When you get a Spectrum Scale solution from IBM you are certain of two things. 1) You will need a specialized storage admin who will be able to take all of its advantages and make available for your organization. It is an appliance that not so many storage admins would be comfortable working on. Invest properly on both hardware and human resources. 2) You will scale forever. We started with a couple of hundred of Terabytes and grew to dozens of Petabytes.
GFS is well suited for DEVOPS type environments where organizations prefer to invest in servers and DAS (direct attached storage) versus purchasing storage solutions/appliances. GFS allows organizations to scale their storage capacity at a fraction of the price using DAS HDDs versus committing to purchase licenses and hardware from a dedicated storage manufacturer (e.g. NetApp, Dell/EMC, HP, etc.).
Scales; bricks can be easily added to increase storage capacity
Performs; I/O is spread across multiple spindles (HDDs), thereby increasing read and write performance
Integrates well with RHEL/CentOS 7; if your organization is using RHEL 7, Gluster (GFS) integrates extremely well with that baseline, especially since it's come under the Red Hat portfolio of tools.
Documentation; using readthedocs demonstrates that the Gluster project isn't always kept up-to-date as far as documentation is concerned. Many of the guides are for previous versions of the product and can be cumbersome to follow at times.
Self-healing; our use of GFS required the administrator to trigger an auto-heal operation manually whenever bricks were added/removed from the pool. This would be a great feature to incorporate using autonomous self-healing whenever a brick is added/removed from the pool.
Performance metrics are scarce; our team received feedback that online RDBMS transactions did not perform well on distributed file systems (such as GFS), however this could not be substantiated via any online research or white papers.
Gluster is a lot lower cost than the storage industry leaders. However, NetApp and Dell/EMC's product documentation is (IMHO) more mature and hardened against usage in operational scenarios and environments. Using Gluster avoids "vendor lock-in" from the perspective on now having to purchase dedicated hardware and licenses to run it. Albeit, should an organization choose to pay for support for Gluster, they would be paying licensing costs to Red Hat instead of NetApp, Dell, EMC, HP, or VMware. It could be assumed, however, that if an organization wanted to use Gluster, that they were already a Linux shop and potentially already paying Red Hat or Canonical (Debian) for product support, thereby the use of GFS would be a nominal cost adder from a maintenance/training perspective.
