EMC finally made its XtremIO all-flash array platform generally available today, 18 months after it acquired XtremIO...
and eight months after the system went into limited availability.
XtremIO's architecture uses what the company calls X-Bricks. Each X-Brick holds up to 25 multi-level cell-based solid-state drives (SSDs) for a maximum of 10 TB (7.5 TB usable), and four X-Bricks can go into a cluster for 40 TB of raw capacity. EMC claimed one four-brick cluster can handle 250 TB of effective capacity with the array's inline deduplication, but dedupe ratios always vary according to data type. One XtremIO cluster can include two to eight controllers and up to 128 cores.
Josh Goldstein, vice president of product management for XtremIO, said 20 TB X-Bricks will be available in early 2014 for up to 80 TB of raw capacity per cluster. One brick is 6u and two bricks are 12u, but a four-brick cluster takes up 22u of space.
EMC claimed each brick delivers up to 150,000 IOPS with 50% 4k random reads and 50% writes, and 300,000 IOPS with 100% 4k random reads. Performance scales linearly.
"Getting high performance from flash is not hard," Goldstein said. "Getting consistent and predictable numbers is difficult."
Along with dedupe, XtremIO features include content-based data placement and XtremIO Data Protection (XDP). XDP is an algorithm EMC claimed will allow SSDs to fail without data loss, preventing performance degradation.
Goldstein said XDP removes the need to immediately replace a failed drive if there is extra space on other SSDs in the brick. "There are no hot spares," he said. "That's important with flash because you don't have any idle devices."
EMC claimed XDP requires an 8% capacity overhead, compared to a 20% to 50% overhead for popular RAID schemes.
XtremIO has no array-based replication, although Goldstein said that will likely be available next year. Another missing feature is pricing -- EMC has not given pricing for XtremIO; it has only claimed it will be competitive with other flash arrays.
All-flash field already crowded
While EMC has sold SSDs alongside hard drives in its storage platforms for years, this is its first all-flash array. While EMC was getting XtremIO ready for prime time, newcomers such as Violin Memory, Nimbus Data, Pure Storage, Skyera and SolidFire launched all-flash arrays -- several generations of them in some cases.
Among the major vendors, IBM has its FlashSystem platform based on its Texas Memory Systems acquisition, and Hitachi Data Systems (HUS VM), Hewlett-Packard (3PAR StoreServ), Dell (Compellent) and NetApp (E-Series) have developed all-flash versions of traditional arrays.
Wikibon analyst Stu Miniman said despite just becoming generally available today, XtremIO is really a second-generation product because of its extensive testing. XtremIO was close to releasing the system before the EMC acquisition, but EMC held back general availability (GA) until it could do more testing.
"We knew it wasn't a GA product when EMC bought it," Miniman said. "A first-version product for a startup is different than a first-version product for EMC."
He said besides overlap with its VMAX enterprise array platform, a challenge for EMC will be to add enterprise features such as replication to XtremIO.
User verdict: Good performance, ease of use; waiting for replication
After more than a year of beta testing, Latham, N.Y.-based consulting firm CMA is using XtremIO as back-end storage for its Oracle RAC database clusters, called MicroTerabytes. CMA Chief Data Warehouse Architect Brian Dougherty said his company will also incorporate XtremIO in its data centers.
CMA has traditionally used high-end enterprise storage such as EMC VMAX, IBM DS series and Hitachi Data Systems USP and VSP.
Dougherty said he also tested Hewlett-Packard's 3PAR StoreServ all-flash arrays and considered other flash arrays before selecting XtremIO. He said key drivers were the way XtremIO's performance scaled linearly as he added a second brick, and its ability to deliver the same performance he could get from enterprise arrays in a smaller footprint.
"We had flash in our VMAX, but we felt XtremIO was built from the ground up to support flash and not a traditional array that happens to have SSDs in it," Dougherty said. "It was built for flash at the controller and operating system level."
He said besides meeting his rigorous performance needs in testing -- a two-brick node delivered 500,000 IOPS at a 4K block level -- he found XtremIO simple to use. "We have over a petabyte of storage in our data center now, so we want a product we can deploy in hours or in a day, at most. The form factor was also important, and of course, we needed the same throughput or the Oracle RAC cluster would not scale."
XtremIO has a three-pane interface for deploying storage volumes. Users create volumes in the left pane, create initiator groups in the right pane, and map them from the middle pane.
"With VMAX, we spent a lot of time carefully laying out location, RAID types, the number of members in a volume [and] the volume size -- and there's a lot of work on the front side, too," Dougherty said. "All of that work goes away with XtremIO."
Dougherty said he expects EMC to address his two biggest XtremIO complaints next year -- one being the density size. He will be happy to see the 20 TB X-Bricks because "with two bricks now we have 15 [usable] terabytes. We'll have excess power in those two bricks, but we'll consume the storage."
Dougherty said he has also asked for array-based replication for XtremIO, and he expects EMC to add RecoverPoint support. "All of our data centers are seven-by-24, mission-critical, and we have DR [disaster recovery] centers. We can't deploy them in our data centers unless we can replicate them over the wire to another data center. Now we have to use our application replication instead of replicating through the storage."