This is all about the selling you a "Device" and prices vary greatly between resellers. The devices work well, but the pure cloud solutions need a lot of work.
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.
SQL Backups just don't work reliably. For us, we lost all of our SQL data backed up through the CTERA Application process. Although the logs indicated a success, that was really not the case. This came close to putting us out of business. Luckily I had taken a genuine SQL backup to a folder. Unfortunately it was a month old. We had to pick-up the pieces from there.
Don't use it for file sync and share. There are better products out there i.e. anchorworks.com
Support sucks. Good luck with response time and answers that are inconsistent between team members. For example I had to rebuild a VM from scratch. When I re-installed the CTERA client It obviously thought I was adding another device. When I inquired to tech support, one member said "copy the old Data folder" (I still had the old VHD. That did not work). The other directed me to the correct spot to just change the associated folder. The turn-around time was over 24 hours for this simple fix.
Documentation, plenty of fodder but no real tech there.
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.
Unfortunately CTERA does not stack up well if you want a pure cloud BDR. I have use iDrive and Asigra. iDrive has similar support and SQL backup issues. Asigra can vary widely in support and price, but the software is solid.
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.
