User manual HP STORAGEWORKS FILE SYSTEM EXTENDER (FSE)

[. . . ] HP StorageWorks File System Extender Software user guide Part number: T3648-96010 First edition: October 2006 Legal and notice information Copyright 2005, 2006 Hewlett-Packard Development Company, L. P. Consistent with FAR 12. 211 and 12. 212, Commercial Computer Software, Computer Software Documentation, and Technical Data for Commercial Items are licensed to the U. S. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. [. . . ] This happens when all migrated generations of the deleted files were considered obsolete (outdated) by the FSE media reorganization process and all medium volumes that stored these file generations were reorganized. CAUTION: When sensitive data is to be completely erased from the FSE implementation, you must ensure that they are first deleted from the HSM file system, and then reorganize its FSE media so that all migrated generations (and all additional copies if multiple copying is configured for the appropriate FSE partition) of the data are considered as obsolete. Additionally, if the migrated data reside on WORM-type media, these media must be removed from FSE and destroyed. Resource allocation FSE resources are physical and logical objects, controlled by the FSE implementation. For detailed information on configuring resources, see chapter "Configuring FSE" on page 37. Resource allocation concepts FSE resources can be grouped according to their characteristics, as follows: Physical resources: FSE libraries, each library includes FSE library slots FSE drives 140 Migration, release, recall, and deletion Logical resources: FSE media cartridges, each medium includes FSE medium volumes FSE media pools The figure below schematically shows the resources as they are represented in the FSE implementation Figure 28 Example of FSE resources Central FSE resource manager All resources of the FSE implementation are controlled by a central Resource Manager. Resource allocation is used each time an FSE job requires new resources. Typically, the Resource Manager locks the use of resources in the Resource Management Database for jobs that have requested allocation. Media selection by media location Allocation selects a medium according to its location. Possible locations of a medium are: Online: Medium is loaded into a drive. The Resource Manager always allocates media and drives that are in the same library first to avoid time-intensive load/unload operations. If there are still jobs in the queue and no online media are available, then nearline media are selected. Whenever possible, the current volume from an allocated medium is used. Otherwise, the volume with the highest use is selected to minimize the number of open volumes. Several allocation parameters There is only one Resource Manager for the whole FSE implementation, and therefore it is responsible for all FSE partitions. The parameters needed for resource allocation are different for the whole FSE implementation (system) and each partition; they are defined in the systems policies and in the partitions policies. HP StorageWorks File System Extender Software user guide 141 Note that resource allocation requests from different partitions can have different drive and priority policies, and that the same media pool cannot be assigned to several partitions. For more information on parameters for resource allocation, see "System allocation and job priority policy" on page 142 and "Partition allocation and job priority policy" on page 144. Job priorities When a new job is created, if all of the requested resources are available in the FSE implementation, Resource Manager allocates them and the job starts performing its task immediately. If some resources are not available, a resource request of the job is put into the resource allocation queue of the Resource Manager, and the job waits for availability of the resources. In case there are too many jobs already running for the corresponding FSE partition, the newly created job is not allowed to request resources yet, but is put into the state "pending" instead. Such pending job waits until the current job count for the FSE partition decreases below a threshold value, and can only request the resources from the Resource Manager afterwards. Pending jobs are processed in the "first come first served" order. The threshold job count is defined by the MaxNumDrives variable (specified in the FSE partition configuration file) as follows: ThresholdJobCount = 3/2 * MaxNumDrives IMPORTANT: The status pending is applicable only for jobs that can be run on a particular FSE partition: migration, recall, reorganization, and maintenance jobs. They are immediately started or queued in the resource allocation queue, no matter how many jobs are already running in the FSE implementation. When the resource request of a job is put into the resource allocation queue, the job is assigned an initial priority. When a new job is put into the queue, the priorities of all existing resource requests are recalculated; the priority of each job is then modified according to the elapsed time and the phase of the job. Each time a resource is freed, the queue is checked again to allocate the free resource. [. . . ] FSE tools are located in the directory /opt/fse/sbin/tools (on Linux platform) or in the directory %InstallPath%\bin (on Windows platform). An FSE medium to which further writing is disabled, but from which FSE is still able to read data. As soon as the first write error is detected while the Back End Agent is writing data to the medium, the medium is automatically marked as unreliable in the Resource Management Database. An FSE medium which has been disabled for both writing to and reading from. [. . . ]