Category: Tape storage

SOHO backup options

Posted on by Ray in Data, data protection, storage economics, Storage longevity, System effectiveness, Tape storage
© 2010 RDX Storage Alliance. All Rights Reserved. (From their website)
© 2010 RDX Storage Alliance. All Rights Reserved. (From their website)

I must admit, even though I have disparaged DVD archive life (see CDs and DVDs longevity questioned) I still backup my work desktops/family computers to DVD and DVDdl disks.  It’s cheap (on sale 100 DVDs cost about $30 and DVDdl ~2.5 that much) and it’s convenient (no need for additional software, outside storage fees, or additional drives).  For offsite backups I take the monthly backups and store them in a safety deposit box.

But my partner (and wife) said “Your time is worth something, every time you have to swap DVDs you could be doing something else.” (… like helping around the house.)

She followed up by saying “Couldn’t you use something that was start it and forget it til it was done.”

Well this got me to thinking (as well as having multiple media errors in my latest DVDdl full backup), there’s got to be a better way.

The options for SOHO (small office/home office) Offsite backups look to be as follows: (from sexiest to least sexy)

  • Cloud storage for backup – Mozy, Norton Backup, Gladinet, Nasuni, and no doubt many others can provide secure, cloud based backup of desktop, laptop data for Macs and Window systems.  Some of these would require a separate VM or server to connect to the cloud while others would not.  Using the cloud might require the office systems to be left on at nite but that would be a small price to pay to backup your data offsite.   Benefits to cloud storage approaches are that it would get the backups offsite, could be automatically scheduled/scripted to take place off-hours and would require no (or minimal) user intervention to perform.  Disadvantages to this approach is that the office systems would need to be left powered on, backup data is out of your control and bandwidth and storage fees would need to be paid.
  • RDX devices – these are removable NFS accessed disk storage which can support from 40GB to 640GB per cartridge. The devices claim 30yr archive life, which should be fine for SOHO purposes.  Cost of cartridges is probably RDX greatest issue BUT, unlike DVDs you can reuse RDX media if you want to.   Benefits are that RDX would require minimal operator intervention for anything less than 640GB of backup data, backups would be faster (45MB/s), and the data would be under your control.  Disadvantages are the cost of the media (640GB Imation RDX cartridge ~$310) and drives (?), data would not be encrypted unless encrypted at the host, and you would need to move the cartridge data offsite.
  • LTO tape – To my knowledge there is only one vendor out there that makes an iSCSI LTO tape and that is my friends at Spectra Logic but they also make a SAS (6Gb/s) attached LTO-5 tape drive.  It’s unclear which level of LTO technology is supported with the iSCSI drive but even one or two generations down would work for many SOHO shops.  Benefits of LTO tape are minimal operator intervention, long archive life, enterprise class backup technology, faster backups and drive data encryption.  Disadvantages are the cost of the media ($27-$30 for LTO-4 cartridges), drive costs(?), interface costs (if any) and the need to move the cartridges offsite.  I like the iSCSI drive because all one would need is a iSCSI initiator software which can be had easily enough for most desktop systems.
  • DAT tape – I thought these were dead but my good friend John Obeto informed me they are alive and well.  DAT drives support USB 2.0, SAS or parallel SCSI interfaces. Although it’s unclear whether they have drivers for Mac OS/X, Windows shops could probably use them without problem. Benefits are similar to LTO tape above but not as fast and not as long a archive life.  Disadvantages are cartridge cost (320GB DAT cartridge ~$37), drive costs (?) and one would have to move the media offsite.
  • (Blu-ray, Blu-ray dl), DVD, or DVDdl – These are ok but their archive life is miserable (under 2yrs for DVDs at best, see post link above). Benefits are they’res very cheap to use, lowest cost removable media (100GB of data would take ~22 DVDs or 12 DVDdls which at $0.30/ DVD or $0.75 for DVDdl thats  ~$6.60 to $9 per backup), and lowest cost drive (comes optional on most desktops today). Disadvantages are high operator intervention (to swap out disks), more complexity to keep track of each DVDs portion of the backup, more complex media storage (you have a lot more of it), it takes forever (burning 7.7GB to a DVDdl takes around an hour or ~2.1MB/sec.), data encryption would need to be done at the host, and one has to take the media offsite.  I don’t have similar performance data for using Blu-ray  for backups other than Blu-ray dl media costs about $11.50 each (50GB).

