This page comments on the hard drive storage requirements for an MD Link installation. There are two parts of the installation to consider: MD Link's application folder and MD Link's data folder. (More information is here.) The drive usage of the application folder doesn't change after installation. As of MD Link version 6.8.0, it uses 954 megs. The drive usage of the data folder changes dramatically over time, starting immediately after installation. The rest of this page is about the data folder, not the application folder.
Most of the drive space used by the data folder is used by the persistence database folder within it. MD Link's persistence database may consume a lot of disk space when running the service for months or years. If one disables the solution-level auto-purge options, or sets them to very high values, or is running MD Link on a machine with limited disk space, then one will need to pay attention to this. What follows is a rough disk space guideline for the MD Link service.
For a typical solution handling medium-sized HL7 messages, the amount of disk space required under the data folder, to hold both message data and log messages, can be approximated by the following formula:
<Number of messages per meg of disk space>
= 250 divided by <the number of components in the solution>
Equivalently:
<Number of megs per day>
= <number of components in solution> times <number of messages per day> divided by 250
For example, if you have a solution that contains 3 components, and it is processing 100000 messages per day, then that will use roughly 3*100000/250 = 1200 megs per day. If you have the auto-purge settings set to 14 days, this solution will use 1200*14 = 16800 megs = 16.8 gigs of disk space.
The number of components (i.e. events + resources + tasks) is typically the major determining factor. The size of those messages, incidentally, does not have a significant impact - at least not for messages in the typical size range for MD Link - 2000 characters or less.
Furthermore, if you have large input queues building up, then the additional amount of disk space require by each input queue is approximately 1 meg for every 5000 input queue elements. This is much smaller because internally, the queue structures don’t contain the message payloads – they only contain references to the message payloads, which are stored in the part of the database addressed by the message data guideline, above.