Hybrid array

hybrid array is a form of hierarchical storage management that combines hard disk drives (HDDs) with solid-state drives (SSDs) for I/O speed improvements.

Hybrid storage arrays aim to mitigate the ever increasing price-performance gap between HDDs and DRAM by adding a non-volatile flash level to the memory hierarchy.[1] Hybrid arrays thus aim to lower the cost per I/O, compared to using only SSDs for storage. Hybrid architectures can be as simple as involving a single SSD cache for desktop or laptop computers, or can be more complex as configurations for data centers and cloud computing.


Some commercial products for building hybrid arrays include:

  • Adaptec demonstrated the MaxIQ series in 2009.[2]
  • Apple’s Fusion Drive
  • Linux software includes bcache, dm-cache, and Flashcache (and its fork EnhanceIO).
  • Condusive’s ExpressCache is marketed for laptops.
  • EMC Corporation VFcache was announced in 2012.[3][4]
  • Fusion-io acquired ioTurbine in 2011,[5]and the product line it acquired by buying NexGen in 2013.[6]
  • Hitachi Accelerated Flash Storage (HAFS) used together with the Hitachi Dynamic Tiering software[7]
  • IBM Flash Cache Storage Accelerator (FCSA) server software[8]
  • Intel’s Smart Response Technology for desktop
  • Intel’s Cache Acceleration Software for servers and workstations
  • LSI CacheCade software for their controllers[9]
  • Marvell’s HyperDuo controllers[10]
  • Microsoft’s Automated Tiering (since Windows 2012 R2)
  • NetApp’s Flash Cache, Flash Pool, Flash Accel[11]
  • Oracle Corporation markets products such as Exadata Smart Cache Flash, and the FS1 flash storage system.[12]
  • Microsoft ReadyBoost allows personal computers to USB flash drives as cache.
  • Nvelo DataPlex SSD caching software was announced in 2011,[13]and was acquired by Samsung in 2012.[14]
  • SanDisk FlashSoft for Windows, Linux, and vSphere[5]
  • Products are offered by vendors like AMI StorTrends,[15]Tegile Systems, Reduxio, and Tintri.[16]
  • ZFS using hybrid storage pools, are used for example in some Oracle Corporation products.[17]


  1. ^Rino Micheloni; Alessia Marelli; Kam Eshghi (2012). Inside Solid State Drives (SSDs). Springer. p. 62. ISBN 978-94-007-5145-3.
  2. ^Charlie Demerjian (September 9, 2009). “Adaptec’s MaxIQ caches RAIDs with SSDs”. SemiAccurate. Retrieved October 10, 2016.
  3. ^Larry Dignan (February 5, 2012). “EMC unveils VFCache, targets Fusion-io”. Between the Lines. ZDNet. Retrieved October 10, 2016.
  4. ^Chris Mellor (March 5, 2013). “One day later: EMC declares war on all-flash array, server flash card rivals: Rolls out XtremIO array, renamed VFCache”. The Register. Retrieved October 10, 2016.
  5. ^ Jump up to:ab “Fusion-io spins up ioTurbine, enhances server flash caching”. The Register. Retrieved October 10, 2016.
  6. ^“Fusion-io buys NexGen”. theregister.co.uk. Retrieved 2015-03-26.
  7. ^“Big storage turns the tide in the hybrid flash array market”, Computer Weekly, September 2013, retrieved 2015-03-26
  8. ^The SSD Guy (2013-08-20). “IBM Adds Server-Side Caching”. The SSD Guy. Retrieved 2013-12-23.
  9. ^“LSI MegaRAID CacheCade Pro 2.0 Review”. storagereview.com. Retrieved 2015-03-26.
  10. ^“Hands-on with the Marvell HyperDuo hybrid storage controller”. CNET. CBS Interactive. Retrieved 2015-03-26.
  11. ^“NetApp: Flash as a STORAGE tier? You must be joking”. theregister.co.uk. Retrieved 2015-03-26.
  12. ^Chris Mellor (September 30, 2014). “Oracle crashes all-flash bash: Behold, our hybrid FS1 arrays: Mutant flash/disk box a pillar of storage: It’s axiomatic”. The Register. Retrieved October 10, 2016.
  13. ^Les Tokar (December 4, 2011). “NVELO Dataplex SSD Caching Software Review – Seven mSATA SSDs Prove An Amazing Concept”. The SSD Review. Retrieved October 10, 2016.
  14. ^Kristian Vättö (December 16, 2012). “Samsung Acquires SSD Caching Company NVELO”. AnandTech. Retrieved October 10, 2016.
  15. ^Ian Barker (2014-01-27). “AMI StorTrends 3500i offers high performance storage for smaller enterprises”. BetaNews. Retrieved 2014-10-17.
  16. ^“Mutant array upstarts feast on EMC, NetApp’s leavings”. The Register. Retrieved 2015-03-26.
  17. ^“Oracle’s Flash-Friendly Sun ZFS Storage Is Ready for New SPARCs”. enterprisestorageforum.com. 3 April 2013. Retrieved 2015-03-26.


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