Over the past several years I have done an annual post about IBM and their XIV storage system and this is the fourth in what has become a series. You can read the first one here, the second one here, and last years here and here after the announcement of the IBM V7000.
IBM XIV Gen3
IBM recently announced the generation 3 or Gen3 version of XIV along with releasing for the first time public performance comparison benchmarks using storage performance council (SPC) throughout SPC2 workload.
The XIV Gen3 is positioned by IBM as having up to four (4) times the performance of earlier generations of the storage system. In terms of speeds and feeds, the Gen3 XIV supports up to 180 2TB SAS hard disk drives (HDD) that provides up to 161TB of usable storage space capacity. For connectivity, the Gen3 XIV supports up to 24 8Gb Fibre Channel (8GFC) or for iSCSI 22 1Gb Ethernet (1 GbE) ports with a total of up to 360GBytes of system cache. In addition to the large cache to boost performance, other enhancements include leveraging multi core processors along with an internal InfiniBand network to connect nodes replacing the former 1 GbE interconnect. Note, InfiniBand is only used to interconnect the various nodes in the XIV cluster and is not used for attachment to applications servers which is handled via iSCSI and Fibre Channel.
IBM and SPC storage performance history
IBM has a strong history if not leading the industry with benchmarking and workload simulation of their storage systems including Storage Performance Council (SPC) among others. The exception for IBM over the past couple of years has been the lack of SPC benchmarks for XIV. Last year when IBM released their new V7000 storage system benchmarks include SPC were available close to if not at the product launch. I have in the past commented about IBMs lack of SPC benchmarks for XIV to confirm their marketing claims given their history of publishing results for all of their other storage systems. Now that IBM has recently released SPC2 results for the XIV it is only fitting then that I compliment them for doing so.
Performance workload simulation results can often lead to applies and oranges comparisons or benchmark brouhaha battles or storage performance games. For example a few years back NetApp submitted a SPC performance result on behalf of their competitor EMC. Now to be clear on something, Im not saying that SPC is the best or definitive benchmark or comparison tool for storage or other purpose as it is not. However it is representative and most storage vendors have released some SPC results for their storage systems in addition to TPC and Microsoft ESRP among others. SPC2 is focused on streaming such as video, backup or other throughput centric applications where SPC1 is centered around IOPS or transactional activity. The metrics for SPC2 are Megabytes per second (MBps) for large file processing (LFP), large database query (LDQ) and video on demand delivery (VOD) for a given price and protection level.
What is the best benchmark?
Simple, your own application in as close to as actual workload activity as possible. If that is not possible, then some simulation or workload simulation that closets resembles your needs.
Does this mean that XIV is still relevant?
Does this mean that XIV G3 should be used for every environment?
Generally speaking no. However its performance enhancements should allow it to be considered for more applications than in the past. Plus with the public comparisons now available, that should help to silence questions (including those from me) about what the systems can really do vs. marketing claims.
How does XIV compare to some other IBM storage systems using SPC2 comparisons?
Cost per SPC2
In the above comparisons, the DS5300 (NetApp/Engenio based) is a dual controller (4GB of cache per controller) with 128 x 146.8GB 15K HDDs configured as RAID 5 with no discount applied to the price submitted. The V7000 system which is based on the IBM SVC along with other enhancements consists of dual controllers each with 8GB of cache and 120 x 10K 300GB HDDs configured as RAID 5 with just under a 40% discount off list price for system tested. For the XIV Gen3 system tested, discount off list price for the submission is about 63% with 15 nodes and a total of 360GB of cache and 180 2TB 7.2K SAS HDDs configured as mirrors. The DS8800 system with dual controllers has a 256GB of cache, 768 x 146GB 15K HDDs configured in RAID5 with a discount between 40 to 50% off of list.
What the various metrics do not show is the benefit of various features and functionality which should be considered to your particular needs. Likewise, if your applications are not centered around bandwidth or throughput, then the above performance comparisons would not be relevant. Also note that the systems above have various discount prices as submitted which can be a hint to a smart shopper where to begin negotiations at. You can also do some analysis of the various systems based on their performance, configuration, physical footprint, functionality and cost plus the links below take you to the complete reports with more information.
Bottom line, benchmarks and performance comparisons are just that, a comparison that may or may not be relevant to your particular needs. Consequently they should be used as a tool combined with other information to see how a particular solution might be a fit for your specific needs. The best benchmark however is your own application running as close to possible realistic workload to get a representative perspective of a systems capabilities.
Ok, nuff said