Tony Pearson is a Master Inventor and Senior IT Architect for the IBM Storage product line at the
IBM Executive Briefing Center in Tucson Arizona, and featured contributor
to IBM's developerWorks. In 2016, Tony celebrates his 30th year anniversary with IBM Storage. He is
author of the Inside System Storage series of books. This blog is for the open exchange of ideas relating to storage and storage networking hardware, software and services.
(Short URL for this blog: ibm.co/Pearson )
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Well, it's Tuesday again, and you know what that means? IBM announcements!
Today's announcements are all about the Storwize family, IBM's market-leading Software Defined Storage offerings. Having sold over 55,000 systems, and managing over 1.6 Exabytes of data, IBM continues to be the #1 leader in storage virtualization solutions. The Storwize family consists of the SAN Volume Controller (SVC), Storwize V7000, Storwize V7000 Unified, Flex System V7000, Storwize V5000, Storwize V3700 and V3500.
SAN Volume Controller 2145-DH8
The new 2145-DH8 model is a complete repackaging of this popular storage system. The previous model, the 2145-CG8, was 1U-high x86 server per node, and each node required a separate 1U-high UPS to provide battery protection for its cache. Nobody liked this. The new 2145-DH8 instead is a 2U-high node with two hot-swappable batteries, eliminating the need for UPS altogether. Thus, an SVC node-pair using the 2145-DH8 models takes up the same 4U space, but with fewer cables. The SVC can now also support standard office 110/240 voltage sources.
The new model sports an 8-core processor with 32GB RAM. Since these are 2-socket servers, IBM offers that option to add a second 8-core processor and additional 32GB RAM to help boost Real-time Compression. Each node can have optionally one or two hardware-assisted compression cards which use the Intel QuickAssist chip to boost compression performance.
While the Real-time Compression was in fact, real-time, performed in-line to the read/write I/O process, at latency comparable to uncompressed data for applications, the compression process on older models was entirely software-based, consuming some of the CPU resources, which lowered the maximum IOPS of the solution. With the added cores, added RAM, and hardware-assisted compression chips, IBM resolves that concern. In fact, the new 2145-DH8 with compression can provide more IOPS than an older 2145-CG8 without compression.
The previous model 2145-CG8 allowed you to put up to 4 small SSD drives in the node itself, which were treated the same as externally Flash drives for purposes of having a high-speed storage pool for select volumes, or automated sub-LUN tiering with Easy Tier. The new model 2145-DH8 allows you to attach up to 48 Solid State Drives (SSD) via 12Gb SAS cables. These are housed in the new 2U-high 24F enclosures that can offer up to 38.4 TB of Flash per SVC I/O group.
IBM also re-designed the host/device ports to use Hardware Interface Card (HIC) slots. In the 2145-CG8, you had four FCP ports, two 1GbE Ethernet ports, with options to add two 10GbE Ethernet ports or four additional FCP ports. If you had mostly an FCoE or iSCSI environment, you didn't need the FCP, and if you were mostly a FCP Storage Area Network (SAN) environment, then most of the Ethernet ports went unused. To solve this, the 2145-DH8 can allow you to have up to six HIC cards that are either FCP, Ethernet, or SAS. There are three 1GbE fixed Ethernet ports which can be used for iSCSI and administration.
If you have SVC today, you can upgrade non-disruptively by either swapping out your current SVC engines with the new 2145-DH8 engines, or you can add the new 2145-DH8 engines to your existing SVC cluster. Either way, there is no outage to your applications!
This is the next generation of the popular Storwize V7000. The previous generation had a 4-core processor and 8GB RAM per canister. The new model has an 8-core processor with 32GB of RAM per canister, with the option to double these to boost Real-time compression. There are two canisters per control enclosure, which gives you 64GB to 128GB of RAM per Storwize V7000 I/O group.
The new Storwize V7000 comes with one hardware-assisted compression chip on the mother board of each canister, with the option to add a second chip per canister.
Each canister offers three HIC slots, which can be used for the additional hardware-assist compression chip, FCP or Ethernet ports.
To accommodate these HIC slots, new canisters were needed. Instead of the flat wide style top and bottom, we now have taller, thinner canisters that sit side to side. This side-to-side design is similar to our existing Storwize V5000 and V3700 models.
The previous model could support up to 9 expansion enclosures per control enclosure. The Storwize V7000 can have up to 24 drives in its control enclosure, and now attach up to 20 expansion enclosures, which allows up to 504 drives per control enclosure, and up to a maximum of 1,056 drives per Storwize cluster.
