Welcome Chicago, the windy release

It has been a while since the Open vStorage team released an Open vStorage version. From now Open vStorage releases will carry a name instead of a number. The latest release is called Chicago. The nickname of Chicago, the windy city, is appropriate for this release as with the new cache tuning features Open vStorage is velocious. Just to say that this release has some long anticipated features:

Flex SSD layout:
We have been working towards this feature since May but finally it is ready. You now have the flexibility to configure how you want to use you SATA, SSDS and PCIe cards through the GUI. For example you can use the SATA drives in your ALBA Backend, the SSDs as read cache devices and the PCIe card to accelerate the writes. To achieve this, every Storage Router displays the detected drives (SATA, SSD, …) and allows to assign roles to the drives. Currently there are 4 roles:

  • DB: The DB role stores the distributed database and metadata of the volumes. The DB role must be assigned to an SSD. This will reserve 10% of the SSD for the distributed database. All storage Routers must have at least one disk with the DB role.
  • Scrub: The scrubber is the application which does the garbage collection of snapshot data which is out of the retention. This will reserve 300 GB of space. All storage Routers must have at least one disk with the scrubbing role.
  • Read: This will allow to use the disk as read cache.
  • Write: This will allow to use the disk as write cache.

You can now assign a part of an SSD to be used as read or/and write cache by a specific vPool. To assign a role to a disk, click the gear icon and select the appropriate role from the dropdown.

Tune the cache:
Open vStorage now exposes a whole set of caching parameters for a vDisk. You can configure if you want to use the Distributed Transaction Log (DTL), whether to Cache on Read or Write, if a volume should use the deduped cache or not and what the SCO size and amount of outstanding data in the write buffer can be before throttling occurs. You can even set how much each individual vDisk may consume of the read cache. These options makes Open vStorage the most configurable storage solution in the field.

The DTL over RDMA:
The Distributed Transaction Log (DTL) is making sure that you don’t have data loss when a host goes down by storing incoming writes also on another host. With the Chicago release you can use low-latency RDMA technology to increase the performance of the DTL.

Move to GitHub:
The source of Open vStorage can from now on be found on GitHub. In a nutshell, Open vStorage has had 3,623 commits made by 33 contributors representing 113,455 lines of code and took an estimated 29 years of effort (COCOMO model). How cool is that!