Oracle (finally) releases StorageTek VSM6

[Full disclosure: I helped develop the underlying hardware for VSM 1-3 and also way back, worked on HSC for StorageTek libraries.]

Virtual Storage Manager System 6 (VSM6) is here. Not exactly sure when VSM5 or VSM5E were released but it seems like an awful long time in Internet years.  The new VSM6 migrates the platform to Solaris software and hardware while expanding capacity and improving performance.

What’s VSM?

Oracle StorageTek VSM is a virtual tape system for mainframe, System z environments.  It provides a multi-tiered storage system which includes both physical disk and (optional) tape storage for long term big data requirements for z OS applications.

VSM6 emulates up to 256 virtual IBM tape transports but actually moves data to and from VSM Virtual Tape Storage Subsystem (VTSS) disk storage and backend real tape transports housed in automated tape libraries.  As VSM data ages, it can be migrated out to physical tape such as a StorageTek SL8500 Modular [Tape] Library system that is attached behind the VSM6 VTSS or system controller.

VSM6 offers a number of replication solutions for DR to keep data in multiple sites in synch and to copy data to offsite locations.  In addition, real tape channel extension can be used to extend the VSM storage to span onsite and offsite repositories.

One can cluster together up to 256 VSM VTSSs  into a tapeplex which is then managed under one pane of glass as a single large data repository using HSC software.

What’s new with VSM6?

The new VSM6 hardware increases volatile cache to 128GB from 32GB (in VSM5).  Non-volatile cache goes up as well, now supporting up to ~440MB, up from 256MB in the previous version.  Power, cooling and weight all seem to have also gone up (the wrong direction??) vis a vis VSM5.

The new VSM6 removes the ESCON option of previous generations and moves to 8 FICON and 8 GbE Virtual Library Extension (VLE) links. FICON channels are used for both host access (frontend) and real tape drive access (backend).  VLE was introduced in VSM5 and offers a ZFS based commodity disk tier behind the VSM VTSS for storing data that requires longer residency on disk.  Also, VSM supports a tapeless or disk-only solution for high performance requirements.

System capacity moves from 90TB (gosh that was a while ago) to now support up to 1.2PB of data.  I believe much of this comes from supporting the new T10,000C tape cartridge and drive (5TB uncompressed).  With the ability of VSM to cluster more VSM systems to the tapeplex, system capacity can now reach over 300PB.

Somewhere along the way VSM started supporting triple redundancy  for the VTSS disk storage which provides better availability than RAID6.  Not sure why they thought this was important but it does deal with increasing disk failures.

Oracle stated that VSM6 supports up to 1.5GB/Sec of throughput. Presumably this is landing data on disk or transferring the data to backend tape but not both.  There doesn’t appear to be any standard benchmarking for these sorts of systems so, will take their word for it.

Why would anyone want one?

Well it turns out plenty of mainframe systems use tape for a number of things such as data backup, HSM, and big data batch applications.  Once you get past the sunk  costs for tape transports, automation, cartridges and VSMs, VSM storage can be a pretty competitive data storage solution for the mainframe environment.

The fact that most mainframe environments grew up with tape and have long ago invested in transports, automation and new cartridges probably makes VSM6 an even better buy.  But tape is also making a comeback in open systems with LTO-5 and now LTO-6 coming out and with Oracle’s 5TB T10000C cartridge and IBM’s 4TB 3592 JC cartridge.

Not to mention Linear Tape File System (LTFS) as a new tape format that provides a file system for tape data which has brought renewed interest in all sorts of tape storage applications.

Competition not standing still

EMC introduced their Disk Library for Mainframe 6000 (DLm6000) product that supports two different backends to deal with the diversity of tape use in the mainframe environment.  Moreover, IBM has continuously enhanced their Virtual Tape Server the TS7700 but I would have to say it doesn’t come close to these capacities.

Lately, when I talked with long time StorageTek tape mainframe customers they have all said the same thing. When is VSM6 coming out and when will Oracle get their act in gear and start supporting us again.  Hopefully this signals a new emphasis on this market.  Although who is losing and who is winning in the mainframe tape market is the subject of much debate, there is no doubt that the lack of any update to VSM has hurt Oracle StorageTek tape business.

Something tells me that Oracle may have fixed this problem.  We hope that we start to see some more timely VSM enhancements in the future, for their sake and especially for their customers.




Image credit: Interior of StorageTek tape library at NERSC (2) by Derrick Coetzee


IBM boosts System z processing speed

At this week’s Hot Chips Conference Brian Curran, IBM Distinguished Engineer discussed their recently announced, new faster processing chip for System z mainframe environments that runs at 5.2Ghz.  (FYI, the first 31 minutes of the YouTube video link above are from Brian’s session and the first 10 minutes provides a good overview of the chip.)

Brian discussed System z environments which mainly run large mission critical applications such as OLTP, which use large instruction and data caches.  Also System Z is now being used for Linux consolidation with 1000s of Linux machines running on a mainframe.

The numbers

The new z196 processing core provides up to a 40% improvement executing mainframe applications.  Also, the new processor chip was measured at 50 Billion instructions per second (Bips).

In addition, the z196 achieved a remarkable 40% code thread constant improvement and another 20-30% throughput performance improvement was attainable through re-compilation.  Moreover, they have shown a sustained system execution throughput (multi-thread/multi-application) of 400 Bips.  All this was done without increasing energy consumption over current generation System z processing chips.