If you have previous models of Storwize V7000, you can add the new Storwize V7000 into the same cluster, or virtualize the previous storage for migration purposes.
The new software applies new capabilities to both new generation hardware as well as the older models, so people with existing gear can benefit as well.
In prior releases, the sub-LUN automated tiering was limited to two levels: Flash and HDD. This lumped all 15K, 10K and 7200 RPM drives into a common HDD category. In the new v7.3.0 code, you can now have three levels: Flash, Enterprise HDD, and Nearline HDD, or two HDD levels: Enterprise and Nearline. The Enterprise level combines 15K and 10K RPM drives, similar to what is done on the IBM System Storage DS8000 disk systems.
The new code is also able balance your storage pools, and can be used with uniform or mixed storage pools to eliminate performance hot spots.
The new code has been enhanced to detect the hardware-assisted compression chip on the new SVC and Storwize V7000 models, and use those if available.
For the Storwize V3700 and V5000 models, the new code allows up to nine expansion enclosures per control enclosure. In the previous models, the V3700 allowed only four expansions, and the V6000 only six expansions per control enclosure. The V3700 can now support up to 240 drives, and the V5000 can support up to 480 drives.
IBM Storwize V7000 Unified File Module software v1.5
For Storwize V7000 Unified clients, there is new software for the File Modules that provide NFS, CIFS, FTP, HTTPS and SCP protocol capability. The new v1.5 code now adds NFS v4 and SMB 2.1 levels of support. Most NFS users are still on NFSv3, but about 20 percent of NFS users are using NFS v4 which offers stateful access. The SMB 2.1 for CIFS was introduced by Microsoft in Windows 7 and Windows Server 2008 R2.
Deterministic ID mapping allows you to map Windows userids to UNIX/Linux group and owner id numbers. In the past, the problem is that this mapping is different on each machine, so people often had to stand up a Windows System for Unix Services (SFU) server to provide consistent ID mapping. Now, with v1.5 code, you will no longer have to do this. The deterministic ID mapping will can now replicate the mapping to each machine without an SFU server.
Active Cloud Engine allows up to ten Storwize V7000 Unified to be connected across distance to form a single global name space. WAN caching, however, was restricted to a single site having write capabilities, while the others were read-only. In v1.5 release, IBM now supports multiple independent writers at different locations on the same fileset.
Security enhancements include multi-tenancy, configurable password policies, session policies, and hardened boot and SSH configurations. With NFS v3/v4, you can now use [Kerberos] for security.
Finally, I am please to see that we now have Cinder support for files on the Storwize V7000 Unified on the OpenStack Havana release that just came out last month. The OpenStack Cinder interface can assign LUNs to virtual machines, but the new Havana release allows NAS systems to dole out files that act as LUNs, such as OVA or VMDK files. The advantage is that these files can managed by Active Cloud Engine, cached locally across global name space, have policies place them on appropriate storage tiers, and inactive Virtual Machine images can be migrated to less expensive disk or tape.
Wrapping up my coverage of the annual [2010 System Storage Technical University], I attended what might be perhaps the best session of the conference. Jim Nolting, IBM Semiconductor Manufacturing Engineer, presented the new IBM zEnterprise mainframe, "A New Dimension in Computing", under the Federal track.
The zEnterprises debunks the "one processor fits all" myth. For some I/O-intensive workloads, the mainframe continues to be the most cost-effective platform. However, there are other workloads where a memory-rich Intel or AMD x86 instance might be the best fit, and yet other workloads where the high number of parallel threads of reduced instruction set computing [RISC] such as IBM's POWER7 processor is more cost-effective. The IBM zEnterprise combines all three processor types into a single system, so that you can now run each workload on the processor that is optimized for that workload.
IBM zEnterprise z196 Central Processing Complex (CPC)
Let's start with the new mainframe z196 central processing complex (CPC). Many thought this would be called the z11, but that didn't happen. Basically, the z196 machine has a maximum 96 cores versus z10's 64 core maximum, and each core runs 5.2GHz instead of z10's cores running at 4.7GHz. It is available in air-cooled and water-cooled models. The primary operating system that runs on this is called "z/OS", which when used with its integrated UNIX System Services subsystem, is fully UNIX-certified. The z196 server can also run z/VM, z/VSE, z/TPF and Linux on z, which is just Linux recompiled for the z/Architecture chip set. In my June 2008 post [Yes, Jon, there is a mainframe that can help replace 1500 servers], I mentioned the z10 mainframe had a top speed of nearly 30,000 MIPS (Million Instructions per Second). The new z196 machine can do 50,000 MIPS, a 60 percent increase!
The z196 runs a hypervisor called PR/SM that allows the box to be divided into dozens of logical partitions (LPAR), and the z/VM operating system can also act as a hypervisor running hundreds or thousands of guest OS images. Each core can be assigned a specialty engine "personality": GP for general processor, IFL for z/VM and Linux, zAAP for Java and XML processing, and zIIP for database, communications and remote disk mirroring. Like the z9 and z10, the z196 can attach to external disk and tape storage via ESCON, FICON or FCP protocols, and through NFS via 1GbE and 10GbE Ethernet.
IBM zEnterprise BladeCenter Extension (zBX)
There is a new frame called the zBX that basically holds two IBM BladeCenter chassis, each capable of 14 blades, so total of 28 blades per zBX frame. For now, only select blade servers are supported inside, but IBM plans to expand this to include more as testing continues. The POWER-based blades can run native AIX, IBM's other UNIX operating system, and the x86-based blades can run Linux-x86 workloads, for example. Each of these blade servers can run a single OS natively, or run a hypervisor to have multiple guest OS images. IBM plans to look into running other POWER and x86-based operating systems in the future.
If you are already familiar with IBM's BladeCenter, then you can skip this paragraph. Basically, you have a chassis that holds 14 blades connected to a "mid-plane". On the back of the chassis, you have hot-swappable modules that snap into the other side of the mid-plane. There are modules for FCP, FCoE and Ethernet connectivity, which allows blades to talk to each other, as well as external storage. BladeCenter Management modules serve as both the service processor as well as the keyboard, video and mouse Local Console Manager (LCM). All of the IBM storage options available to IBM BladeCenter apply to zBX as well.
Besides general purpose blades, IBM will offer "accelerator" blades that will offload work from the z196. For example, let's say an OLAP-style query is issued via SQL to DB2 on z/OS. In the process of parsing the complicated query, it creates a Materialized Query Table (MQT) to temporarily hold some data. This MQT contains just the columnar data required, which can then be transferred to a set of blade servers known as the Smart Analytics Optimizer (SAO), then processes the request and sends the results back. The Smart Analytics Optimizer comes in various sizes, from small (7 blades) to extra large (56 blades, 28 in each of two zBX frames). A 14-blade configuration can hold about 1TB of compressed DB2 data in memory for processing.
IBM zEnterprise Unified Resource Manager
You can have up to eight z196 machines and up to four zBX frames connected together into a monstrously large system. There are two internal networks. The Inter-ensemble data network (IEDN) is a 10GbE that connects all the OS images together, and can be further subdivided into separate virtual LANs (VLAN). The Inter-node management network (INMN) is a 1000 Mbps Base-T Ethernet that connects all the host servers together to be managed under a single pane of glass known as the Unified Resource Manager. It is based on IBM Systems Director.
By integrating service management, the Unified Resource Manager can handle Operations, Energy Management, Hypervisor Management, Virtual Server Lifecycle Management, Platform Performance Management, and Network Management, all from one place.
IBM Rational Developer for System z Unit Test (RDz)
But what about developers and testers, such as those Independent Software Vendors (ISV) that produce mainframe software. How can IBM make their lives easier?
Phil Smith on z/Journal provides a history of [IBM Mainframe Emulation]. Back in 2007, three emulation options were in use in various shops:
Open Mainframe, from Platform Solutions, Inc. (PSI)
FLEX-ES, from Fundamental Software, Inc.
Hercules, which is an open source package
None of these are viable options today. Nobody wanted to pay IBM for its Intellectual Property on the z/Architecture or license the use of the z/OS operating system. To fill the void, IBM put out an officially-supported emulation environment called IBM System z Professional Development Tool (zPDT) available to IBM employees, IBM Business Partners and ISVs that register through IBM Partnerworld. To help out developers and testers who work at clients that run mainframes, IBM now offers IBM Rational Developer for System z Unit Test, which is a modified version of zPDT that can run on a x86-based laptop or shared IBM System x server. Based on the open source [Eclipse IDE], the RDz emulates GP, IFL, zAAP and zIIP engines on a Linux-x86 base. A four-core x86 server can emulate a 3-engine mainframe.
