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Tony Pearson is a Master Inventor, Senior IT Architect and Event Content Manager for [IBM Systems for IBM Systems Technical University] events. With over 30 years with IBM Systems, Tony is frequent traveler, speaking to clients at events throughout the world.
Lloyd Dean is an IBM Senior Certified Executive IT Architect in Infrastructure Architecture. Lloyd has held numerous senior technical roles at IBM during his 19 plus years at IBM. Lloyd most recently has been leading efforts across the Communication/CSI Market as a senior Storage Solution Architect/CTS covering the Kansas City territory. In prior years Lloyd supported the industry accounts as a Storage Solution architect and prior to that as a Storage Software Solutions specialist during his time in the ATS organization.
Lloyd currently supports North America storage sales teams in his Storage Software Solution Architecture SME role in the Washington Systems Center team. His current focus is with IBM Cloud Private and he will be delivering and supporting sessions at Think2019, and Storage Technical University on the Value of IBM storage in this high value IBM solution a part of the IBM Cloud strategy. Lloyd maintains a Subject Matter Expert status across the IBM Spectrum Storage Software solutions. You can follow Lloyd on Twitter @ldean0558 and LinkedIn Lloyd Dean.
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“In times of universal deceit, telling the truth will be a revolutionary act.”
-- George Orwell
Well, it has been over two years since I first covered IBM's acquisition of the XIV company. Amazingly, I still see a lot of misperceptions out in the blogosphere, especially those regarding double drive failures for the XIV storage system. Despite various attempts to [explain XIV resiliency] and to [dispel the rumors], there are still competitors making stuff up, putting fear, uncertainty and doubt into the minds of prospective XIV clients.
Clients love the IBM XIV storage system! In this economy, companies are not stupid. Before buying any enterprise-class disk system, they ask the tough questions, run evaluation tests, and all the other due diligence often referred to as "kicking the tires". Here is what some IBM clients have said about their XIV systems:
“3-5 minutes vs. 8-10 hours rebuild time...”
-- satisfied XIV client
“...we tested an entire module failure - all data is re-distributed in under 6 hours...only 3-5% performance degradation during rebuild...”
-- excited XIV client
“Not only did XIV meet our expectations, it greatly exceeded them...”
In this blog post, I hope to set the record straight. It is not my intent to embarrass anyone in particular, so instead will focus on a fact-based approach.
Fact: IBM has sold THOUSANDS of XIV systems
XIV is "proven" technology with thousands of XIV systems in company data centers. And by systems, I mean full disk systems with 6 to 15 modules in a single rack, twelve drives per module. That equates to hundreds of thousands of disk drives in production TODAY, comparable to the number of disk drives studied by [Google], and [Carnegie Mellon University] that I discussed in my blog post [Fleet Cars and Skin Cells].
Fact: To date, no customer has lost data as a result of a Double Drive Failure on XIV storage system
This has always been true, both when XIV was a stand-alone company and since the IBM acquisition two years ago. When examining the resilience of an array to any single or multiple component failures, it's important to understand the architecture and the design of the system and not assume all systems are alike. At it's core, XIV is a grid-based storage system. IBM XIV does not use traditional RAID-5 or RAID-10 method, but instead data is distributed across loosely connected data modules which act as independent building blocks. XIV divides each LUN into 1MB "chunks", and stores two copies of each chunk on separate drives in separate modules. We call this "RAID-X".
Spreading all the data across many drives is not unique to XIV. Many disk systems, including EMC CLARiiON-based V-Max, HP EVA, and Hitachi Data Systems (HDS) USP-V, allow customers to get XIV-like performance by spreading LUNs across multiple RAID ranks. This is known in the industry as "wide-striping". Some vendors use the terms "metavolumes" or "extent pools" to refer to their implementations of wide-striping. Clients have coined their own phrases, such as "stripes across stripes", "plaid stripes", or "RAID 500". It is highly unlikely that an XIV will experience a double drive failure that ultimately requires recovery of files or LUNs, and is substantially less vulnerable to data loss than an EVA, USP-V or V-Max configured in RAID-5. Fellow blogger Keith Stevenson (IBM) compared XIV's RAID-X design to other forms of RAID in his post [RAID in the 21st Centure].
Fact: IBM XIV is designed to minimize the likelihood and impact of a double drive failure
The independent failure of two drives is a rare occurrence. More data has been lost from hash collisions on EMC Centera than from double drive failures on XIV, and hash collisions are also very rare. While the published worst-case time to re-protect from a 1TB drive failure for a fully-configured XIV is 30 minutes, field experience shows XIV regaining full redundancy on average in 12 minutes. That is 40 times less likely than a typical 8-10 hour window for a RAID-5 configuration.
A lot of bad things can happen in those 8-10 hours of traditional RAID rebuild. Performance can be seriously degraded. Other components may be affected, as they share cache, connected to the same backplane or bus, or co-dependent in some other manner. An engineer supporting the customer onsite during a RAID-5 rebuild might pull the wrong drive, thereby causing a double drive failure they were hoping to avoid. Having IBM XIV rebuild in only a few minutes addresses this "human factor".
In his post [XIV drive management], fellow blogger Jim Kelly (IBM) covers a variety of reasons why storage admins feel double drive failures are more than just random chance. XIV avoids load stress normally associated with traditional RAID rebuild by evenly spreading out the workload across all drives. This is known in the industry as "wear-leveling". When the first drive fails, the recovery is spread across the remaining 179 drives, so that each drive only processes about 1 percent of the data. The [Ultrastar A7K1000] 1TB SATA disk drives that IBM uses from HGST have specified 1.2 million hours mean-time-between-failures [MTBF] would average about one drive failing every nine months in a 180-drive XIV system. However, field experience shows that an XIV system will experience, on average, one drive failure per 13 months, comparable to what companies experience with more robust Fibre Channel drives. That's innovative XIV wear-leveling at work!
Fact: In the highly unlikely event that a DDF were to occur, you will have full read/write access to nearly all of your data on the XIV, all but a few GB.
Even though it has NEVER happened in the field, some clients and prospects are curious what a double drive failure on an XIV would look like. First, a critical alert message would be sent to both the client and IBM, and a "union list" is generated, identifying all the chunks in common. The worst case on a 15-module XIV fully loaded with 79TB data is approximately 9000 chunks, or 9GB of data. The remaining 78.991 TB of unaffected data are fully accessible for read or write. Any I/O requests for the chunks in the "union list" will have no response yet, so there is no way for host applications to access outdated information or cause any corruption.
(One blogger compared losing data on the XIV to drilling a hole through the phone book. Mathematically, the drill bit would be only 1/16th of an inch, or 1.60 millimeters for you folks outside the USA. Enough to knock out perhaps one character from a name or phone number on each page. If you have ever seen an actor in the movies look up a phone number in a telephone booth then yank out a page from the phone book, the XIV equivalent would be cutting out 1/8th of a page from an 1100 page phone book. In both cases, all of the rest of the unaffected information is full accessible, and it is easy to identify which information is missing.)
If the second drive failed several minutes after the first drive, the process for full redundancy is already well under way. This means the union list is considerably shorter or completely empty, and substantially fewer chunks are impacted. Contrast this with RAID-5, where being 99 percent complete on the rebuild when the second drive fails is just as catastrophic as having both drives fail simultaneously.
Fact: After a DDF event, the files on these few GB can be identified for recovery.
Once IBM receives notification of a critical event, an IBM engineer immediately connects to the XIV using remote service support method. There is no need to send someone physically onsite, the repair actions can be done remotely. The IBM engineer has tools from HGST to recover, in most cases, all of the data.
Any "union" chunk that the HGST tools are unable to recover will be set to "media error" mode. The IBM engineer can provide the client a list of the XIV LUNs and LBAs that are on the "media error" list. From this list, the client can determine which hosts these LUNs are attached to, and run file scan utility to the file systems that these LUNs represent. Files that get a media error during this scan will be listed as needing recovery. A chunk could contain several small files, or the chunk could be just part of a large file. To minimize time, the scans and recoveries can all be prioritized and performed in parallel across host systems zoned to these LUNs.
As with any file or volume recovery, keep in mind that these might be part of a larger consistency group, and that your recovery procedures should make sense for the applications involved. In any case, you are probably going to be up-and-running in less time with XIV than recovery from a RAID-5 double failure would take, and certainly nowhere near "beyond repair" that other vendors might have you believe.
Fact: This does not mean you can eliminate all Disaster Recovery planning!
To put this in perspective, you are more likely to lose XIV data from an earthquake, hurricane, fire or flood than from a double drive failure. As with any unlikely disaster, it is best to have a disaster recovery plan than to hope it never happens. All disk systems that sit on a single datacenter floor are vulnerable to such disasters.
For mission-critical applications, IBM recommends using disk mirroring capability. IBM XIV storage system offers synchronous and asynchronous mirroring natively, both included at no additional charge.
