Data storage system with on-demand recovery of file import metadata during file system migration
First Claim
1. A computer-implemented method of processing a user I/O operation in a file system of a data storage system, the data storage system operating as a target data storage system performing a migration operation to migrate the file system to the target data storage system from a separate source data storage system, the method comprising the steps, performed by the target data storage system during a restart of the target data storage system occurring during the migration operation, of:
- assessing a migration state of a user file being the target of the user I/O operation, including (1) first determining whether a metadata file storing migration state data for the user file has an already recovered record for the user file accurately indicating the migration state of the file, the already recovered record having been recovered by a separate background recovery process performed during the restart, (2) when the metadata file has an already recovered record for the user file, then using the already recovered record to assess the migration state of the user file, and (3) when the metadata file does not have an already recovered record for the user file, then (a) initiating an on-demand recovery to obtain an on-demand recovered record for the user file, and (b) using the on-demand recovered record to assess the migration state of the user file; and
when the assessed migration state indicates that the file has not yet been migrated to the data storage system, then redirecting the user I/O operation to a separate source data storage system for processing the user I/O operation, and otherwise completing the user I/O operation by accessing the file as previously migrated to the data storage system from the source data storage system,wherein the on-demand recovery includes use of an on-demand recovered map being a content-addressed listing of inode numbers for files whose metadata records have been on-demand recovered during a post-restart recovery period.
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Accused Products
Abstract
A user I/O operation is processed in a file system of a target data storage system (DSS) performing a file system migration. The target DSS assesses a migration state of a user file of the user I/O operation, including (1) determining whether a metadata file storing migration state data for the user file has an already recovered record indicating the migration state of the file, (2) if so, then using the already recovered record to assess the migration state of the user file, and (3) otherwise (a) initiating an on-demand recovery to obtain an on-demand record for the user file, and (b) using the on-demand recovered record to assess the migration state. If the migration state indicates that the file has not yet been migrated, then the user I/O operation is redirected to a separate source DSS, and otherwise the user I/O operation is completed locally at the target DSS.
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Citations
18 Claims
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1. A computer-implemented method of processing a user I/O operation in a file system of a data storage system, the data storage system operating as a target data storage system performing a migration operation to migrate the file system to the target data storage system from a separate source data storage system, the method comprising the steps, performed by the target data storage system during a restart of the target data storage system occurring during the migration operation, of:
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assessing a migration state of a user file being the target of the user I/O operation, including (1) first determining whether a metadata file storing migration state data for the user file has an already recovered record for the user file accurately indicating the migration state of the file, the already recovered record having been recovered by a separate background recovery process performed during the restart, (2) when the metadata file has an already recovered record for the user file, then using the already recovered record to assess the migration state of the user file, and (3) when the metadata file does not have an already recovered record for the user file, then (a) initiating an on-demand recovery to obtain an on-demand recovered record for the user file, and (b) using the on-demand recovered record to assess the migration state of the user file; and when the assessed migration state indicates that the file has not yet been migrated to the data storage system, then redirecting the user I/O operation to a separate source data storage system for processing the user I/O operation, and otherwise completing the user I/O operation by accessing the file as previously migrated to the data storage system from the source data storage system, wherein the on-demand recovery includes use of an on-demand recovered map being a content-addressed listing of inode numbers for files whose metadata records have been on-demand recovered during a post-restart recovery period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A data storage system including secondary storage devices and processing and interface circuitry configured and operative to execute computer program instructions to realize a file system and to perform a method of processing a user I/O operation in the file system, and to operate the data storage system as a target data storage system performing a migration operation to migrate the file system to the target data storage system from a separate source data storage system during a restart of the target data storage system occurring during the migration operation, the method including:
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assessing a migration state of a user file being the target of the user I/O operation, including (1) first determining whether a metadata file storing migration state data for the user file has an already recovered record for the user file accurately indicating the migration state of the file, the already recovered record having been recovered by a separate background recovery process performed during the restart, (2) when the metadata file has an already recovered record for the user file, then using the already recovered record to assess the migration state of the user file, and (3) when the metadata file does not have an already recovered record for the user file, then (a) initiating an on-demand recovery to obtain an on-demand recovered record for the user file, and (b) using the on-demand recovered record to assess the migration state of the user file; and when the assessed migration state indicates that the file has not yet been migrated to the data storage system, then redirecting the user I/O operation to a separate source data storage system for processing the user I/O operation, and otherwise completing the user I/O operation by accessing the file as previously migrated to the data storage system from the source data storage system, wherein the on-demand recovery includes use of an on-demand recovered map being a content-addressed listing of inode numbers for files whose metadata records have been on-demand recovered during a post-restart recovery period. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification