Published: 12 Oct 2007
A proliferation of files that consume large amounts of disk space, and the increasing pressure to archive records for compliance and ediscovery, means smart capacity management is more important than ever. Here are 10 ways to improve your storage capacity management.
- Set written storage and retention policies. Before deleting the MP3 files in everyone's home directory, put policies in place that leave some room for exceptions. (Deleting the CEO's recorded speeches, for example, won't make IT too popular.) Company policies should make it clear if keeping pornographic images or pirated music on corporate computers is grounds for termination. And once these policies are in place, enforce them.
- Remember, storage is cheap; re-creating intellectual property is very expensive. Capacity management isn't just about removing troublesome files, it's also about keeping legitimate data safe and accessible. When defining storage policies, err on the side of caution. Some user directories can be exempt from pruning but should be monitored anyway. You might want to give the marketing department permissions for video and audio, but you don't want their directory bogged down with unnecessary or unintentionally downloaded files.
- Invest in storage management tools. These tools can tell you who's using what storage; categorize usage by file type to spot content that should be deleted; automate the process of notifying users if they're using a lot of space; and automatically remove inappropriate content. If you use this last capability, first consider moving files to a holding directory before permanently deleting them.
- Use thin provisioning. Thin provisioning allows you to create a volume with 100GB of space, for example, that will consume only a few megabytes of storage initially; more space is allocated to the volume as needed. This means volumes can keep pace with expanding storage needs without overallocating space that can't be used elsewhere. Also, you won't have to buy right now what you think you might need in 24 months.
- Use tiered storage. Some storage management products let you designate multiple tiers of storage, generally based on performance and cost. This might include high-speed storage for IO-intensive data such as databases and server working files, nearline storage and offsite tape archives. The management system can automatically move files that aren't used regularly to lower storage tiers, and move them back to higher tiers if they're accessed again.
- Explore deduplication. Deduplication products look for duplicate copies of files or data blocks and store the unique data only once. Some will deduplicate data as it's moved into or removed from storage, while others can substitute duplicate data with placeholders that point to the original copy.
- Consider storage virtualization. Storage virtualization allows you to disconnect the disk space used by your server data from your physical disks. That means a volume that's presented on the network as server1directory1 may actually not be anywhere near server1 physically. Because virtualization lets you move data without impacting user access, you can consolidate data from a dozen physical servers to a single storage silo. Further, if you combine storage virtualization with thin provisioning you'll have an extremely flexible storage system.
- Don't limit mailbox sizes. Rather than setting hard limits on mailbox sizes that force users to save local .pst files that can't be backed up, use an archiving tool that moves old messages to secondary storage. These tools leave stubs in place of archived messages; when a user tries to open an archived message, it's automatically retrieved from the secondary storage. This keeps mail server storage at reasonable levels and ensures that all email is safely archived and searchable.
- Don't limit home directories. While it may be tempting to set hard limits on the sizes of users' home directories, this encourages them to move the data elsewhere, usually to their local PC, where it may not get backed up, can't be indexed and searched, and generally can't be managed.
- You can effectively manage capacity without denying services. Capacity management policies are often perceived as a way of ensuring that users or apps don't take more storage than their "share." But this can lead to a lot of time spent trying to comply with inflexible or confusing rules. Instead, think about managing capacity rather than controlling it; this will save space, limit liability, ensure availability and give users what they need to get their jobs done.