David Vellante with Josh Krischer Late in 2007, IBM acquired Israeli-based XIV, a small company headed by the father of EMC’s Symmetrix, storage industry technology icon Moshe Yanai. At the time, IBM touted XIV as appropriate for so-called cloud computing and Internet applications, positioning XIV as incremental to products in IBM’s storage portfolio. test
At the time of the announcement, the Wikibon community consensus was that while the XIV acquisition was intriguing, it wasn’t cause for any immediate customer action (see IBM's Acquisition of XIV) and did not in fact appear to be well suited for the cloud. Rather, the community felt it would be positioned as a general purpose system, directly competing for large segments of data center storage that did not require the very highest performance. Furthermore, the community’s analysis suggested that XIV was important as its technology offered many attributes of emerging architectures, including virtualization and thin provisioning, combined with a methodology to spread data across all the drives in an array, in a manner reminiscent of 3PAR or even the Google File System, all while using standard off-the-shelf components. The most important aspect of the announcement at the time however was that XIV was now part of IBM’s enormous franchise. Placing an innovative product line in IBM’s portfolio was newsworthy and potentially significant. Earlier this month, perhaps mistakenly, IBM unveiled certain details of version 2 of XIV on its Web site. Also, reports from the field suggest that IBM has formed a special ‘Tiger Team,’ in part comprised of former EMC sales reps, to secure early customers beyond XIV’s initial customer base, which included several banks in Israel. Announcement activity has primarily been concentrated in Europe with virtually no comments from IBM’s U.S. storage groups.
What is unique about XIV? Several attributes of IBM’s XIV were made clearer with this quiet release, including:
- XIV is the Model-T of storage arrays and currently comes in one flavor only; a 180TB mirrored configuration offering users approximately 90TB of storage. The system is always shipped fully populated. The only option seems to be the power cord.
- The array is comprised of standard components – 1TB SATA drives, processors, cache, Ethernet cards, FC, and iSCSI ports are all off-the-shelf.
- The XIV architecture is fully virtualized, supports thin provisioning and is optimized for extremely high capacity utilization, super low cost, and simplicity. Each volume is split into 1GB pages, and data is spread across all devices in the array. The system is designed for ease-of-use and is self-tuning, similar to 3PAR’s approach.
What’s missing from the XIV’s approach?
- Since all drives are used to read and write volumes, mixing different drive capacities within a single XIV rack is not supported and doesn’t make sense, making tiered storage an unlikely feature.
- Tier 0 (using flash) is not supported and also doesn’t make sense with the current architecture.
- Spindown is also not supported and doesn’t make sense since I/O’s are evenly distributed across all drives.
- All 180 drives must be used. Configurations smaller than 180TB (mirrored) are only supported by allowing users to use less capacity on each disk drive, with the proviso of locking customers in to future capacity increments.
- Asynchronous remote copy is an apparent gap in the offering.
Clustering between racks will allow XIV to address these shortcomings, expanding configuration options and enabling the mixing of racks with different drive performance characteristics.
How energy efficient is XIV?
A simplistic analysis of energy efficiency suggests that because of the need to fully mirror, its ‘brute force’ use of standard components, and its UPS approach, the environmental profile of XIV appears substantially less attractive than that of competitive offerings. A like-to-like comparison using similar cache and drive capacities suggests that the four-year environmental costs (power, cooling, space) of a mirrored XIV (180TB raw) approach $59,000 while the industry average for competitive mirrored products is around $40,000. Using RAID 5 would lower the competitive costs to around $27,000. Because XIV does not support RAID 5, a like-to-like comparison cannot be made here. The caveat of this analysis is the degree to which the expected higher utilization of XIV will offset some of these disadvantages. However, customers should not purchase XIV solely for its environmental characteristics.
How can customers exploit such an architecture?
The Wikibon community sees four main opportunities for customers to take advantage of approaches typified by XIV:
- By utilizing XIV to perform near CDP.
- By driving increased simplicity. Because XIV spreads data across all devices and manages performance automatically, customers’ performance tuning tasks will be much simpler.
- By carving out the ‘fat middle.’ By exploiting high utilization and low cost components, it would seem XIV is best positioned below Tier 1A and above archiving.
- By negotiating hard for a lower purchase price. XIV is designed to be inexpensive, with reports of $3-$4/GB raw. This is considerably lower than most purpose-built arrays although higher than products such as EMC’s Hulk and HP’s Extreme storage, which don’t have the same function as XIV. Thus IBM is in the position to undercut the competition in its class.
What does this announcement mean for competitors?
In the near term, the product lacks scalability and has the usual inherent new design risks. The Wikibon community believes clustering will make or break XIV, and if IBM can get this capability to work, it will have a fantastic product. Internally to IBM this product could cause immense chaos. It appears that XIV could be positioned to replace midrange products as well as IBM’s DS8000 and DS4000 over time. Longer term, XIV’s spread-everywhere approach and simple storage management bear watching and, along with architectures from the likes of 3PAR, Compellent, Pillar, and others, will collectively pressure users to carefully consider alternatives to traditional storage management approaches. The economics of XIV also bear watching as it represents perhaps the most cost-effective general purpose architecture we’ve seen to date.
Action Item: With XIV, IBM is signaling that it has an increased appetite for storage R&D. To make its investments pay off, IBM is combining a low-cost, volume commodity approach with an innovative architecture that is aimed at the sweet spot of the data center. Unfortunately it’s not quite ready for prime time. Users should kick the tires of XIV to determine the degree to which automated performance management will change storage administration best practice. The bottom line on XIV is it legitimizes fully virtualized architectures. The question users should answer on XIV is do the lower acquisition costs and simpler management attributes warrant the substantial migration costs and risks of moving from existing platforms.
Action Item:
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