Knozall FileWizard storage_management.htm
Storage Growth Creates Management Challenges
On-line storage capacity continues to grow at an exponential rate. For the past 40 years on-line storage capacity has increased at approximately 40 percent per year compound growth rate.
As more new applications come on line, the demand will continue to accelerate. New applications, such as storing of photographs, and other non-coded information, will keep storage needs on a rapid growth rate for the foreseeable future.
Over 250 IT executives at a conference (Storage Networking World Nov 2000) were asked about the size of enterprise storage now and what they estimated it would be in October of 2001. Their estimates indicated the median size of enterprise storage to be between 4 and 10 TB. This data concludes that the size of enterprise storage is rapidly moving to the greater than 26 terra byte size.
A survey conducted by Enterprise Strategy Group of 155 firms in 2004, shows the size of the on line storage in the enterprise is growing larger. The median size of enterprise storage is well above 10TB.
What is your biggest storage management problem?
In another survey, when asked the question, “What is your biggest storage management problem?” system administrators responded as shown in Figure 3. Managing disk space is the most often mentioned, followed by running out of disk space.
Figure 3 Biggest Storage Management Problems
Primary Goals of Storage Management
Critical data must be made available to the user on demand. It must be protected from loss and the data that must be kept for long periods of time needs to be archived. All of this in an environment that is getting more complex and has little tolerance for downtime.
The old way
As the cost per megabyte of disk storage plummeted, the great tempation was to respond to the needs for managing the data explosion which demanded 24x7 access was to add more hard drives, or another or larger server. This choice is short sighted, since it results in increasing manpower costs, increasing cost of ownership, and multiplies the management problems.
Although the notions of Hierarchical Storage Management (HSM) have been around for over 20 years, much of the implementation on networks has been expensive and complex. HSM allows each system administrator to set rules for migration to meet the needs of his system and users.
A typical HSM system will recognize a high water mark and a low water mark set by the system administrator. When the high water mark is reached, the system will automatically begin migrating files from the migration candidate list and will stop when the low water mark is reached. The migration candidate list has criteria such as size and date since last access, which determine which files can be migrated.
The hierarchy usually consists of the main disk storage, where you want files that are most often accessed. The next level, consists of a MO jukebox or some other random access storage device which is usually slower and cheaper than disk, will contain files that need to be on line, but are not accessed with the same frequency as other files. Finally, an archiving system and backup system that will serve the functions of record preservation and recovery is required for completing the needs for data preservation.
This system operates with no administrative intervention. The user wanting too access a migrated file simply clicks on the file, and the HSM system locates the file and recalls it to the users local disk drive. The operation of the HSM system is transparent to the user.