Are you tired of hearing about Cloud Computing without having any hands-on experience? Here's your chance. IBM has recently launched its IBM Development and Test Cloud beta. This gives you a "sandbox" to play in. Here's a few steps to get started:
Generate a "key pair". There are two keys. A "public" key that will reside in the cloud, and a "private" key that you download to your personal computer. Don't lose this key.
Request an IP address. This step is optional, but I went ahead and got a static IP, so I don't have to type in long hostnames like "vm353.developer.ihost.com".
Request storage space. Again, this step is optional, but you can request a 50GB, 100GB and 200GB LUN. I picked a 200GB LUN. Note that each instance comes with some 10 to 30GB storage already. The advantage to a storage LUN is that it is persistent, and you can mount it to different instances.
Start an "instance". An "instance" is a virtual machine, pre-installed with whatever software you chose from the "asset catalog". These are Linux images running under Red Hat Enterprise Virtualization (RHEV) which is based on Linux's kernel virtual machine (KVM). When you start an instance, you get to decide its size (small, medium, or large), whether to use your static IP address, and where to mount your storage LUN. On the examples below, I had each instance with a static IP and mounted the storage LUN to /media/storage subdirectory. The process takes a few minutes.
So, now that you are ready to go, what instance should you pick from the catalog? Here are three examples to get you started:
IBM WebSphere sMASH Application Builder
Base OS server to run LAMP stack
Next, I decided to try out one of the base OS images. There are a lot of books on Linux, Apache, MySQL and PHP (LAMP) which represents nearly 70 percent of the web sites on the internet. This instance let's you install all the software from scratch. Between Red Hat and Novell SUSE distributions of Linux, Red Hat is focused on being the Hypervisor of choice, and SUSE is focusing on being the Guest OS of choice. Most of the images on the "asset catalog" are based on SLES 10 SP2. However, there was a base OS image of Red Hat Enterprise Linux (RHEL) 5.4, so I chose that.
To install software, you either have to find the appropriate RPM package, or download a tarball and compile from source. To try both methods out, I downloaded tarballs of Apache Web Server and PHP, and got the RPM packages for MySQL. If you just want to learn SQL, there are instances on the asset catalog with DB2 and DB2 Express-C already pre-installed. However, if you are already an expert in MySQL, or are following a tutorial or examples based on MySQL from a classroom textbook, or just want a development and test environment that matches what your company uses in production, then by all means install MySQL.
This is where my SSH client comes in handy. I am able to login to my instance and use "wget" to fetch the appropriate files. An alternative is to use "SCP" (also part of PuTTY) to do a secure copy from your personal computer up to the instance. You will need to do everything via command line interface, including editing files, so I found this [VI cheat sheet] useful. I copied all of the tarballs and RPMs on my storage LUN ( /media/storage ) so as not to have to download them again.
Compiling and configuring them is a different matter. By default, you login as an end user, "idcuser" (which stands for IBM Developer Cloud user). However, sometimes you need "root" level access. Use "sudo bash" to get into root level mode, and this allows you to put the files where they need to be. If you haven't done a configure/make/make install in awhile, here's your chance to relive those "glory days".
In the end, I was able to confirm that Apache, MySQL and PHP were all running correctly. I wrote a simple index.php that invoked phpinfo() to show all the settings were set correctly. I rebooted the instance to ensure that all of the services started at boot time.
Rational Application Developer over VDI
This last example, I started an instance pre-installed with Rational Application Developer (RAD), which is a full Integrated Development Environment (IDE) for Java and J2EE applications. I used the "NX Client" to launch a virtual desktop image (VDI) which in this case was Gnome on SLES 10 SP2. You might want to increase the screen resolution on your personal computer so that the VDI does not take up the entire screen.
From this VDI, you can launch any of the programs, just as if it were your own personal computer. Launch RAD, and you get the familiar environment. I created a short Java program and launched it on the internal WebSphere Application Server test image to confirm it was working correctly.
If you are thinking, "This is too good to be true!" there is a small catch. The instances are only up and running for 7 days. After that, they go away, and you have to start up another one. This includes any files you had on the local disk drive. You have a few options to save your work:
Copy the files you want to save to your storage LUN. This storage LUN appears persistent, and continues to exist after the instance goes away.
Take an "image" of your "instance", a function provided in the IBM Developer and Test Cloud. If you start a project Monday morning, work on it all week, then on Friday afternoon, take an "image". This will shutdown your instance, and backup all of the files to your own personal "asset catalog" so that the next time you request an instance, you can chose that "image" as the starting point.
Another option is to request an "extension" which gives you another 7 days for that instance. You can request up to five unique instances running at the same time, so if you wanted to develop and test a multi-host application, perhaps one host that acts as the front-end web server, another host that does some kind of processing, and a third host that manages the database, this is all possible. As far as I can tell, you can do all the above from either a Windows, Mac or Linux personal computer.
