Hybrid array explained

A 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.

Implementations

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
• IBM Flash Cache Storage Accelerator (FCSA) server software^[7]
• Intel's Smart Response Technology for desktop
• Intel's Cache Acceleration Software for servers and workstations
• LSI CacheCade software for their controllers^[8]
• Marvell's HyperDuo controllers^[9]
• Microsoft's Automated Tiering (since Windows 2012 R2)
• NetApp's Flash Cache, Flash Pool, Flash Accel^[10]
• Oracle Corporation markets products such as Exadata Smart Cache Flash, and the FS1 flash storage system.^[11]
• Microsoft ReadyBoost allows personal computers to USB flash drives as cache.
• Nvelo DataPlex SSD caching software was announced in 2011,^[12] and was acquired by Samsung in 2012.^[13]
• SanDisk FlashSoft for Windows, Linux, and vSphere^[5]
• Products are offered by vendors like AMI StorTrends,^[14] Tegile Systems, Reduxio, and Tintri.^[15]
• ZFS using hybrid storage pools, are used for example in some Oracle Corporation products.^[16]

See also

• Hybrid drive built-in flash cache, handled by firmware
• Automated tiered storage another name for hierarchical storage management
• The "five-minute rule" for caching

Notes and References

1. Book: Rino Micheloni. Alessia Marelli. Kam Eshghi. Inside Solid State Drives (SSDs). 2012. Springer. 978-94-007-5145-3. 62.
2. Web site: Charlie Demerjian . Adaptec's MaxIQ caches RAIDs with SSDs . SemiAccurate . September 9, 2009 . October 10, 2016 .
3. Web site: Larry Dignan . EMC unveils VFCache, targets Fusion-io . https://web.archive.org/web/20120206220809/http://www.zdnet.com/blog/btl/emc-unveils-vfcache-targets-fusion-io/68657 . dead . February 6, 2012 . ZDNet . Between the Lines . February 5, 2012 . October 10, 2016 .
4. News: One day later: EMC declares war on all-flash array, server flash card rivals: Rolls out XtremIO array, renamed VFCache . March 5, 2013 . The Register . Chris Mellor . October 10, 2016 .
5. Web site: Fusion-io spins up ioTurbine, enhances server flash caching . The Register . October 10, 2016 .
6. Web site: Fusion-io buys NexGen. theregister.co.uk . 2015-03-26.
7. Web site: The SSD Guy . IBM Adds Server-Side Caching . The SSD Guy . 2013-08-20 . 2013-12-23.
8. Web site: LSI MegaRAID CacheCade Pro 2.0 Review. 2015-03-26. storagereview.com. 2015-04-02. https://web.archive.org/web/20150402105452/http://www.storagereview.com/lsi_megaraid_cachecade_pro_20_review. dead.
9. Web site: Hands-on with the Marvell HyperDuo hybrid storage controller . 2015-03-26 . CBS Interactive. CNET.
10. Web site: NetApp: Flash as a STORAGE tier? You must be joking . 2015-03-26 . theregister.co.uk.
11. News: Oracle crashes all-flash bash: Behold, our hybrid FS1 arrays: Mutant flash/disk box a pillar of storage: It's axiomatic . September 30, 2014 . The Register . Chris Mellor . October 10, 2016 .
12. Web site: NVELO Dataplex SSD Caching Software Review - Seven mSATA SSDs Prove An Amazing Concept . The SSD Review . December 4, 2011 . Les Tokar . October 10, 2016 .
13. Web site: Samsung Acquires SSD Caching Company NVELO . AnandTech . Kristian Vättö . December 16, 2012 . October 10, 2016 .
14. Web site: Ian Barker . AMI StorTrends 3500i offers high performance storage for smaller enterprises . BetaNews . 2014-01-27 . 2014-10-17.
15. Web site: Mutant array upstarts feast on EMC, NetApp's leavings. 2015-03-26 . The Register .
16. Web site: Oracle's Flash-Friendly Sun ZFS Storage Is Ready for New SPARCs. 3 April 2013 . 2015-03-26 . enterprisestorageforum.com.