What kind of raid is drobo

Desired protection level change requires a destroy-and-rebuild process. There are time and potential data integrity issues with this process. BeyondRAID allows administrators to mix and match drives of different sizes. Through the creative use of this new technology, Drobo can make more effective use of drives of varying sizes than traditional RAID systems. In many traditional RAID systems, if you have to move a storage array, you need to be extremely careful to make sure that disks are removed and put back in the exact same order.

With the click of a mouse, you can change your BeyondRAID protected system from single to dual-drive protection, assuming that you have enough free disk space to make the change. When a disk fails in a traditional RAID set, you replace it. If you need to expand the size of a traditional RAID set, you replace the disks one at a time, do a rebuild each time, and eventually expand the volume.

With BeyondRAID, you can replace any disk at any time and even replace smaller disks with bigger ones. The possibility to recover Drobo data directly depends on whether you have the map or not. Physically, the map is stored in two copies or three copies to satisfy redundancy requirements of the pack, so if you have a physical failure, you do not lose the map immediately.

Logically, all the copies are updated simultaneously, so if something goes wrong with the map, the bad change affects all the physical copies at the same time, and there are no historical records of any kind to find out past states. There are three main reasons your Drobo device can fail: box failure, disk failure, and filesystem failure.

This includes cases when Drobo disks are healthy, but apparently, something is wrong with the box. In these cases, recovery is quite simple — you need to take the disks out and place them to another compatible Drobo box, preferably the same model box replaced under warranty.

This includes cases when you lost more disks than your Drobo fault-tolerance allows. The recovery result depends on:. Another Drobo failure is a filesystem failure including an operating system failure on the host PC for Drobo DAS where the operating system controls the Drobo filesystem.

File deletion and Drobo volume formatting also belong to this type of failure. Drobo data recovery in case of such a failure is very complicated. The difficulties are associated with thin provisioning in general and how it is implemented in Drobo in particular.

Modern thin provisioning implementations use TRIM to detect which data blocks are no longer used by a filesystem. All that TRIM does is to inform a device what data blocks should be forgotten according to a current filesystem state.

That is why Drobo developers had to invent another mechanism for determining what blocks are used and what are free. They came up with making Drobo aware of the filesystem or several filesystems stored on the disk pack. Drobo can peek into a filesystem metadata to get the list of occupied and free blocks so that to discard the unused blocks from the map.

Since the technology works at the block level, it can write blocks of data that alternate between RAID protection levels. If you need to add storage capacity to a Drobo, simply insert additional disk drives or replace the smallest disks with larger ones — no need to change RAID levels, purchase a new storage array, or go through the complex administration of pooling RAID groups.

This ensures enterprise-level dual parity data protection, when needed. If a drive happens to fail, Drobo will automatically re-layout the data to the remaining drives, returning it to a protected state with no user interaction.

Thin Provisioning with Smart Volumes Our volumes are just smarter. Space allocation is automatically managed, maximizing storage resources. For example, if a large file on a volume is deleted, the free space of the Drobo gets larger.

The freed up space is then available to other volumes.