Tony Pearson is a Master Inventor and Senior IT Architect for the IBM Storage product line at the
IBM Systems Client Experience 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 )
My books are available on Lulu.com! Order your copies today!
Safe Harbor Statement: The information on IBM products is intended to outline IBM's general product direction and it should not be relied on in making a purchasing decision. The information on the new products is for informational purposes only and may not be incorporated into any contract. The information on IBM products is not a commitment, promise, or legal obligation to deliver any material, code, or functionality. The development, release, and timing of any features or functionality described for IBM products remains at IBM's sole discretion.
Tony Pearson is a an active participant in local, regional, and industry-specific interests, and does not receive any special payments to mention them on this blog.
Tony Pearson receives part of the revenue proceeds from sales of books he has authored listed in the side panel.
Tony Pearson is not a medical doctor, and this blog does not reference any IBM product or service that is intended for use in the diagnosis, treatment, cure, prevention or monitoring of a disease or medical condition, unless otherwise specified on individual posts.
I saw this as an opportunity to promote the new IBM Tivoli Storage Manager v6.1 which offers a variety of new scalability features, and continues to provide excellent economies of scale for large deployments, in my post [IBM has scalable backup solutions].
"So does TSM scale? Sure! Just add more servers. But this is not an economy of scale. Nothing gets less expensive as the capacity grows. You get a more or less linear growth of costs that is directly correlated to the growth of primary storage capacity. (Technically, it costs will jump at regular and predictable intervals, by regular and predictable and equal amounts, as you add TSM servers to the infrastructure--but on average it is a direct linear growth. Assuming you are right sized right now, if you were to double your primary storage capacity, you would double the size of the TSM infrastructure, and double your associated costs.)"
I talked about inaccurate vendor FUD in my post [The murals in restaurants], and recently, I saw StorageBod's piece, [FUDdy Waters]. So what would "economies of scale" look like? Using Scott's own words:
Without Economies of Scale
"If it costs you $5 to backup a given amount of data, it probably costs you $50 to back up 10 times that amount of data, and $500 to back up 100 times that amount of data."
With Economies of Scalee
"If anybody can figure out how to get costs down to $40 for 10 times the amount of data, and $300 for 100 times the amount of data, they will have an irrefutable advantage over anybody that has not been able to leverage economies of scale."
So, let's do some simple examples. I'll focus on a backup solution just for employee workstations, each employee has 100GB of personal data to backup on their laptop or PC. We'll look at a one-person company, a ten-person company, and a hundred-person company.
Case 1: The one-person company
Here the sole owner needs a backup solution. Here are all the steps she might perform:
Spend hours of time evaluating different backup products available, and make sure her operating system, file system and applications are supported
Spend hours shopping for external media, this could be an external USB disk drive, optical DVD drive, or tape drive, and confirm it is supported by the selected backup software.
Purchase the backup software, external drive, and if optical or tape, blank media cartridges.
Spend time learning the product, purchase "Backup for Dummies" or similar book, and/or taking a training class.
Install and configure the software
Operate the software, or set it up to run automatically, and take the media offsite at the end of the day, and back each morning
Case 2: The ten-person company
I guess if each of the ten employees went off and performed all of the same steps as above, there would be no economies of scale.
Fortunately, co-workers are amazingly efficient in avoiding unnecessary work.
Rather than have all ten people evaluate backup solutions, have one person do it. If everyone runs the same or similar operating system, file systems and applications, this can be done about the same as the one-person case.
Ditto on the storage media. Why should 10 people go off and evaluate their own storage media. One person can do it for all ten people in about the same time as it takes for one person.
Purchasing the software and hardware. Ok, here is where some costs may be linear, depending on your choices. Some software vendors give bulk discounts, so purchasing 10 seats of the same software could be less than 10 times the cost of one license. As for storage hardware, it might be possible to share drives and even media. Perhaps one or two storage systems can be shared by the entire team.
For a lot of backup software, most of the work is in the initial set up, then it runs automatically afterwards. That is the case for TSM. You create a "dsm.opt" file, and it can list all of the include/exclude files and other rules and policies. Once the first person sets this up, they share it with their co-workers.
Hopefully, if storage hardware was consolidated, such that you have fewer drives than people, you can probably have fewer people responsible for operations. For example, let's have the first five employees sharing one drive managed by Joe, and the second five employees sharing a second drive managed by Sally. Only two people need to spend time taking media offsite, bringing it back and so on.
