This analysis is based on estimate of 300 vouchers per day, and a sample scan of one box of 191 archived voucher files. The scan resulted in a total of 1,947 images, and required 92.6 Mbytes to store. The files averaged 485 Kbytes in size and 10.2 images each. The scanning was done using a Canon CD-4070NW Document Imaging System.

The files were stored as PDF files with the naming convention of: <Statewide Document Number> (space) <Voucher Number>_00001.PDF.

Use of this naming convention allows for a simple windows search to find a given file based on “begins with”, “ends with” or “contains” a portion of the file name. With a standard filename such as this, the filename describes the contents, and allows for simple inclusion into a database by referencing the document’s titles.

Finance and Accounting desires to have a system capable of storing seven year’s worth of voucher images. The approximate storage space is calculated as follows:

300 vouchers per day for 22 workdays per month and 12 months = 79,200 vouchers per year

79,200 vouchers per year times 10.2 images per voucher = 950,400 images per year

79,200 vouchers per year times 485 Kbytes = 38.4 GBytes per year.

38.4 times 7 years = 268.8 GBytes of storage space needed (with no growth).

We recommend that you have a backup strategy. Many people set up a server with adequate storage on a data drive, then use disk mirroring (RAID 1) to minimize the possibility of losing your working files. That would require a single system with two data drives of at least 300 GBytes each, configured to mirror the primary data drive to a secondary drive. You should also be able to backup your shared folders of data to an IT server, CDs, DVDs or tape backup over the network for absolute long term security.

Lastly, you should factor in your expected annual growth. These numbers will give you approximately 12% more space than a flat growth annual number, but if you have 10% growth per year you will need each of the disks to be at least 400 GBytes by the end of the 7 years.