Getting hands-on access to Cloud Computing really helps to understand this technology!
Last week, I presented "An Introduction to Cloud Computing" for two hours to the local Institute of Management Accountants [IMA] for their Continuing Professional Education [CPE]. Since I present IBM's leadership in Cloud Storage offerings, I have had to become an expert in Cloud Computing overall. The audience was a mix of bookkeepers, accountants, auditors, comptrollers, CPAs, and accounting teachers.
Here is a sample of the questions I took during and after my presentation:
If I need to shut down host machine, I lose all my virtual machines as well?
No, it is possible to seemlessly move virtual machines from one host to another. If you need to shut down a host machine, move all the VMs to other hosts, then you can shut down the empty host without impacting business.
Does the SaaS provider have to build their own app, can they not buy an app and then rent it out?
Yes, but they won't have competitive differentiation, and the software development they buy from will want a big cut of the action. SaaS developers that build their own applications can keep more of the profits for themselves.
How do backups work in cloud computing? Do I have to contact someone at the cloud computing company to find the backup tape?
Large datacenters often keep the most recent backups on disk, and older versions on tape in automated tape libraries that can fetch your backup in less than 2 minutes. Because of this, there is no need to talk to anyone, you can schedule or invoke your own backups, and often perform the recovery yourself using self-service tools.
Last month, my sister tried to rent a car during the week the Tucson Gem Show, but they were out of cars she wanted to drive. Could this happen with Cloud Computing?
Not likely. With rental cars, the cars have to be physically in Tucson to rent them. Rental companies could have brought cars down from Phoenix to satisfy demand. With Cloud Computing, it is all accessible over the global network, you are not limited to the cloud providers nearest you.
Is there a reason why Amazon Web Services (AWS) charges more for a Windows image than a Linux image?
Yes, Amazon and Microsoft have a patent cross-licensing agreement where Amazon pays Microsoft for the priveledge of offering Windows-based images on their EC2 cloud infrastructure. It just makes business sense to pass those costs onto the consumer. Linux is a free open source operating system, and is often the better choice.
So if we rent a machine from Amazon, they send it to my accounting office? What exactly am I getting for 12 cents per hour?
No. The computer remains in their datacenter. You get a virtual machine that runs 1.2Ghz Intel processor, with 1700MB of RAM, and 160GB of hard disk space, with Windows operating system running on it, comparable to a machine you can get at the local BestBuy, but instead of it running in the next room, it is running in a datacenter somewhere else in the United States with electricity and air conditioning.
You access it remotely from your desktop or laptop PC.
Why would I ever rent more than one computer?
It depends on your workload. For example, Derek Gottfrid at the New York Times needed to convert 11 million articles from TIFF format to PDF format so that he could put them up on the web. This would have taken him months using a single computer, so he rented 100 computers and got the entire stack converted in 24 hours, for a cost of about $240. See the articles [Self-Service, Prorated, Super Computing] and [TimesMachine] for details.
What about throughput? Won't I need to run cables from my accounting office to this cloud computing data center?
You will need connectivity, most likely from connections provided by your local telephone or cable company, or through the Internet. Certainly, there can be cases where direct privately-owned fiber optic cables, known as "dark fiber", can directly connect consumers to local Cloud service providers, for added security.
What about medical records? Will Cloud Computing help the Healthcare industry?
Yes, hospitals are finding that digitizing their records greatly reduces costs. IBM offers the Grid Medical Archive Solution [GMAS] as a private cloud storage solution to store X-ray images and other electronic medical records on disk and tape, and these records can be accessed from multiple hospitals and clinics, wherever the doctor or patient happens to be.
The advantage of personal computers was individualization, I could put on my own choices of software, and customize my own settings, won't we lose this with Cloud Computing?
Yes, customized software and settings cost companies millions of dollars with help desk calls. Cloud Computing attempts to provide some standardization, reducing the amount of effort to support IT operations.
Won't putting all the computers into a big datacenter make them more vulnerable to hackers?
Security is a well-known concern, but this is being addressed with encryption, access control lists, multi-tenancy isolation, and VPN connections.
My daughter has a BlackBerry or iPod or something, and when we mentioned that someone in Phoenix wore a monkey suit to avoid photo-radar speed cameras, she was able to pull up a picture on her little hand-held thing, is this the future?
