You can use storage resource management software to plan for, and to manage, SANs.
By Elizabeth M. Ferrarini
An emerging set of storage management tools-referred to as storage resource management (SRM) software-provides the intelligence you need to plan for a storage area network (SAN) and to manage it. The potential benefits provided by SRM tools have led to a fast-growing market. For example, Dataquest's "Storage Management Software Market Expands Beyond Backup/HSM" report forecasts SRM to be the fastest growing segment of the overall storage management software market, which is expected to hit $4.8 billion in 2002. In 1997, SRM accounted for $210 million in revenues. Dataquest predicts that, by 2002, the market for SRM software will skyrocket to $1.2 billion.
Meanwhile, the backup software market is expected to grow from $1.7 billion in 1997 to $2.4 billion in 2002. "Core applications," such as volume management, are expected to grow from $500 million in 1997 to $1.2 billion in 2002.
Planning for SAns
As you move closer to a SAN pilot, you must first decide which data and applications belong on the SAN and which should remain on servers with direct-attached SCSI RAID or JBOD devices. Michael Peterson, president of Strategic Research, targets storage-intensive and mission-critical applications as the most obvious SAN candidates. "Applications such as e-mail and enterprise resource planning can benefit most from a SAN. It will give these applications advantages in performance, availability, and data protection," says Peterson.
To configure a SAN, you must decide how best to partition storage arrays (e.g., which parts of the disks will be assigned to which applications). The needs of your end users should determine how you partition the arrays.
Look at past and current storage consumption and usage patterns and ask questions such as the following:
- Which of your servers and workstations will have access to which partitions?
- What kinds of user activity can be expected?
- How much capacity should each partition have?
- Which partitions should be shared by more than one server for failover?
- What is the ratio of application files to data files?
SRM tools can provide the data you need to answer the questions for configuring a SAN. SRM software provides a consolidated view of all your current storage resources. Specifically, this emerging class of storage management tools provides detailed monitoring, alerting, reporting, and trending of storage resources.
These resources could include RAID arrays, individual disk drives, partitions, file systems, and files. "SRM is to logical and physical storage resources as network management is to routers, hubs, and packets," says Peterson.
Features to look for in SRM tools include: *
- Automated polling intervals
- Partition space thresholds
- Asset and configuration management
- Alarm/alert generation
- User consumption monitoring
- Backup sizing and planning
- Load monitoring and leveling
- Performance metering and management
Network management frameworks such as CA Unicenter, HP OpenView, and Tivoli TME provide some SRM features, such as user-consumption monitoring. SRM tools, however, provide a full network view of storage resources. And many SRM tools can be integrated with network management frameworks.
Although there is no firm definition for SRM, according to a variety of analysts SRM vendors (and products) include Astrum Software (StorCast SRM), BMC (Resolve), EMC (Control Center), Hewlett-Packard (SAN Manager), HighGround (Storage Resource Manager), Legato (GEMS Director), Softworks (CenterStage), Sterling Software (SAMS:Vantage), and Veritas (Storage Manager and related products). Vendors that OEM or resell HighGround's software include Bull, Compaq, CommVault, and IBM.
HighGround's Storage Resource Manager provides predictive reporting and event management for storage resources.
Most SRM packages automatically scan everything from disks to share points, and make this data available as realtime alerts, dynamic reports, and historical trends.
You can use these reports and trends to classify and to measure your current stor- age as a SAN candidate. You can go one step further and use SRM information from the SAN once it is deployed.
Deciding what storage to move to a SAN and what storage to leave on servers with attached storage resources involves classifying all of your network storage. Without automated SRM tools, this is a daunting task.
Some SRM tools provide the file size information needed for comparing and contrasting your current server storage and locating servers with lots of large files. You may even want to drill down and get the details on every one of the files. This information will help determine whether this storage could benefit from being migrated to a SAN.
SRM tools with filtering capabilities help you audit network storage for SAN planning and migration. For example, setting user-defined filters can yield a report with the largest files for an entire NT-based network or for specific disk partitions or servers. By using more filters, you can then locate files by type. You can even use the filters to get reports by file size, file creation, and file modification.