Case 3: The hundred-person company
Again, it is possible that a hundred-person company consists of 10 departments of 10 people each, and they all follow the above approach independently, resulting in no economies of scale. But again, that is not likely.
Here one or a few people can invest time to evaluate backup solutions. Certainly far less than 100 times the effort for a one-person company.
Same with storage media. With 100 employees, you can now invest in a tape library with robotic automation.
Purchase of software and hardware. Again, discounts will probably apply for large deployments. Purchasing 1 tape library for all one hundred people is less than 10 times the cost and effort of 10 departments all making independent purchases.
With a hundred employees, you may have some differences in operating system, file systems and applications. Still, this might mean two to five versions of dsm.opt, and not 10 or 100 independent configurations.
Operations is where the big savings happen. TSM has "progressive incremental backup" so it only backs up changed data. Other backup schemes involve taking period full backups which tie up the network and consume a lot of back end resources. In head-to-head comparisons between IBM Tivoli Storage Manager and Symantec's NetBackup, IBM TSM was shown to use significantly less network LAN bandwidth, less disk storage capacity, and fewer tape cartridges than NetBackup.
The savings are even greater with data deduplication. Either using hardware, like IBM TS76750 ProtecTIER data deduplication solution, or software like the data deduplication capability built-in with IBM TSM v6.1, you can take advantage of the fact that 100 employees might have a lot of common data between them.
So, I have demonstrated how savings through economies of scale are achieved using IBM Tivoli Storage Manager. Adding one more person in each case is cheaper than the first person. The situation is not linear as Scott suggests. But what about larger deployments? IBM TS3500 Tape Library can hold one PB of data in only 10 square feet of data center floorspace. The IBM TS7650G gateway can manage up to 1 PB of disk, holding as much as 25 PB of backup copies. IT Analysts Tony Palmer, Brian Garrett and Lauren Whitehouse from Enterprise Strategy Group tried IBM TSM v6.1 out for themselves and wrote up a ["Lab Validation"] report. Here is an excerpt:
"Backup/recovery software that embeds data reduction technology can address all three of these factors handily. IBM TSM 6.1 now has native deduplication capabilities built into its Extended Edition (EE) as a no-cost option. After data is written to the primary disk pool, a deduplication operation can be scheduled to eliminate redundancy at the sub-file level. Data deduplication, as its name implies, identifies and eliminates redundant data.
TSM 6.1 also includes features that optimize TSM scalability and manageability to meet increasingly demanding service levels resulting from relentless data growth. The move from a proprietary back-end database to IBM DB2 improves scalability, availability, and performance without adding complexity; the DB2 database is automatically maintained and managed by TSM. IBM upgraded the monitoring and reporting capabilities to near real-time and completely redesigned the dashboard that provides visibility into the system. TSM and TSM EE include these enhanced monitoring and reporting capabilities at no cost."
The majority of Fortune 1000 customers use IBM Tivoli Storage Manager, and it is the backup software that IBM uses itself in its own huge data centers, including the cloud computing facilities. In combination with IBM Tivoli FastBack for remote office/branch office (ROBO) situations, and complemented with point-in-time and disk mirroring hardware capabilities such as IBM FlashCopy, Metro Mirror, and Global Mirror, IBM Tivoli Storage Manager can be an effective, scalable part of a complete Unified Recovery Management solution.
Well, it's Tuesday again, but this time, today we had our third big storage launch of 2009! A lot got announced today as part of IBM's big "Dynamic Infrastructure" marketing campaign. I will just focus on the
disk-related announcements today:
IBM System Storage DS8700
IBM adds a new model to its DS8000 series with the
[IBM System Storage DS8700]. Earlier this month, fellow blogger and arch-nemesis Barry Burke from EMC posted [R.I.P DS8300] on this mistaken assumption that the new DS8700 meant that DS8300 was going away, or that anyone who bought a DS8300 recently would be out of luck. Obviously, I could not respond until today's announcement, as the last thing I want to do is lose my job disclosing confidential information. BarryB is wrong on both counts:
IBM will continue to sell the DS8100 and DS8300, in addition to the new DS8700.
Clients can upgrade their existing DS8100 or DS8300 systems to DS8700.