With RDz, a developer can write code, compile and unit test all without consuming any mainframe MIPS. The interface is similar to Rational Application Developer (RAD), and so similar skills, tools and interfaces used to write Java, C/C++ and Fortran code can also be used for JCL, CICS, IMS, COBOL and PL/I on the mainframe. An IBM study ["Benchmarking IDE Efficiency"] found that developers using RDz were 30 percent more productive than using native z/OS ISPF. (I mention the use of RAD in my post [Three Things to do on the IBM Cloud]).
What does this all mean for the IT industry? First, the zEnterprise is perfectly positioned for [three-tier architecture] applications. A typical example could be a client-facing web-server on x86, talking to business logic running on POWER7, which in turn talks to database on z/OS in the z196 mainframe. Second, the zEnterprise is well-positioned for government agencies looking to modernize their operations and significantly reduce costs, corporations looking to consolidate data centers, and service providers looking to deploy public cloud offerings. Third, IBM storage is a great fit for the zEnterprise, with the IBM DS8000 series, XIV, SONAS and Information Archive accessible from both z196 and zBX servers.
Now an avid reader of my blog has brought this to my attention. Apparently,
EMC has been showing customers a presentation
[Accelerating Storage Transformation with VMAX and VPLEX] with false and misleading comparison claims between IBM DS8000, HDS VSP and EMC VMAX 40K disk system performance.
(FTC Disclosure: This would be a good time to remind my readers that I work for IBM and own IBM stock. I do not endorse any of the EMC or HDS products mentioned in this post, and have no financial affiliation or investments directly with either EMC nor HDS. I am basing my information solely on the presentation posted on the internet and other sources publicly available, and not on any misrepresentations from EMC speakers at the various conferences where these charts might have been shown.)
The problem with misinformation is that it is not always obvious. The EMC presentation is quite pretty and professional-looking. It is the typical slick, attention-getting, low-content, over-simplified marketing puffery you have come to expect from EMC. There are two slides in particular that I have issue with.
This first graphic implies that IBM and HDS are nearly tied in performance, but that EMC VMAX 40K has nearly triple that bandwidth. Overall the slide has very little detail. That makes it difficult to determine what exactly is being claimed and whether a fair comparison is being made.
The title claims that VMAX 40K is "#1 in High Bandwidth Apps". Only three disk systems are shown so the claim appears to be relative to only the three systems. The wording "High Bandwidth Apps" is confusing considering the cited numbers are for disk systems and no application is identified. By comparison, IBM SONAS can drive up to 105 GB/sec sequential bandwidth, nearly double what EMC claims for its VMAX 40K, so EMC is certainly not even close to #1.
Is the workload random or sequential? That is not easy to determine. The use of "GB/s" along with the large block size of 128KB implies the I/O workload is sequential, which is great for some workloads like high performance computing, technical computing and video broadcasts. Random workloads, on the other hand, are usually measured in I/Os per second (IOPS) with a block size ranging 4KB to 64KB. (I am assuming the 128K blocks refers to 128KB block size, and not reading the same block of cache 128,000 times.)
The slide states "Maximum Sustainable RRH Bandwidth 128K Blocks". The acronym "RRH" is not defined; but I suspect this refers to "random read hits". For random workloads, 100 percent random read hits from cache represents one corner of the infamous "four corners" test. Real-world workloads have a mix of reads and writes, and a mix of cache hits and cache misses. It is also unclear whether the hits are from standard data cache or from internal buffers in adapters (perhaps accessing the same blocks repeatedly) or something else. So is this really for a random workload, or a sequential workload?
(The term "Hitachi Math" was coined by an EMC blogger precisely to slam Hitachi Data Systems for their blatant use of four-corners results, claiming that spouting ridiculously large, but equally unrealistic, 100 percent random read hit results don't provide any useful information. I agree. There are much better industry-standard benchmarks available, such as SPC-1 for random workloads, SPC-2 for sequential workloads, and even benchmarks for specific applications, that represent real-world IT environments. To shame HDS for their use of four-corners results, only for EMC themselves to use similar figures in their own presentation is truly hypocritical of them!)
The IBM system is identified as "DS8000". DS8000 is a generic family name that applies to multiple generations of systems first introduced in 2004. The specific model is not identified, but that is critical information. Is this a first generation DS8100, or the latest DS8800, or something in between?
The slide says "Full System Configs", but that is not defined and configuration details are not identified. Configuration details, also critical information in assessing system performance capabilities, are not specified. If the EMC box costs seven times more than IBM or HDS, would you really buy it to get 3x more performance? Is the EMC packed with the maximum amount of SSD? Were there any SSD in the IBM or HDS boxes to match?
