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Because the communication problem crossed multiple team boundaries, a cross-functional team was created to address the issues, with representatives from all interested parties -- finance, storage operations, business management, capacity planning and storage engineering. The team reached a consensus that a systematic, repeatable and traceable method to track and forecast network-attached storage (NAS), SAN and backup infrastructure was needed. This method would have to facilitate understanding for all storage capacity stakeholders by providing the following capabilities:
- Infrastructure ordering personnel would be able to place customer orders without being required to be "storage Gurus."
- Storage administrators would be able to use customer orders to create forecasts against the key physical and virtual storage components, while meeting customer requirements and business constraints, in a repeatable fashion.
- Business managers would be able to track customer demand to proposed infrastructure projects.
- Storage managers would be able to justify non-customer infrastructure capacity increase requirements, such as temporary storage needed for a data migration or to accommodate the organic growth of a specific storage subsystem.
- Storage engineers would need to verify that storage infrastructure is deployed consistently and adheres to engineering standards.
The storage management solution
The cross-functional team implemented a storage ledger, or storage "checkbook" with multiple "currencies" related to key storage consumables. For an ordinary checkbook, money is the only consumable, but a storage ledger checkbook has many consumables. The team decided to create three separate ledgers to track all consumables related to three major storage activities: NAS, SAN and backup. A single ledger was considered as it would have reduced the work for the groups that order storage, but the ledger would have been more complicated and considerably larger.
How a storage ledger works
Each ledger consists of two types of spreadsheets: a main ledger sheet and the component aggregation sheet used to calculate the top line (beginning balance) for each storage consumable that needs to be tracked. The main ledger sheet is divided into two sections. The first includes ordering columns where customers of storage services can write post-dated storage capacity checks. The information entered in the ordering columns drives the entries placed in the second set of columns, the storage capacity columns. The storage capacity columns aren't visible to the customers writing checks. The storage capacity columns include information needed by data storage administrators to map requests to a set of storage consumables associated with the appropriate environment and technology.
Click here to see a larger view of Ford Motor Company's capacity ledger.
This was first published in January 2010