Abstract: Embodiments relate to adaptive memory apportioning. An aspect includes, statistics captured for a plurality of elements of a partitioned linear address space. Each addressable location is an element in the address space. Subspaces of the partitioned linear address space are rated based on captured statistics of at least one element. The subspaces are differentiated, based on the frequency of access, as being of lesser and greater significance. The boundaries that separate the subspaces are altered so as to effect coarser granularity in the subspaces determined to have the lesser significance and finer granularity in the subspaces determined to have the greater significance.

Abstract: A computer program product, system, and method for managing metadata for caching devices during shutdown and restart procedures. Fragment metadata for each fragment of data from the storage server stored in the cache device is generated. The fragment metadata is written to at least one chunk of storage in the cache device in a metadata directory in the cache device. For each of the at least one chunk in the cache device to which the fragment metadata is written, chunk metadata is generated for the chunk and writing the generated chunk metadata to the metadata directory in the cache device. Header metadata having information on access of the storage server is written to the metadata directory in the cache device. The written header metadata, chunk metadata, and fragment metadata are used to validate the metadata directory and the fragment data in the cache device during a restart operation.

Abstract: Embodiments relate to non-disruptive modification of a device mapper stack. Aspects include receiving the device mapper stack comprising a first device mapper layer having an active mapping table and creating a second device mapper layer having a copy of the active mapping table from the first device mapper layer. Aspects further include creating an inactive mapping table having a desired mapping logic in the first device mapper layer and suspending and resuming an operation of the first device mapper layer. Suspending and resuming causes the active mapping table of the first device mapper layer to be replaced with the inactive mapping table of the first device mapper layer.

Abstract: A computer program product, system, and method for managing metadata for caching devices during shutdown and restart procedures. Fragment metadata for each fragment of data from the storage server stored in the cache device is generated. The fragment metadata is written to at least one chunk of storage in the cache device in a metadata directory in the cache device. For each of the at least one chunk in the cache device to which the fragment metadata is written, chunk metadata is generated for the chunk and writing the generated chunk metadata to the metadata directory in the cache device. Header metadata having information on access of the storage server is written to the metadata directory in the cache device. The written header metadata, chunk metadata, and fragment metadata are used to validate the metadata directory and the fragment data in the cache device during a restart operation.

Abstract: Embodiments relate to adaptive memory apportioning. An aspect includes, statistics captured for a plurality of elements of a partitioned linear address space. Each addressable location is an element in the address space. Subspaces of the partitioned linear address space are rated based on captured statistics of at least one element. The subspaces are differentiated, based on the frequency of access, as being of lesser and greater significance. The boundaries that separate the subspaces are altered so as to effect coarser granularity in the subspaces determined to have the lesser significance and finer granularity in the subspaces determined to have the greater significance.

Abstract: A computer program product, system, and method for managing metadata for caching devices during shutdown and restart procedures. Fragment metadata for each fragment of data from the storage server stored in the cache device is generated. The fragment metadata is written to at least one chunk of storage in the cache device in a metadata directory in the cache device. For each of the at least one chunk in the cache device to which the fragment metadata is written, chunk metadata is generated for the chunk and writing the generated chunk metadata to the metadata directory in the cache device. Header metadata having information on access of the storage server is written to the metadata directory in the cache device. The written header metadata, chunk metadata, and fragment metadata are used to validate the metadata directory and the fragment data in the cache device during a restart operation.

Abstract: Embodiments relate to non-disruptive modification of a device mapper stack. Aspects include receiving the device mapper stack comprising a first device mapper layer having an active mapping table and creating a second device mapper layer having a copy of the active mapping table from the first device mapper layer. Aspects further include creating an inactive mapping table having a desired mapping logic in the first device mapper layer and suspending and resuming an operation of the first device mapper layer. Suspending and resuming causes the active mapping table of the first device mapper layer to be replaced with the inactive mapping table of the first device mapper layer.

Abstract: Input/output (I/O) activity in the multiple tier storage system is monitored to collect statistical information. The statistical information is recurrently transformed into an exponential moving average (EMA) of the I/O activity having a predefined smoothing factor. Data portions in the multiple tier storage system are sorted into buckets of varying temperatures corresponding to the EMA. At least one data migration plan is recurrently generated for matching the sorted data portions to at least one of an available plurality of storage device classes. One data portion sorted into a higher temperature bucket is matched with a higher performance storage device class of the available plurality of storage device classes than another data portion sorted into a lower temperature bucket.

Abstract: Input/output (I/O) activity in the multiple tier storage system is monitored to collect statistical information. The statistical information is recurrently transformed into an exponential moving average (EMA) of the I/O activity having a predefined smoothing factor. Data portions in the multiple tier storage system are sorted into buckets of varying temperatures corresponding to the EMA. At least one data migration plan is recurrently generated for matching the sorted data portions to at least one of an available plurality of storage device classes. One data portion sorted into a higher temperature bucket is matched with a higher performance storage device class of the available plurality of storage device classes than another data portion sorted into a lower temperature bucket.

Abstract: Input/output (I/O) activity in the multiple tier storage system is monitored to collect statistical information. The statistical information is recurrently transformed into an exponential moving average (EMA) of the I/O activity having a predefined smoothing factor. Data portions in the multiple tier storage system are sorted into buckets of varying temperatures corresponding to the EMA. At least one data migration plan is recurrently generated for matching the sorted data portions to at least one of an available plurality of storage device classes. One data portion sorted into a higher temperature bucket is matched with a higher performance storage device class of the available plurality of storage device classes than another data portion sorted into a lower temperature bucket.

Abstract: A method for matching storage application performance in a multiple tier storage system is disclosed. Input/output (I/O) activity in the multiple tier storage system is monitored to collect statistical information. The statistical information is recurrently transformed into an exponential moving average (EMA) of the I/O activity having a predefined smoothing factor. Data portions in the multiple tier storage system are sorted into buckets of varying temperatures corresponding to the EMA. At least one data migration plan is recurrently generated for matching the sorted data portions to at least one of an available plurality of storage device classes. One data portion sorted into a higher temperature bucket is matched with a higher performance storage device class of the available plurality of storage device classes than another data portion sorted into a lower temperature bucket.