BarryB's latest post [What's In a Name - DS8700] is fair game, given all the fun and ridicule everyone had at his expense over EMC's "V-Max" name.
So the DS8700 is new hardware with only 4 percent new software. On the hardware side, it uses faster POWER6 processors instead of POWER5+, has faster PCI-e buses instead of the RIO-G loops, and faster four-port device adapters (DAs) for added bandwidth between cache and drives. The DS8700 can be ordered as a single-frame dual 2-way that supports up to 128 drives and 128GB of cache, or as a dual 4-way, consisting of one primary frame, and up to four expansion frames, with up to 384GB of cache and 1024 drives.
Not mentioned explicitly in the announcements were the things the DS8700 does not support:
ESCON attachment - Now that FICON is well-established for the mainframe market, there is no need to support the slower, bulkier ESCON options. This greatly reduced testing effort. The 2-way DS8700 can support up to 16 four-port FICON/FCP host adapters, and the 4-way can support up to 32 host adapters, for a maximum of 128 ports. The FICON/FCP host adapter ports can auto-negotiate between 4Gbps, 2Gbps and 1Gbps as needed.
LPAR mode - When IBM and HDS introduced LPAR mode back in 2004, it sounded like a great idea the engineers came up with. Most other major vendors followed our lead to offer similar "partitioning". However, it turned out to be what we call in the storage biz a "selling apple" not a "buying apple". In other words, something the salesman can offer as a differentiating feature, but that few clients actually use. It turned out that supporting both LPAR and non-LPAR modes merely doubled the testing effort, so IBM got rid of it for the DS8700.
Update: I have been reminded that both IBM and HDS delivered LPAR mode within a month of each other back in 2004, so it was wrong for me to imply that HDS followed IBM's lead when obviously development happened in both companies for the most part concurrently prior to that. EMC was late to the "partition" party, but who's keeping track?
Initial performance tests show up to 50 percent improvement for random workloads, and up to 150 percent improvement for sequential workloads, and up to 60 percent improvement in background data movement for FlashCopy functions. The results varied slightly between Fixed Block (FB) LUNs and Count-Key-Data (CKD) volumes, and I hope to see some SPC-1 and SPC-2 benchmark numbers published soon.
The DS8700 is compatible for Metro Mirror, Global Mirror, and Metro/Global Mirror with the rest of the DS8000 series, as well as the ESS model 750, ESS model 800 and DS6000 series.
New 600GB FC and FDE drives
IBM now offers [600GB drives] for the DS4700 and DS5020 disk systems, as well as the EXP520 and EXP810 expansion drawers. In each case, we are able to pack up to 16 drives into a 3U enclosure.
Personally, I think the DS5020 should have been given a DS4xxx designation, as it resembles the DS4700
more than the other models of the DS5000 series. Back in 2006-2007, I was the marketing strategist for IBM System Storage product line, and part of my job involved all of the meetings to name or rename products. Mostly I gave reasons why products should NOT be renamed, and why it was important to name the products correctly at the beginning.
IBM System Storage SAN Volume Controller hardware and software
Fellow IBM master inventory Barry Whyte has been covering the latest on the [SVC 2145-CF8 hardware]. IBM put out a press release last week on this, and today is the formal announcement with prices and details. Barry's latest post
[SVC CF8 hardware and SSD in depth] covers just part of the entire
The other part of the announcement was the [SVC 5.1 software] which can be loaded
on earlier SVC models 8F2, 8F4, and 8G4 to gain better performance and functionality.
To avoid confusion on what is hardware machine type/model (2145-CF8 or 2145-8A4) and what is software program (5639-VC5 or 5639-VW2), IBM has introduced two new [Solution Offering Identifiers]:
5465-028 Standard SAN Volume Controller
5465-029 Entry Edition SAN Volume Controller
The latter is designed for smaller deployments, supports only a single SVC node-pair managing up to
150 disk drives, available in Raven Black or Flamingo Pink.
EXN3000 and EXP5060 Expansion Drawers
IBM offers the [EXN3000 for the IBM N series]. These expansion drawers can pack 24 drives in a 4U enclosure. The drives can either be all-SAS, or all-SATA, supporting 300GB, 450GB, 500GB and 1TB size capacity drives.