Cache everywhere and lots of it

The z196 chip is a 45nm 1.4B transistor, quad core processor with two onboard, special purpose co-processors for cryptographic and compression acceleration. The z196 processing chip has 64KB L1 private I-cache (instruction) and 128KB private D-cache (data), with a 1.5MB private L2 cache. The two L1 & L2 SRAM caches are replicated for each of the four cores.  There is an onboard shared 24MB eDRAM L3 cache as well. With a full 5.2Ghz clock speed across all cores in the z196 quad-core processor group.

Each z196 processing core supports out-of-order instruction execution with a 40 instruction window size.   Further, all data is protected with ECC and hardened with parity and/or duplication for processing steps.

Six of these z196 processing chips combine together to form a processor node on a multi-chip module (MCM).  There is an industry first additional 192MB eDRAM L4 cache shared across the six processing chips on a MCM.  Each System z MCM can interface with up to 750GB of main memory.

In a System z processing frame there can be up to four MCMs, which then provides a total of 96 processing cores.  With the four MCMs, System z can address ~3TB of main memory.  Each MCM is fully interconnected with all other MCMs in a processing frame via a pair of redundant fabric interfaces.

System z is a CISC architecture which with the Z196 has passed the 1000 instruction count barrier (1079 instructions).  Whew, glad I am not coding in Assembler anymore.

IBM formerly announced the chip a month ago and it will be in shipping System z product later this year.

There was some mention by WSJ blogs of Power systems 7+ going up to 5.5Ghz   but I couldn’t locate a more definitive source for that news.


Image: Z10 by Roberto Berlim


Why Bus-Tech, why now – Mainframe/System z data growth

Z10 by Roberto Berlim (cc) (from Flickr)
Z10 by Roberto Berlim (cc) (from Flickr)

Yesterday, EMC announced the purchase of Bus-Tech, their partner in mainframe or System z attachment for the Disk Library Mainframe (DLm) product line.

The success of open systems mainframe attach products based on Bus-Tech or competitive technology is subject to some debate but it’s the only inexpensive way to bring such functionality into mainframes.  The other, more expensive approach is to build in System z attach directly into the hardware/software for the storage system.

Most mainframer’s know that FC and FICON (System z storage interface) utilize the same underlying transport technology.  However, FICON has a few crucial differences when it comes to data integrity, device commands and other nuances which make easy interoperability more of a challenge.

But all that just talks about the underlying hardware when you factor in disk layout (CKD), tape format, disk and tape commands (CCWs), System z interoperability can become quite an undertaking.

Bus-Tech’s virtual tape library maps mainframe tape/tape library commands and FICON protocols into standard FC and tape SCSI command sets. This way one could theoretically attach anybody’s open system tape or virtual tape system onto System z.  Looking at Bus-Tech’s partner list, there were quite a few organizations including Hitachi, NetApp, HP and others aside from EMC using them to do so.

Surprise – Mainframe data growth

Why is there such high interest in mainframes? Mainframe data is big and growing, in some markets almost at open systems/distributed systems growth rates.  I always thought mainframes made better use of data storage, had better utilization, and controlled data growth better.  However, this can only delay growth, it can’t stop it.

Although I have no hard numbers to back up my mainframe data market or growth rates, I do have anecdotal evidence.  I was talking with an admin at one big financial firm a while back and he casually mentioned they had 1.5PB of mainframe data storage under management!  I didn’t think this was possible – he replied not only was this possible, he was certain they weren’t the largest in their vertical/East coast area by any means .

Ok so mainframe data is big and needs lot’s of storage but this also means that mainframe backup needs storage as well.

Surprise 2 – dedupe works great on mainframes

Which brings us back to EMC DLm and their deduplication option.  Recently, EMC announced a deduplication storage target for disk library data used as an alternative to their previous CLARiion target.  This just happens to be a Data Domain 880 appliance behind a DLm engine.

Another surprise, data deduplication works great for mainframe backup data.  It turns out that z/OS users have been doing incremental and full backups for decades.  Obviously, anytime some system uses full backups, dedupe technology can reduce storage requirements substantially.

I talked recently with Tom Meehan at Innovation Data Processing, creators of FDR, one of only two remaining mainframe backup packages (the other being IBM DFSMShsm).  He re-iterated that deduplication works just fine on mainframes assuming you can separate the meta-data from actual backup data.

System z and distributed systems

In the mean time, this past July, IBM recently announced the zBX, System z Blade eXtension hardware system which incorporates Power7 blade servers running AIX into and under System z management and control.  As such, the zBX brings some of the reliability and availability of System z to the AIX open systems environment.

IBM had already supported Linux on System z but that was just a software port.  With zBX, System z could now support open systems hardware as well.  Where this goes from here is anybody’s guess but it’s not a far stretch to talk about running x86 servers under System z’s umbrella.


So there you have it, Bus-Tech is the front-end of EMC DLm system.  As such, it made logical sense if EMC was going to focus more resources in the mainframe dedupe market space to lock up Bus-Tech, a critical technology partner.  Also, given market valuations these days, perhaps the opportunity was too good to pass up.

However, this now leaves Luminex as the last standing independent vendor to provide mainframe attach for open systems.  Luminex and EMC Data Domain already have a “meet-in-the-channel” model to sell low-end deduplication appliances to the mainframe market.  But with the Bus-Tech acquisition we see this slowly moving away and current non-EMC Bus-Tech partners migrating to Luminex or abandoning the mainframe attach market altogether.

[I almost spun up a whole section on CCWs, CKD and other mainframe I/O oddities but it would have detracted from this post’s main topic.  Perhaps, another post will cover mainframe IO oddities, stay tuned.]