Flash storage: Guide to enterprise all-flash storage arrays
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The Hopkinton, Mass.-based storage giant positions its EMC XtremIO product for customers looking for predictable low-latency performance and scalability across a broad set of workloads. EMC acquired Israel-based XtremIO in May 2012, and the first XtremIO all-flash array became generally available in November 2013.
VNX-F -- the all-flash version of the VNX midrange array family -- also shipped in November, featuring a new flash-optimized VNX2 multicore software architecture. VNX-F targets customers who want the performance characteristics of an all-flash system yet prioritize price per GB and price per IOPS, according to Aaron Chaisson, director of cross business product marketing at EMC.
"EMC offers all-flash that address a number of different price points, use cases, applications, deployment scenarios and workloads," Chaisson wrote in an email.
EMC listed the VNX-F price per GB as less than $5 for a system with 46.2 TB raw capacity but declined to provide the price per GB of the XtremIO array. EMC also declined to provide information on price per IOPS for either product. Company representatives said pricing for the least expensive configuration of the XtremIO array starts at $200,000, and the least expensive configuration of the VNX-F with 10.8 TB raw capacity has a list price of less than $240,000. A new XtremIO entry configuration option starting at 5 TB raw capacity (3.3 TB usable) and 70 TB usable logical capacity will be available in July, according to Fenselau.
The XtremIO all-flash array had limited availability in April 2013, although its general availability date was November. The product has 10 TB and 20 TB scaling units called X-Bricks that use enterprise-grade multilevel cell flash (eMLC) and can scale to 80 TB clusters.
"The advantage of the scale-out architecture is you can scale further as we qualify 8-brick and 16-brick clusters, and the performance increases linearly," said Andy Fenselau, senior director of product and solutions marketing at EMC's XtremIO business unit, via an email, noting that capacity wasn't the only metric that would expand. He said the eight-brick qualification is expected by year's end, with plans for the 16-brick to follow in 2015.
Features added with the XtremIO generally available release included thin provisioning, inline data deduplication and support for 8 Gbps Fibre Channel and 10 GbE iSCSI connectivity. Updates added this month include snapshots, data-at-rest encryption and support for REST-based APIs and an OpenStack driver, according to EMC.
Those additional features will help XtremIO to catch up to many other all-flash arrays that beat EMC to market. EMC's VNX-F notably lacks data encryption and in line deduplication.
Replication support in the VNX-F and XtremIO products is available through for-fee add-ons. VNX offers replication and three data center replication through a Remote Protection Suite. Another option for replication is the for-fee Local Protection Suite, which also supplies snapshots. XtremIO supports replication and three data center replication through EMC's VPLEX and by running VPLEX in combination with RecoverPoint. Later this year, XtremIO plans to add support for replication through RecoverPoint alone, according to Fenselau.
Fenselau said discounted "frame" pricing is available for VPLEX. He added that many EMC customers have standardized on VPLEX and RecoverPoint. He said he views replication support via additional for-fee products in the same way as vendors that provide array-based replication or any data service for an additional charge.
The XtremIO array stands out in performance, with maximum read IOPS of 1,200,000 IOPS for a random workload at 4K block size, and the VNX-F was notable in throughput at 17.68 GBps for reads with a large-block, sequential workload.
The XtremIO product is among the minority of all-flash arrays to use custom-built RAID technology. Fenselau said the XtremIO Data Protection (XDP) was built from the ground up for flash and performs better than RAID 10 while minimizing flash writes with an 8% capacity overhead.
Fenselau said the XtremIO all-flash array has more than 200 customers. EMC declined to supply customer information for VNX-F other than to say that current product use cases include virtual servers, virtualized databases, virtual desktop infrastructure (VDI), test and development environments, online transaction processing (OLTP) applications, business intelligence and billing systems.
"EMC has never been a company to shy away from having some overlap in its portfolio," said Mark Peters, a senior analyst at Milford, Mass.-based Enterprise Strategy Group Inc.
EMC said there is an average performance degradation of 20% during XtremIO controller failure. The vendor did not disclose the degradation percentage for the VNX-F.