Yes, mobile phones and other hand-held devices now have internet access to take advantage of Cloud Computing services. People will be able to access the information they need from wherever they happen to be. (You can see the picture here: [Man Dons Mask for Speed-Camera Photos])
IBM offers a variety of Cloud Computing services, as well as customized solutions and integrated systems that can be deployed on-premises behind your corporate firewall. To learn more, go to [ibm.com/cloud].
The second speaker was local celebrity Dan Ryan presenting the financials for the upcoming [Rosemont Copper] mining operations. Copper is needed for emerging markets, such as hybrid vehicles and wind turbines. Copper is a major industry in Arizona.
The marketshare data for external disk systems has been released by IDC for 4Q09. Overall, the market dropped 0.7 percent, comparing 4Q09 versus 4Q08. While EMC was quick to remind everyone that they were able to [maintain their #1 position] in the storage subset of "external disk systems", with the same 23.7 percent marketshare they had back in 4Q08 and revenues that were essentially flat, the real story concerns the shifts in the marketplace for the other major players. IBM grew revenue 9 percent, putting it nearly 5 points of marketshare ahead of HP. HP revenues dropped 7 percent, moving it further behind. Not mentioned in the [IBM Press Release] were NetApp and Dell, neck and neck for fourth place, with NetApp gaining 16.8 percent in revenues, while Dell dropped 13.5 percent. Both NetApp and Dell now have about 8 percent marketshare each. These top five storage vendors represent nearly 70 percent of the marketshare.
Given that HP is IBM's number one competitor, not just in storage but all things IT, this was a major win. Bob Evans from InformationWeek interviews my fifth-line manager, IBM executive Rod Adkins [IBM Claims Hardware Supremacy] where he shares his views and opinions about HP, Oracle-Sun, Cisco and Dell.
I'll add my two cents on what's going on:
Shift in Servers causes Shift in Storage
Hundreds of customers are moving away from HP and Sun over to IBM servers, and with it, are chosing IBM's storage offerings as well. IBM's rock-solid strategy (which I outlined in my post [Foundations and Flavorings]) has helped explain the different products and how they are positioned. HP's use of Itanium processors, and Sun's aging SPARC line, are both reasons enough to switch to IBM's lastest POWER7 processors, running AIX, IBM i (formerly i5/OS) and Linux operating systems.
Thunder in the Clouds
Some analysts predict that by 2013, one out of five companies won't even have their own IT assets. IBM supports all flavors of private, public and hybrid cloud computing models. IBM has its own strong set of offerings, is also the number one reseller of VMware, and has cloud partnerships with both Google and Amazon. HP and Microsoft have recently formed an alliance, but they have different takes on cloud computing. HP wants to be the "infrastructure" company, but Microsoft wants to focus on its ["three screens and a public cloud"] strategy. Microsoft has decided not to make its Azure Cloud operating system available for private cloud deployments. By contrast, IBM can start you with a private cloud, then help you transition to a hybrid cloud, and finally to a public cloud.
In the latest eX5 announcement, IBM's x86-based servers can run 78 percent more virtual machines per VMware license dollar. This will give IBM an advantage as HP shifts from Itanium to an all x86-based server line.
Network Attached Storage
There seems to be a shift away from FC and iSCSI towards NAS and FCoE storage networking protocols. This bodes bad for HP's acquisition of LeftHand, and Dell's acquisition of EqualLogic. IBM's SONAS for large deployments, and N series for smaller deployments, will compete nicely against HP's StorageWorks X9000 system.
Storage on Paper no longer Eco-friendly
HP beats IBM when you include consumer products like printers, which some might consider "Storage on Paper". At IBM, we often joke that 96 percent of HP's profits come from over-priced ink cartridges. With the latest focus on the environment, people are printing less. I have been printing less myself, setting my default printer to generate a PDF file instead. There are several tools available for this, including [CutePDF] and [BullZip]. As IBM employees switch from Microsoft Office to IBM's [Lotus Symphony], it has built-in "export-to-PDF" capability as well. People are also going to their local OfficeMax or CartridgeWorld to get their cartridges refilled, rather than purchase new ones. That has to be hurting HP's bottom line.
Don't Forget About Storage Management
The leading storage management suites today are IBM's Tivoli Storage Productivity Center and EMC's Control Center. HP's Storage Essentials doesn't quite beat either of these, and management software is growing in importance to more and more customers.
This week I got a comment on my blog post [IBM Announces another SSD Disk offering!]. The exchange involved Solid State Disk storage inside the BladeCenter and System x server line. Sandeep offered his amazing performance results, but we have no way to get in contact with him. So, for those interested, I have posted on SlideShare.net a quick five-chart presentation on recent tests with various SSD offerings on the eX5 product line here: