System and method for data migration

A method of managing a plurality of data storage media, each of said media being designatable as being in a writeable state or a non-writeable state, said method comprising:

• designating a quantity of said plurality of media as being in the writeable state, said quantity being equal to a concurrency value;
• determining that none of the media designated in the writeable state has sufficient space to store specified data;
• designating an additional one of said plurality of media as being in the writeable state whereby the aggregate number of media in the writeable state exceeds said concurrency value;
• and
• writing said specified data to the additional medium,
• wherein said specified data comprises a plurality of data objects, and wherein said method further comprises persisting in a memory the locations on which each of said data objects is store, wherein each of said data objects is a file stored in a file system, and wherein said persisting act comprises:
• setting a reparse point in said file system for each of the files;
• and
• storing the location of each migrated file in the reparse point corresponding to the migrated file.

A method of using a plurality of media for a data migration system, each of said media being designatable as being in a writeable state or a non-writeable state, said method comprising:

• receiving a request to migrate a quantity of data;
• identifying, from among said plurality of media, a set of media that are in the writeable state and that have sufficient space to store said quantity of data;
• determining that each of the media in said set is in use for the reading or writing of data;
• determining that the number of said plurality of media in the writeable state is greater than or equal to a first number;
• waiting for a medium from said set to become available;
• and
• writing said data to the available medium,
• wherein said data comprises a plurality of data objects, and wherein said method further comprises persisting in a memory the locations to which each of said data objects has been migrated, wherein each of said data objects is a file stored in a file system, and wherein said persisting act comprises:
• setting a reparse point in said file system for each of the migrated files;
• and
• storing the location of each migrated file in the reparse point corresponding to the migrated file.

A method of using a plurality of media for a data migration system, each of said media being designatable as being in a writeable state or a non-writeable state, said method comprising:

• receiving a request to migrate a quantity of data;
• identifying from among said plurality of media, a set of media that are in the writeable state and that have sufficient space to store said quantity of data;
• determining that each of the media in said set is in use for the reading or writing of data;
• determining that the number of said plurality of media in the writeable state is greater than or equal to a first number;
• waiting for a medium from said set to become available;
• and
• writing said data to the available medium,
• wherein said data migration system includes a device having one or more drives which read and write said plurality of media, a library for the storage of media, and a robotic mechanism which mounts media stored in said library on said drives, said method further comprising:
• determining that none of the media located in said library is in the writeable state.

A method of using a plurality of double-sided media for a data migration system, each side of said media being designatable as being in a writeable state or a non-writeable state, said method comprising:

• receiving a request to migrate a quantity of data;
• identifying, from among said plurality of media, a first set of media having a side in the writeable state and whose side in the writeable state has sufficient space to store said quantity of data;
• determining that each of said media in said first set is in use for the reading or writing of data;
• identifying a first one of said plurality of media which is not in use for the reading or writing of data, and which has a first side that is in the non-writeable state and a second side whose state is not designated;
• designating said second side of said first medium as being in the writeable state;
• and
• writing said data to said second side of said first medium,
• wherein said data migration system includes a device having one or more drives which read and write said plurality of media, a library for the storage of media, and a robotic mechanism which mounts media stored in said library on said drives, said method further comprising;
• identifying, from among said plurality of media, a second set of media having a side in the writeable state and whose side in the writeable state has sufficient space to store said quantity of data, said second set being different from said first set;
• and
• determining that each of said media in said second set is not located in said device.

A method of storing a quantity of data on one of a plurality of media, each of said media being designatable as being in a writeable state or a non-writeable state, said method comprising:

• determining that the number of said media in a writeable state is greater than or equal to a first number;
• determining whether any of said media in a writeable state have sufficient space to store said data;
• if any of said media in a writeable state have sufficient space to store said data, writing said data to a first of said media in the writeable state;
• and
• if none of said media in said writeable state have sufficient space to store said data;
• identifying a second medium, said second medium not being designated as being in either the writeable state or the non-writeable state;
• designating said second medium as being in the writeable state;
• and
• writing said data to said second medium wherein said media are mountable on one or more drives, said drives being associated with a device, said device having a library which stores media and a robotic mechanism which mounts media stored in said library on said drives, wherein said method further comprises:
• determining that said first medium is presently in use for the reading and writing of data;
• waiting for said first medium to become available prior to writing said data to said first medium;
• and
• determining that said first medium is not stored in said library;
• and wherein said waiting act comprises;
• prompting a user to insert said first medium in said device.

A system for storing data on media comprising:

• a media management module which communicates with a database that stores attributes of a plurality of media, and which selects media for writing in accordance with the attributes stored in said database, said media management module including logic which selects said media based on a concurrency value;
• a migration module which communicates with a storage device, said storage device including a plurality of drives which write data to said media, said migration module receiving an indication of a selected medium from said media management module and writing data to the selected medium using said storage device;
• and
• a persistence module which receives from said migration module the location at which said data is stored on said media, and which stores the location of said data in a memory location.
• wherein said data object storage system comprises a settable reparse point for each data object stored in said data object storage system, each of said reparse points comprising a reparse data location, wherein said memory location comprises at least one of the reparse data locations.