The source of the claimed IBM DS8000 performance numbers is not identified. Did they run their own tests? While I cannot tell, the VMAX may have been configured with 64 Fibre Channel 8Gbps host connections. In that case each channel is theoretically capable of supporting about 800 MB/s at 100% channel utilization. Multiplying 64 x 800MB/s = 51.2GB/s, so did EMC just do the performance comparison on the back of a napkin, assuming there are no other bottlenecks in the system? Even then, I would not round up 51.2 to 52!
Response times were not identified. For random I/Os, response time is a very important metric. It is possible that the Symmetrix was operating with some resources at 100% utilization to get the highest GB/s result, but that would likely make I/O response times unacceptable for real-world random I/O workloads.
IBM and HDS have both published Storage Performance Council [SPC] industry-standard performance benchmarks. EMC has not published any SPC benchmarks for VMAX systems. If EMC is interested in providing customers with audited, detailed performance information along with detailed configuration information, all based on benchmarks designed to represent real-world workloads, EMC can always publish SPC benchmark results as IBM and other vendors have done. In past blog fights, EMC resorts to the excuse that SPC isn't perfect, but can they really argue that vague and unrealistic claims cited in its presentation are better?
The second graphic is so absurd, you would think it came directly from Larry Ellison at an Oracle OpenWorld keynote session. EMC is comparing a configuration with VMAX 40K plus an EMC VFCache host-side flash memory cache card to a configuration with an IBM and HDS disk system without host-side flash memory cache also configured. The comparison is clearly apples-to-oranges. Other disk system configuration details are also omitted.
FAST VP is EMC's name for its sub-volume drive tiering feature, comparable to IBM Easy Tier and Hitachi's Dynamic Tiering. The graph implies that IBM and HDS can only achieve a modest increment improvement from their sub-volume tiering. I beg to differ. I have seen various cases where a small amount of SSD on IBM DS8000 series can drastically improve performance 200 to 400 percent.
The "DBClassify" shown on the graph is a tool run as part of an EMC professional services offering called Database Performance Tiering Assessment, makes recommendations for storing various database objects on different drive tiers based on object usage and importance. Do you really need to pay for professional services? With IBM Easy Tier, you just turn it on, and it works. No analysis required, no tools, no professional services, and no additional charge!
VFCache is an optional product from EMC that currently has no integration whatsoever with VMAX. A fair comparison would have included a host-side flash memory cache (from any vendor) when the IBM or HDS storage system was configured. Or leave it out altogether and just focus on the sub-volume tiering comparison.
Keep in mind that EMC's VFCache supports only selected x86-based hosts. IBM has published a [Statement of Direction] indicating that it will also offer this for Power systems running AIX and Linux host-side flash memory cache integrated with DS8000 Easy Tier.
I feel EMC's claims about IBM DS8000 performance are vague and misleading. EMC appears to lack the kind of technical marketing integrity that IBM strives to attain.
Since EMC is not able or willing to publish fair and meaningful performance comparisons, it is up to me to set the record straight and point out EMC's failings in this matter.
Reminder: It's not to late to register for my Webcast "Solving the Storage Capacity Crisis" on Tuesday, September 25. See my blog post [Upcoming events in September] to register!
Well, it's Tuesday again, and you know what that means? IBM Announcements!
This week, IBM announces the second generation of Storwize V5000 flash and disk storage systems. There are the V5000F All-flash configurations, as well as the V5000 that can support a variety of flash and spinning disk drives.
There are three models:
The V5010 has dual 2-core/2-thread processors and 16GB of cache. It supports thin provisioning, FlashCopy, Easy Tier, and remote mirroring. The base unit includes 1 GbE Ethernet ports for iSCSI host connectivity, with options to add 16GB Fibre Channel, 12Gb SAS, and 10GbE iSCSI/FCoE as well.
The 2U controllers and expansion enclosures can hold either 24 small 2.5-inch drives, or 12 larger 3.5-inch drives. A single control enclosure has two active/active IBM Spectrum Virtualize nodes, and can attach up to 10 expansion enclosures for a maximum of 264 drives.
The V5020 unit has dual 2-core/4-thread processors and up to 32GB of cache. It supports everything the V5010 does, plus encryption. The encryption is done via the Intel AES-NI instruction set to eliminate the need for special "self-encrypting drives" (SED) that other storage devices may require.
