·
Usability
Aspects of the Drupal 6 administration
interface were seen to be confusing and intimidating to some, particularly for
new administrators. According to
Dries Buytaert, Drupal 7 addressed 90% of the problems identified by Usability
tests conducted at the Universities of Minnesota and Baltimore. To achieve this, Acquia(the company founded by the project lead of Drupal)
hired user
experience designer
Mark Boulton to work with the Drupal community to design an improved user
interface for Drupal's administration interface. The majority of his team's design work has
been implemented by the community in Drupal 7. The 2011 usability test results
from the University of Minnesota Office of Information Technology show that all
of the major usability problems identified in Drupal 6 are either vastly
improved or non-existent in Drupal 7. However, some new usability problems were
identified. Since the release of
Drupal 7 there are now various distributions and applications to enhance the
Back-end Usability of Drupal such as Drupal Gardens, Open Enterprise and Mitkom Builder.
·
Learning curve
Some users describe Drupal as being
difficult to master. Drupal's many contributed modules can have overlapping
functionality and have been reported as overwhelming to new users.
·
Backward compatibility (for software
development)
Drupal
does not commit to backward compatibility across major revisions. This means
that module and theme developers may have to rework their code to be
compatible. However, Drupal's policy is to not change how it uses one's data.
This means that data from previous versions will still be usable without
alteration in the new release. Drupal documents any incompatibilities, allowing
the user to make informed decisions about when and whether to upgrade.
·
Performance/scalability
In 2008, performance tests between
Drupal 6.1 and Joomla 1.5
demonstrated that Drupal's pages were delivered "significantly
faster" than those of Joomla. Despite
this, arguments over speed persist. Drupal
is likely to be slower than a special-purpose application for a given task. For
example, WordPress typically
outperforms Drupal as a single-user blogging tool. Drupal positions itself for
broader applications requirements that are outside the scope of more narrowly
focused applications. Drupal
offers caching to store various page elements, the use of
which resulted in a 508% improvement in one benchmark. When using Drupal's default Page Cache
mechanism, the cached pages are delivered only to anonymous users, so
contributed modules must be installed to allow caching content for logged in
users. Like performance, scalability (the ability to add servers to handle
growing numbers of visitors with consistent response) can become a concern on
large, interactive sites. MySQL's
query caching can help reduce the load on the database server caused by
Drupal's high query rate. Drupal
caches database schema metadata as well
as elements such as blocks, forms and menus. Drupal
7 increases performance in database queries and reduces PHP code usage.
· Integrability with hosting structures
Because of Drupal's demanding query
requirements, Drupal-based websites can quickly become very taxing to hosts
whose databases reside on a machine separate from their HTTP
server. While the issue can normally be addressed by implementing
aggressive caching as described above, such methods may be
unimplementable in cases where the host does not offer access to PHP
accelerators like XCache or APC. Drupal has plugins that facilitate similar caching without
requiring special PHP extensions.
·
The Drupal core search
There are contributed modules that will
greatly improve the search functionality on a Drupal website, but they are not
easily accessible due to a high learning curve and the difficulty users have in
general of finding the right module. One
of the faceted search options is Apache
Solr Search
Integration module, however, the module requires a dedicated server or virtual private server (VPS) to operate because Solr must run on a servlet container,
e.g. Tomcat, Jetty or
Resin. These requirements make it harder for a Drupal website to have a
functional search feature. In response, Acquia and other companies have created Apache Solr SaaS products.