The [EXP5060 for the IBM DS5000 series] is a high-density expansion drawer that can pack up to 60 drives into a 4U enclosure. A DS5100 or DS5300
can handle up to eight of these expansion drawers, for a total of 480 drives.
Pre-installed with Tivoli Storage Productivity Center Basic Edition. Basic Edition can be upgraded with license keys to support Data, Disk and Standard Edition to extend support and functionality to report and manage XIV, N series, and non-IBM disk systems.
Pre-installed with Tivoli Key Lifecycle Manager (TKLM). This can be used to manage the Full Disk Encryption (FDE) encryption-capable disk drives in the DS8000 and DS5000, as well as LTO and TS1100 series tape drives.
IBM Tivoli Storage FlashCopy Manager v2.1
The [IBM Tivoli Storage FlashCopy Manager V2.1] replaces two products in one. IBM used
to offer IBM Tivoli Storage Manager for Copy Services (TSM for CS) that protected Windows application data, and IBM Tivoli Storage Manager for Advanced Copy Services (TSM for ACS) that protected AIX application data.
The new product has some excellent advantages. FlashCopy Manager offers application-aware backup of LUNs containing SAP, Oracle, DB2, SQL server and Microsoft Exchange data. It can support IBM DS8000, SVC and XIV point-in-time copy functions, as well as the Volume Shadow Copy Services (VSS) interfaces of the IBM DS5000, DS4000 and DS3000 series disk systems. It is priced by the amount of TB you copy, not on the speed or number of CPU processors inside the server.
Don't let the name fool you. IBM FlashCopy Manager does not require that you use Tivoli Storage Manager (TSM) as your backup product. You can run IBM FlashCopy Manager on its own, and it will manage your FlashCopy target versions on disk, and these can be backed up to tape or another disk using any backup product. However, if you are lucky enough to also be using TSM, then there is optional integration that allows TSM to manage the target copies, move them to tape, inventory them in its DB2 database, and provide complete reporting.
Yup, that's a lot to announce in one day. And this was just the disk-related portion of the launch!
In his Backup Blog, fellow blogger Scott Waterhouse from EMC has yet another post about Tivoli Storage Manager (TSM) titled [TSM and the Elephant]. He argues that only the cost of new TSM servers should be considered in any comparison, on the assumption that if you have to deploy another server, you have to attach to it fresh new disk storage, a brand new tape library, and hire an independent group of backup administrators to manage. Of course, that is bull, people use much of existing infrastructure and existing skilled labor pool every time new servers are added, as I tried to point out in my post [TSM Economies of Scale].
However, Scott does suggest that we should look at all the costs, not just the cost of a new server, which we in the industry call Total Cost of Ownership (TCO). Here is an excerpt:
Final point: there is actually a really important secondary point here--what is the TCO of your backup infrastructure. In some ways, TSM is one of the most expensive (number of servers and tape drives, for example), relative to other backup applications. However, I think it would be a really interesting exercise to critically examine the TCO of the various backup applications at different scales to evaluate if there is any genuine cost differentiation between them.
Fortunately, I have a recent TCO/ROI analysis for a large customer in the Eastern United States that compares their existing EMC Legato deployment to a new proposed TSM deployment. The assessment was performed by our IBM Tivoli ROI Analyst team, using a tool developed by Alinean. The process compares the TCO of the currently deployed solution (in this case EMC Legato) with the TCO of the proposed replacement solution (in this case IBM TSM) for 55,000 client nodes at expected growth rates over a three year period, and determines the amount of investment, cost savings and other benefits, and return on investment (ROI).
Here are the results:
"A risk adjusted analysis of the proposed solution's impact was conducted and it was projected that implementing the proposed solutions resulted in $16,174,919 of 3 year cumulative benefits. Of these projected benefits, $8,015,692 are direct benefits and $8,159,227 are indirect benefits.