The V5030 has dual 6-core/4-thread processors and up to 64GB of cache. It supports everything the V5010 and V5020 do, plus Real-time Compression and external virtualization. The Real-time Compression can achieve up to 80 percent space savings, representing a 5:1 compression ratio.
Each control enclosure can attach to 20 expansion enclosures, which can support 504 internal drives per controller, and up to 1,008 with two controllers (four Spectrum Virtualize nodes) clustered together. This is in addition to the drives in external storage systems virtualized.
Last week, I presented IBM's strategic initiative, the IBM Information Infrastructure, which is part of IBM's New Enterprise Data Center vision. This week, I will try to get around to talking about some of theproducts that support those solutions.
I was going to set the record straight on a variety of misunderstandings, rumors or speculations, but I think most have been taken care of already. IBM blogger BarryW covered the fact that SVC now supports XIV storage systems, in his post[SVC and XIV],and addressed some of the FUD already. Here was my list:
Now that IBM has an IBM-branded model of XIV, IBM will discontinue (insert another product here)
I had seen speculation that XIV meant the demise of the N series, the DS8000 or IBM's partnership with LSI.However, the launch reminded people that IBM announced a new release of DS8000 features, new models of N series N6000,and the new DS5000 disk, so that squashes those rumors.
IBM XIV is a (insert tier level here) product
While there seems to be no industry-standard or agreement for what a tier-1, tier-2 or tier-3 disk system is, there seemed to be a lot of argument over what pigeon-hole category to put IBM XIV in. No question many people want tier-1 performance and functionality at tier-2 prices, and perhaps IBM XIV is a good step at giving them this. In some circles, tier-1 means support for System z mainframes. The XIV does not have traditional z/OS CKD volume support, but Linux on System z partitions or guests can attach to XIV via SAN Volume Controller (SVC), or through NFS protocol as part of the Scale-Out File Services (SoFS) implementation.
Whenever any radicalgame-changing technology comes along, competitors with last century's products and architectures want to frame the discussion that it is just yet another storage system. IBM plans to update its Disk Magic and otherplanning/modeling tools to help people determine which workloads would be a good fit with XIV.
IBM XIV lacks (insert missing feature here) in the current release
I am glad to see that the accusations that XIV had unprotected, unmirrored cache were retracted. XIV mirrors all writes in the cache of two separate modules, with ECC protection. XIV allows concurrent code loadfor bug fixes to the software. XIV offers many of the features that people enjoy in other disksystems, such as thin provisioning, writeable snapshots, remote disk mirroring, and so on.IBM XIV can be part of a bigger solution, either through SVC, SoFS or GMAS that provide thebusiness value customers are looking for.
IBM XIV uses (insert block mirroring here) and is not as efficient for capacity utilization
It is interesting that this came from a competitor that still recommends RAID-1 or RAID-10 for itsCLARiiON and DMX products.On the IBM XIV, each 1MB chunk is written on two different disks in different modules. When disks wereexpensive, how much usable space for a given set of HDD was worthy of argument. Today, we sell you abig black box, with 79TB usable, for (insert dollar figure here). For those who feel 79TB istoo big to swallow all at once, IBM offers "capacity on demand" pricing, where you can pay initially for as littleas 22TB, but get all the performance, usability, functionality and advanced availability of the full box.
IBM XIV consumes (insert number of Watts here) of energy
For every disk system, a portion of the energy is consumed by the number of hard disk drives (HDD) andthe remainder to UPS, power conversion, processors and cache memory consumption. Again, the XIV is a bigblack box, and you can compare the 8.4 KW of this high-performance, low-cost storage one-frame system with thewattage consumed by competitive two-frame (sometimes called two-bay) systems, if you are willing to take some trade-offs. To getcomparable performance and hot-spot avoidance, competitors may need to over-provision or use faster, energy-consuming FC drives, and offer additional software to monitor and re-balance workloads across RAID ranks.To get comparable availability, competitors may need to drop from RAID-5 down to either RAID-1 or RAID-6.To get comparable usability, competitors may need more storage infrastructure management software to hide theinherent complexity of their multi-RAID design.
Of course, if energy consumption is a major concern for you, XIV can be part of IBM's many blended disk-and-tapesolutions. When it comes to being green, you can't get any greener storage than tape! Blended disk-and-tapesolutions help get the best of both worlds.
Well, I am glad I could help set the record straight. Let me know what other products people you would like me to focus on next.