The Unity platform offers a range of storage efficiency features that can help you maximize the utilization and performance of your system. Unity’s operating environment was built with the capability of multicore processors and their increasing scale in mind. With the use of flash media in hybrid array configurations, FAST cache and FAST VP can ensure that data is readily accessible and is being stored in the proper location on the array. Lastly, host I/O limits can be implemented to manage host activity and control “noisy neighbors.”
A set of multicore optimizations is offered on the Unity system:
- Multicore cacheWith multicore cache, read and write cache space is
shared and dynamically manipulated based on the read/write activity
served by the system. This ensures a proper distribution of cache
resources to best serve incoming requests. The arrival rates of incoming requests are tracked and weighed against the ability of the back-end disks
to write the data out of cache. Based on this information, multicore cache throttles arrival rates to avoid forced flushing. Multicore cache is fully automated. No user interaction is required to enable or manipulate the cache.
- Multicore RAIDMulticore RAID manages the RAID-based protection on storage pools. With multicore RAID, any unassigned disks are marked as potential spares for use in the event of a drive fault. If a drive becomes faulted, a potential spare is selected and becomes a permanent part of the RAID group. Multicore RAID can also move a disk within the physical locations of a system. For example, a disk can be moved from one enclosure to another to better balance activity between enclosures and buses. Both assigned and unassigned disks can be relocated within a five-minute window. Note that moving an assigned disk temporarily results in a degraded RAID group. Lastly,
RAID 6 groups that suffer double drive failures employ a parallel
rebuild to restore full redundancy as quickly as possible. Spares are
selected and the rebuild process begins immediately following a drive fault.