Top cumulative benefits for the project include:
Backup Coverage Risk Avoidance - $6,749,796
Reduction in Maintenance of Competitive Products - $1,576,000
Reduction in Existing Tivoli Maintenance (Storage and Monitoring) - $1,490,000
IT Operations Labor Savings - Storage Management - $982,919
Network Bandwidth Savings - $575,196
Standardization - $366,667
Future cost avoidance of addtional competitive licenses - $350,000
These benefits can be grouped regarding business impact as:
$6,456,025 in IT cost reductions
$1,559,667 in business operating efficiency improvements
$8,159,227 in business strategic advantage benefits
The proposed project is expected to help the company meet the following goals and drive the following benefits:
Reduce Business Risks $6,749,796
Consolidate and Standardize IT Infrastructure $4,975,667
Reduce IT Infrastructure Costs $2,057,107
Improve IT System Availability / Service Levels $1,409,431
Improve IT Staff Efficiency / Productivity $982,919
To implement the proposed project will require a 3 year cumulative investment of $5,760,094 including:
$0 in initial expenses
$4,650,000 in capital expenditures
$1,110,094 in operating expenditures
Comparing the costs and benefits of the proposed project using discounted cash flow analysis and factoring in a risk-adjusted discount rate of 9.5%, the proposed business case predicts:
Risk Adjusted Return on Investment (RA ROI) of 172%
Return on Investment (ROI) of 181%
Net Present Value (NPV) savings of $8,425,014
Payback period of 9.0 month(s)
Note: The project has been risk-adjusted for an overall deployment schedule of 5 months."
IBM Tivoli Storage Manager uses less bandwidth, fewer disk and tape storage resources than EMC Legato. For even a large deployment of this kind, payback period is only NINE MONTHS. Generally, if you can get a new proposed investment to have less than 24 month payback period you have enough to get both CFO and CIO excited, so this one is a no-brainer.
Perhaps this helps explain why TSM enjoys such a larger marketshare than EMC Legato in the backup software marketplace. No doubt Scott might be able to come up with a counter-example, a very small business with fewer than 10 employees where an EMC Legato deployment might be less expensive than a comparable TSM deployment. However, when it comes to scalability, TSM is king. The majority of the Fortune 1000 companies use Tivoli Storage Manager, and IBM uses TSM internally for its own IT, managed storage services, and cloud computing facilities.
It's Tuesday, and that means more IBM announcements!
I haven't even finished blogging about all the other stuff that got announced last week, and here we are with more announcements. Since IBM's big [Pulse 2010 Conference] is next week, I thought I would cover this week's announcement on Tivoli Storage Manager (TSM) v6.2 release. Here are the highlights:
Client-Side Data Deduplication
This is sometimes referred to as "source-side" deduplication, as storage admins can get confused on which servers are clients in a TSM client-server deployment. The idea is to identify duplicates at the TSM client node, before sending to the TSM server. This is done at the block level, so even files that are similar but not identical, such as slight variations from a master copy, can benefit. The dedupe process is based on a shared index across all clients, and the TSM server, so if you have a file that is similar to a file on a different node, the duplicate blocks that are identical in both would be deduplicated.
This feature is available for both backup and archive data, and can also be useful for archives using the IBM System Storage Archive Manager (SSAM) v6.2 interface.
Simplified management of Server virtualization
TSM 6.2 improves its support of VMware guests by adding auto-discovery. Now, when you spontaneously create a new virtual machine OS guest image, you won't have to tell TSM, it will discover this automatically! TSM's legendary support of VMware Consolidated Backup (VCB) now eliminates the manual process of keeping track of guest images. TSM also added support of the Vstorage API for file level backup and recovery.
While IBM is the #1 reseller of VMware, we also support other forms of server virtualization. In this release, IBM adds support for Microsoft Hyper-V, including support using Microsoft's Volume Shadow Copy Services (VSS).
Automated Client Deployment
Do you have clients at all different levels of TSM backup-archive client code deployed all over the place? TSM v6.2 can upgrade these clients up to the latest client level automatically, using push technology, from any client running v5.4 and above. This can be scheduled so that only certain clients are upgraded at a time.
Simultaneous Background Tasks
The TSM server has many background administrative tasks:
Migration of data from one storage pool to another, based on policies, such as moving backups and archives on a disk pool over to a tape pools to make room for new incoming data.
Storage pool backup, typically data on a disk pool is copied to a tape pool to be kept off-site.
Copy active data. In TSM terminology, if you have multiple backup versions, the most recent version is called the active version, and the older versions are called inactive. TSM can copy just the active versions to a separate, smaller disk pool.
