Enforcing end-user storage quotas is getting tougher as free Web email accounts, such as Google's Gmail, give each user up to 2 gigabytes
Knology Inc., a managed service provider in West Point, Ga., limits its customers to 25 MB each, but that may have to change. "Google and Yahoo! may be forcing our hand," says Bradley Frye, senior manager of data network operations.
"This issue [of limiting end-user storage] has been around for 25 years," says Mike Karp, senior analyst at Enterprise Management Associates, a Boulder, Colo., research firm. "There's only so much storage at any given time, and IT managers are forced to enforce sometimes hidebound rules."
Like arguments with teenagers over curfews, conflicts over end-user disk quotas may be symptomatic of a more serious underlying problem. "The real problem is the amount of data on corporate storage that shouldn't be there," says Karp. "Some managers tell me that over half the data they store has no corporate value."
Limiting the amount of storage available to end users opens a Pandora's box of underlying issues: the cost difference between raw storage capacity and deploying and managing storage; classifying data in terms of corporate value and importance; and whether valuable corporate data is being inappropriately stored in personal storage folders. It also brings up the question of whether the organization should back up data stored in personal folders.
"These aren't easy issues," says Richard Villars, IDC's vice president, storage systems research. "The whole topic of disk quotas is really a behavioral discussion, not a technical discussion." Technically, disk quotas are simple to set up and manage.
"Disk is cheap," says Villars. But if you buy enough of them, cheap disks add up -- especially when you factor in the time, effort and cost of the tools to manage end-user quotas. "From a storage provisioning standpoint, especially without virtualization, continually adding storage is onerous," says Villars. That's one of the main reasons why most companies limit end-user storage rather than continually add disk capacity.
"I have to manage user capacity because I can't keep buying more disk every month," says Raymond Acuna, IT manager and MIS administrator for the Division of Disease Control at the Florida Department of Health. Acuna has 300 users in his department. Clerical people get 1 GB of personal storage, regular staff receive 4 GB and power users can get more as necessary.
Timothy Wetzel, system security analyst, infrastructure systems at Dickinson College in Carlisle, Pa., says the college uses RAID-0 and RAID-1 "so our disk costs are doubly expensive." The school allocates 200 MB to each of its 2,500 students, and 500 MB to each of its 1,200 faculty members and staff.
Letting users have all the storage they want also drives up the cost of backups. Christian Raymond, systems administrator at Ex-Centris, a movie theater and cultural events producer in Montreal, limits his 500 users to 300 MB of personal storage and 5 GB for corporate folders. Meanwhile, The Golf Channel doesn't back up users' personal storage space, but it does make snapshot copies, which it keeps for a couple of months, reports the firm's Formet. If a user inadvertently deletes or corrupts a file, Formet will recover it from the snapshot.
If you figure in the cost of backing up data or otherwise protecting it, the decision to limit storage increasingly looks like the right choice. "Imagine finding that you can't complete your backup within the overnight window because you're backing up personal data that has no value to the company," says Karp. In that case, the disk storage given over to users suddenly looks quite expensive.
Storage management discipline
Many organizations see end-user storage quotas not so much as a way to save money but to impose better storage management discipline and best practices. "Storage quotas help us keep tabs on what students need," says Robert Lowe, network manager at Lawrence University, Appleton, WI. "It gives us a monitoring mechanism [to forecast demand]."
"We restrict users to a small amount of storage for personal data, 50 MB. We want to enforce the discipline of centralized storage for all corporate work," says Gordon Butler, chief information technology officer at the Canadian Museum of Civilization, Gatineau, Quebec. Centralized data can be more easily protected, backed up and shared. All information related to a project can be organized in a logical place. Otherwise, "we get an awful duplication of data," says Butler, because users store data that should be centralized and shared in their personal folders.
Some managers resist what they consider pandering to end-user storage demands. "It's a ludicrous attitude of IT to give users more storage whenever they ask for it. Users are addicted to storage," says Colin Clark, business control executive at Somerfield Stores Ltd., Bristol, U.K. The real issue, as Clark sees it, is the ability to find information when it's needed. Giving users more storage doesn't make it easier for them to find data -- it makes it worse.
Quota management tools
Where Microsoft Windows is predominant, organizations can use Windows Server to enforce disk quotas. "If the environment is limited, it's smart to just do it in Windows," says IDC's Villars. For larger, more complicated environments or where compliance and governance issues are involved, IT will need more sophisticated tools.
Almost all NAS vendors and most storage array vendors offer disk quota management tools, typically included at no extra charge, reports Villars. Storage resource management (SRM) tools from Computer Associates (CA) International Inc., IBM Corp. and Symantec Corp., along with smaller players like Tools4ever Inc., also provide disk quota management of varying capabilities.
"We did not like Microsoft Disk Quota because it eats up server processing," says Acuna at the Florida Department of Health. After looking at the offerings from Microsoft Corp., Tivoli, Tools4ever and custom batch files, the organization settled on SpaceGuard SRM from Tools4ever. The custom batch files were easy to write, but an annoyance to maintain. Dickinson College also opted for SpaceGuard. "Windows is definitely cheaper, but SpaceGuard gives us more options," says the college's Wetzel. In particular, SpaceGuard lets the school send alerts to a wide range of targets, including email addresses, mobile phones, pagers, event logs and more.
Knology upgraded from a BlueArc Corp. Si8000 SiliconServer to the vendor's Titan array in part for the built-in quota management capabilities. The quota management feature lets Knology set and enforce quotas on email. When users hit the limit, the system rejects the email and fires off an alert to the customer, who can then delete email or upgrade to a higher service level.
The company, which runs an entirely open-source environment, looked at putting quota management into the application layer. "That would have taken more CPU cycles and we would have needed to upgrade our servers," says Knology's Frye. "It is easier, faster and cheaper to just do it at the storage array."
The Canadian Museum of Civilization opted for CA's quota management, part of CA's BrightStor suite. "We've been using BrightStor for three years," says the museum's Butler. He particularly likes the reporting and trending BrightStor allows. However, the organization also uses Windows tools in its Windows servers to set, monitor and enforce Windows share sizes.
It will be some time before most IT managers are as generous with end-user storage as Google or Yahoo!. Unfortunately, enforcing disk quotas is a fast way to engender resentment of IT. But no matter how low disk storage costs go, IT managers don't have much choice until the cost of provisioning, managing, backing up and protecting storage is free.
This article originally appeared in Storage magazine.
This was first published in November 2006