by Elizabeth Ferrarini
Which employees use the most disk space, and why? What's the best way to partition disk space on a storage area network so that all multi-platform servers have access to it? What proof do you have that all your files are being backed up?
Some IT professionals won't have any trouble answering these questions because they use storage resource management (SRM) software to identify and prevent capacity or performance problems and plan for future storage growth. John Webster, a storage analyst with the Illuminata consulting firm in Nashua, NH, says, "Some systems administrators don't have a clue about how much storage they have or how it's being used until it's too late. SRM tools can provide all the answers and can ward off an outage."
SRM software vendors include Astrum Software, BMC Software, Computer Associates, EMC, HighGround, NTP Software, Veritas Software, and W. Quinn Associates.
SRM tools monitor, alert, and report on the health, configuration, availability, performance, and usage of networked storage resources. Unlike specific storage management tasks such as backup, SRM tools provide a central view of either physical storage resources (e.g., RAID systems, tape libraries, and switches) or logical storage objects (e.g., volumes, files, and database tables).
SRM tools fall into 10 distinct application disciplines: asset management, capacity management, chargeback, configuration management, data/ device/media migration, event management and alerts, performance management, policy management, quota/ space management, and removable media management. Most SRM tools combine several disciplines.
- Asset management tracks and keeps records of all physical storage hardware on network.
- Capacity management compiles real-time and historical data on storage resources such as unused space on specific volumes.
- Chargeback acts as an accountant for billing end-user departments for used storage capacity and other storage-related network resources.
- Configuration management determines how to best arrange current physical network storage such as disk subsystems and switches.
- Data/device/media migration enables large amounts of data to be moved from one system to another.
- Event management alerts system administrators to errors on storage devices such as hard-drive failures and records all events.
- Performance management provides an ongoing view of application, server, and subsystem performance such as excessive I/O from application servers.
- Policy management specifies rules or policies for managing hardware, files, users, schedules, and media.
- Quota/space management optimizes disk usage by assigning specific space allotments to users and reclaiming wasted space.
- Removable media management maintains a history of on-site and off-site tape, optical, and other media.
How SRM works
Most SRM tools offer two levels of functionality: monitoring and alerting (on-screen, e-mail, or paging) to provide for day-to-day maintenance of storage resources, and reporting and trending to provide for long-term maintenance and planning.
SRM software usually consists of a service that runs the application managed from a central console, a mechanism for scanning monitored resources, a database that stores collected data from monitored resources, and a report generator that can output to various formats such as HTML or Excel.
By supporting SNMP, SRM software can also be administered from network- management frameworks.
SRM tools that combine the application disciplines of quota/space management, capacity management, and performance management enable IT professionals to know what their disk-space consumption looks like and how to distribute it evenly as a shared resource.
Key functions for maintaining day-to-day space consumption and storage performance include
- Determining disk-space usage as a result of thresholds on a user's home directory or a department's folders, getting alerts when thresholds are about to be reached or exceeded, and responding to alerts;
- Running HTML usage reports that let employees easily clean out their quota space;
- Setting filters to keep non-business file types such as .mp3s and .vbs files from being saved on the network;
- Setting thresholds on I/O performance, getting alerts when thresholds are about to be reached or exceeded, and correcting any problems; and
- Identifying specific storage resources such as disk drives that are most likely to fail or run out of space and taking steps to prevent failures.
Key planning functions include
Locating the areas of stale and unused space, and setting up policies for re-allocating that space through file migration to less permanent storage;
- Tracking the growth of files and assessing the implications on file migration, backup, and archiving operations; and
- Tracking file usage to make decisions about loading balancing, and identifying growth trends such as which applications are growing the fastest.
Future SRM tools
Some vendors plan to enhance their SRM tools with more functionality, particularly in the areas of data/device media migration and policy management. Illuminata's Webster says future SRM tools will need to manage multi-platform pools of storage with views from the storage facility, the attached servers, operating systems, file system, and the storage internetworking components. This type of SRM software could provide a panoramic picture of all storage resources.
Elizabeth Ferrarini is a freelance writer and consultant based in Boston.