In previous releases, these were done one at a time, so it could make for a long service window. With TSM v6.2, these three tasks are now run simultaneously, in parallel, so that they all get done in less time, greatly reducing the server maintenance window, and freeing up tape drives for incoming backup and archive data. Often, the same file on a disk pool is going to be processed by two or more of these scheduled tasks, so it makes sense to read it once and do all the copies and migrations at one time while the data is in buffer memory.
Enhanced Security during Data Transmission
Previous releases of TSM offered secure in-flight transmission of data for Windows and AIX clients. This security uses Secure Socket Layer (SSL) with 256-bit AES encryption. With TSM v6.2, this feature is expanded to support Linux, HP-UX and Solaris.
Improved support for Enterprise Resource Planning (ERP) applications
I remember back when we used to call these TDPs (Tivoli Data Protectors). TSM for ERP allows backup of ERP applications, seemlessly integrating with database-specific tools like IBM DB2, Oracle RMAN, and SAP BR*Tools. This allows one-to-many and many-to-one configurations between SAP servers and TSM servers. In other words, you can have one SAP server backup to several TSM servers, or several SAP servers backup to a single TSM server. This is done by splitting up data bases into "sub-database objects", and then process each object separately. This can be extremely helpful if you have databases over 1TB in size. In the event that backing up an object fails and has to be re-started, it does not impact the backup of the other objects.
Well, it feels like Tuesday and you know what that means... "IBM Announcement Day!" Actually, today is Wednesday, but since Monday was Memorial Day holiday here in the USA, my week is day-shifted. Yesterday, IBM announced its latest IBM FlashCopy Manager v2.2 release. Fellow blogger, Del Hoobler (IBM) has also posted something on this out atthe [Tivoli Storage Blog].
IBM FlashCopy Manager replaces two previous products. One was called Tivoli Storage Manager for Copy Services, the other was called Tivoli Storage Manager for Advanced Copy Services. To say people were confused between these two was an understatement, the first was for Windows, and the second was for UNIX and Linux operating systems. The solution? A new product that replaces both of these former products to support Windows, UNIX and Linux! Thus, IBM FlashCopy Manager was born. I introduced this product back in 2009 in my post [New DS8700 and other announcements].
IBM Tivoli Storage FlashCopy Manager provides what most people with "N series SnapManager envy" are looking for: application-aware point-in-time copies. This product takes advantage of the underlying point-in-time interfaces available on various disk storage systems:
FlashCopy on the DS8000 and SAN Volume Controller (SVC)
Snapshot on the XIV storage system
Volume Shadow Copy Services (VSS) interface on the DS3000, DS4000, DS5000 and non-IBM gear that supports this Microsoft Windows protocol
For Windows, IBM FlashCopy Manager can coordinate the backup of Microsoft Exchange and SQL Server. The new version 2.2 adds support for Exchange 2010 and SQL Server 2008 R2. This includes the ability to recover an individual mailbox or mail item from an Exchange backup. The data can be recovered directly to an Exchange server, or to a PST file.
For UNIX and Linux, IBM FlashCopy Manager can coordinate the backup of DB2, SAP and Oracle databases. Version 2.2 adds support specific Linux and Solaris operating systems, and provides a new capability for database cloning. Basically, database cloning restores a database under a new name with all the appropriate changes to allow its use for other purposes, like development, test or education training. A new "fcmcli" command line interface allows IBM FlashCopy Manager to be used for custom applications or file systems.
A common misperception is that IBM FlashCopy Manager requires IBM Tivoli Storage Manager backup software to function. That is not true. You have two options:
In Stand-alone mode, it's just you, the application, IBM FlashCopy Manager and your disk system. IBM FlashCopy Manager coordinates the point-in-time copies, maintains the correct number of versions, and allows you to backup and restore directly disk-to-disk.
Unified Recovery Management with Tivoli Storage Manager
Of course, the risk with relying only on point-in-time copies is that in most cases, they are on the same disk system as the original data. The exception being virtual disks from the SAN Volume Controller. IBM FlashCopy Manager can be combined with IBM Tivoli Storage Manager so that the point-in-time copies can be copied off to a local or remote TSM server, so that if the disk system that contains both the source and the point-in-time copies fails, you have a backup copy from TSM. In this approach, you can still restore from the point-in-time copies, but you can also restore from the TSM backups as well.
IBM FlashCopy Manager is an excellent platform to connect application-aware fucntionality with hardware-based copy services.