Scalability and Data Transfer

We rec­om­mend that all appli­ca­tion ser­vices be run in a pri­vate cloud envi­ron­ment. Many, if not most client users will con­nect to the pri­vate cloud using a wire­less inter­net con­nec­tion, so opti­miz­ing com­mu­ni­ca­tions is an impor­tant fac­tor in the scal­a­bil­i­ty of the application:

  • The amount of data trans­ferred – this is impor­tant because it is a good indi­ca­tor of the abil­i­ty of the entire sys­tem to scale to many users. In large imple­men­ta­tions like this, the net­work and the part of the sys­tem that sends the data over the net­work tend to become ear­ly bot­tle­necks in the over­all per­for­mance of the sys­tem. Trans­fer­ring less infor­ma­tion per inter­ac­tion will allow more to be done with the same resources. Addi­tion­al­ly, since most wire­less inter­net providers charge accord­ing to the amount of data trans­ferred, the less data sent for each inter­ac­tion, the low­er the cost of main­tain­ing the imple­men­ta­tion will be.
  • The time it takes to deliv­er the full screen to the client brows­er – this is tied to the “respon­sive­ness” of the appli­ca­tion in terms of time spent wait­ing by the users to see their search results, patient details, or to add new information.

In order to pro­vide a com­par­i­son between Verac­i­ty and many com­mon­ly accessed web sites, we per­formed sev­er­al tests and aver­aged their results:

The first test was a “time to load” com­par­i­son. For sites such as Google, Face­book and Twit­ter, we found their fastest load­ing pages (best case sce­nario) and used them for com­par­i­son. For Verac­i­ty pages, we took “dif­fi­cult to han­dle” (search­es that returned tens of thou­sands of records, very com­plete patient records, etc.) pages (worst case sce­nario) and used them. The times shown are in milliseconds.

The VSI Verac­i­ty search returned 9,500 rows of patient data in the time shown.

The sec­ond test shows the amount of data (in Kilo­bytes) sent from the serv­er to the brows­er for the sim­plest of pages (theirs) and the most dif­fi­cult pages (for Veracity):Scalability

So, how does this relate to Scalability?

Once the project has been installed and all users are trained, the data charges for the usage of the sys­tem will still be charged and either the coun­try, the munic­i­pal­i­ty or the local orga­ni­za­tion will need to pay for them. This is what has caused many projects in the past to fail – the equip­ment works well, the soft­ware meets local require­ments, but the data charges are unaffordable.

To pro­vide a sense of rel­a­tive costs, we test­ed the soft­ware we will use in these African imple­men­ta­tions against sev­er­al pop­u­lar web sites and mea­sured the cost of data that would be used to view each web­site 2 mil­lion times. We used a low-to-aver­age inter­net data usage rate in our comparisons.


Visual Software, Inc.