Using SRM to set up a SAN
How do you partition disk space on a SAN so it can be connected to and accessed by various servers and workstations? You need to understand storage use patterns, user behavior, and partition, directory, and file statistics. SRM can provide the historical trends of end-user space consumption and file access, modification, creation, and size statistics. With this information, you can partition disk space for best results.
Capacity consumption rates and historical trends (filtered by administrators) can help you determine peak access time as well as identify high-demand users. Likewise, SAN partition capacity requirements can be easily determined by looking at reports for the amount of directory space. Again, filtering by file size can help analyze the ratio of application files to data files for SAN and RAID tuning.
Using SRM to manage a SAN
Managing a SAN can threaten to complicate, rather than simplify, your job. A SAN may handle triple the amount of storage previously available on server-attached storage. This data may reside in one data center or on dozens of storage devices distributed throughout the organization.
For ongoing SAN management, you can use SRM tools to poll and monitor logical and physical storage resources. SRM tools that support SNMP traps ensure that SAN alerts get issued through network management frameworks such as CA Unicenter, HP OpenView, and Tivoli TME. Discovering SAN assets, such as Fibre Channel disks, can help you define alerts and thresholds for file-server partitions. SRM reports for backup sizing, as well as historical trends, can help ensure data availability.
Unfortunately, most companies do not have corporate storage policies. However, Farid Neema, president of Peripheral Concepts, a storage consulting firm in Santa Barbara, CA, says this will change. "Companies now realize that employees abuse storage space if no one is paying attention to it," says Neema. "Using SRM tools, systems administrators can set space limits, unobtrusively monitor the rates at which that space is being used, determine who is using it and who is abusing it, and determine what actions to take."
Office equipment supplier Staples has a storage usage policy in place. The company's corporate IT department, in Framingham, MA, uses HighGround's Storage Resource Manager software to track storage usage statistics across 75 servers. Helen Flanagan, a Windows NT systems administrator at Staples, uses the SRM software to track disk space by attributes such as servers, directories, partitions, and users. She gets alerts from Storage Resource Manager when individuals exceed their space allotment or when certain types of files start piling up.
Upjohn Pharmacia, in Kalamazoo, MI, also uses HighGround's Storage Resource Manager software. Upjohn uses the SRM software to track storage space on 29 servers used by about 5,000 employees. Linda Echevarria, a systems engineer in a group that tracks storage usage, says that if she sees, say, an executable program in someone's server directory, she'll send them an e-mail message asking them to delete it.
Likewise, if she sees an application program she'll ask the employee to store it on a specific application server. Echevarria also uses SRM software on a daily basis to see if disk space on the servers has dropped below pre-defined levels.
Elizabeth Ferrarini is a Boston-based freelance writer and author of two computer books. She can be reached at firstname.lastname@example.org.
Are you prepared for NT growth?
Many companies may not be prepared to handle the growth of disk space usage on their Windows NT network servers. At least, this is one conclusion that can be drawn from a survey of 500 organizations, commissioned by Astrum Software.
Of the 500 organizations responding to the survey, 53% said they had an outage or a disk crash because an NT server was about to run out of disk space. This figure was 59% for organizations with revenues between $100 million and $200 million.
The survey found that only 28% of all the organizations used some sort of Windows utilities to monitor the amount of disk space on their NT servers, and only 9% used a utility to monitor disk space on Windows desktops.
Microsoft Word Files, PowerPoint slides, and e-mail attachments are the types of files most likely to clog the NT servers, according to the respondents. The total percentage for a list of 13 files types includes the following: Word files topped the list at 40%, followed by PowerPoint at 34%, e-mail attachments at 39%, and graphics files at 32%.
The findings of the survey dovetail with findings from a survey done by Strategic Research, a Santa Barbara, CA, market research firm specializing in storage.
Strategic Research found that applications, such as Web downloads, e-mail attachments, and e-commerce transactions, have caused on average a doubling in disk storage on servers and desktops in both large organizations and home offices.
The firm also found that the average amount of storage space managed by a system administrator has jumped more than 70% in two years. This space will nearly triple during the next four years.