DCIG mid-market array guide: Why we left those companies out
Three levels of in and out filtering used to produce buyers' list
Analysis Conversations with DCIG have revealed why seemingly obvious companies and their products were left out of a mid-range storage array buyers' report.
DCIG analyst Ken Clipperton told us about the inclusion/exclusion criteria DCIG used when compiling its report.
The initial criteria for selecting suppliers and products were:
- Must be available as an appliance that includes its own hardware and software
- Must be a traditional or hybrid array (the product must support a configuration that includes hard disk drives)
- Must support a dual, redundant controller configuration
- Must not be marketed as scale-out NAS
- Must not be marketed as an all-flash array (AFA)
The first criterion rules out storage software provided only as software, such as DataCore and Nexenta.
Three additional filters were then applied to the resulting set of suppliers and products:
- Must support one or more block-based (SAN) storage protocols
- Maximum raw capacity of no more than 500 TB
- Must be generally available on July 1, 2016
The block-based requirement ruled out Tintri.
The 500TB limit ruled out products from HDS, Huawei, IBM, Lenovo, and NetApp. Despite them all having systems below 500TB in capacity, because all of them scaled past 500TB they were excluded*. To our surprise, when we checked, we found this was true. For example, no NetApp FAS array scales to less than 500TB – they all go beyond that capacity. Ditto HDS, etc.
Nexsan arrays were excluded, despite meeting all the first and second-level criteria, because there was a third filter, a DCIG ranking filter.
Clipperton explains: "The arrays that met DCIG’s inclusion criteria and achieved a ranking of Recommended, Excellent or Good were included in the published, downloadable Buyer’s Guide. These rankings are based on standard deviation (STDEV) ranges in product feature scores, and translate to a range of 2.0 to -0.5 STDEV. Products that scored below -0.5 STDEV DCIG ranks as Basic and were not included in the published, downloadable Buyer’s Guide."
That was the reason why Nexsan wasn't included in the DCIG 2016-17 Midmarket Enterprise Storage Array Buyer’s Guide.
DCIG is about to launch the second phase of its research on enterprise storage arrays that will add NAS-only and AFA products to the ESABR (Enterprise Storage Array Body of Research) database, which will result in a number of new Buyer’s Guide Editions based upon that research. ®
(El Reg storage desk gently opines that there has to be a cut-off but we think a more realistic criterion might be to include all systems between, say, 100TB and 500TB, irrespective of whether they scale past 500TB.)