shared_ptr<DataFile> &file, sg_size_t num_bytes)

Read a file at the storage service (incurs simulated overheads)

Parameters:

  • file – a file

  • num_bytes – a number of bytes to read

inline void readFile(const std::shared_ptr<FileLocation> &location)

Read a file at the storage service (incurs simulated overheads)

Parameters:

location – a location

inline void readFile(const std::shared_ptr<FileLocation> &location, sg_size_t num_bytes)

Read a file at the storage service (incurs simulated overheads)

Parameters:

  • location – a location

  • num_bytes – a number of bytes to read

void readFile(S4U_CommPort *answer_commport, const std::shared_ptr<FileLocation> &location, sg_size_t num_bytes, bool wait_for_answer)

Read a file from the storage service.

Parameters:

  • answer_commport – the commport on which to expect the answer

  • location – the location

  • num_bytes – the number of bytes to read

  • wait_for_answer – whether to wait for the answer

virtual void removeDirectory(const std::string &path) override

Remove a directory and all files at the storage service (in zero simulated time)

Parameters:

path – a path

virtual void removeFile(const std::shared_ptr<FileLocation> &location) override

Remove a file at the storage service (in zero simulated time)

Parameters:

location – a location

inline virtual bool reserveSpace(std::shared_ptr<FileLocation> &location) override

Reserve space at the storage service (basically, add bytes to a hidden un-evictable file in zero time)

Parameters:

location – a location

Returns:

true if success, false otherwise

inline virtual void unreserveSpace(std::shared_ptr<FileLocation> &location) override

Unreserve space at the storage service (basically, remove bytes to a hidden un-evictable file in zero time)

Parameters:

location – a location

inline void writeFile(const std::shared_ptr<DataFile> &file)

Write a file at the storage service (incurs simulated overheads)

Parameters:

file – a file

inline void writeFile(const std::shared_ptr<DataFile> &file, const std::string &path)

Write a file at the storage service (incurs simulated overheads)

Parameters:

  • file – a file

  • path – a path

inline void writeFile(const std::shared_ptr<FileLocation> &location)

Write a file at the storage service (incurs simulated overheads)

Parameters:

location – a location

void writeFile(S4U_CommPort *answer_commport, const std::shared_ptr<FileLocation> &location, sg_size_t num_bytes_to_write, bool wait_for_answer)

Synchronously write a file to the storage service.

Parameters:

  • answer_commport – the commport on which to expect the answer

  • location – the location

  • num_bytes_to_write – the number of bytes to write to the file.

  • wait_for_answer – whether to wait for the answer

Public Static Functions

static SimpleStorageService *createSimpleStorageService(const std::string &hostname, const std::set<std::string> &mount_points, WRENCH_PROPERTY_COLLECTION_TYPE property_list = {}, const WRENCH_MESSAGE_PAYLOAD_COLLECTION_TYPE &messagepayload_list = {})

Factory method to create SimpleStorageService instances.

Parameters:

  • hostname – the name of the host on which to start the service

  • mount_points – the set of mount points

  • property_list – a property list ({} means “use all defaults”)

  • messagepayload_list – a message payload list ({} means “use all defaults”)

Returns:

a pointer to a simple storage service