Please note this post only discusses Offsite backups. Many SOHOs do not provide offsite backup (risky??) and for online backups I use a spare disk drive attached to every office and family desktop.

Probably other alternatives exist for offsite backups, not the least of which is NAS data replication.  I didn’t list this as most SOHO customers are unlikely to have a secondary location where they could host the replicated data copy and the cost of a 2nd NAS box would need to be added along with the bandwidth between the primary and secondary site.  BUT for those sophisticated SOHO customers out there already using a NAS box for onsite shared storage maybe data replication might make sense. Deduplication backup appliances are another possibility but suffer similar disadvantages to NAS box replication and are even less likely to be already used by SOHO customers.

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Ok where to now.  Given all this I M hoping to get a Blu-ray dl writer in my next iMac.  Let’s see that would cut my DVDdl swaps down by ~3.2X for single layer and ~6.5X for dl Blu-ray.  I could easily live with that until I quadrupled my data storage, again.

Although an iSCSI LTO-5 tape transport would make a real nice addition to the office…

Comments?

Top 10 storage technologies over the last decade

Posted on by Ray in Block Storage, Cloud services, Data, Data compression, Disk storage, Ethernet, FC, File Storage, Networking, Storage, Storage Backup, Storage density, Storage Features, Storage performance, Strategic Inflection Points, System effectiveness, Systems, Tape storage
Aurora's Perception or I Schrive When I See Technology by Wonderlane (cc) (from Flickr)
Aurora's Perception or I Schrive When I See Technology by Wonderlane (cc) (from Flickr)

Some of these technologies were in development prior to 2000, some were available in other domains but not in storage, and some were in a few subsystems but had yet to become popular as they are today.  In no particular order here are my top 10 storage technologies for the decade:

  1. NAND based SSDs – DRAM and other technology solid state drives (SSDs) were available last century but over the last decade NAND Flash based devices have dominated SSD technology and have altered the storage industry forever more.  Today, it’s nigh impossible to find enterprise class storage that doesn’t support NAND SSDs.
  2. GMR head– Giant Magneto Resistance disk heads have become common place over the last decade and have allowed disk drive manufacturers to double data density every 18-24 months.  Now GMR heads are starting to transition over to tape storage and will enable that technology to increase data density dramatically
  3. Data Deduplication – Deduplication technologies emerged over the last decade as a complement to higher density disk drives as a means to more efficiently backup data.  Deduplication technology can be found in many different forms today, ranging from file and block storage systems, backup storage systems, to backup software only solutions.
  4. Thin provisioning – No one would argue that thin provisioning emerged last century but it took the last decade to really find its place in the storage pantheon.  One almost cannot find a data center class storage device that does not support thin provisioning today.
  5. Scale-out storage – Last century if you wanted to get higher IOPS from a storage subsystem you could add cache or disk drives but at some point you hit a subsystem performance wall.  With scale-out storage, one can now add more processing elements to a storage system cluster without having to replace the controller to obtain more IO processing power.  The link reference talks about the use of commodity hardware to provide added performance but scale-out storage can also be done with non-commodity hardware (see Hitachi’s VSP vs. VMAX).
  6. Storage virtualization – server virtualization has taken off as the dominant data center paradigm over the last decade but a counterpart to this in storage has also become more viable as well.  Storage virtualization was originally used to migrate data from old subsystems to new storage but today can be used to manage and migrate data over PBs of physical storage dynamically optimizing data placement for cost and/or performance.
  7. LTO tape – When IBM dominated IT in the mid to late last century, the tape format dejour always matched IBM’s tape technology.  As the decade dawned, IBM was no longer the dominant player and tape technology was starting to diverge into a babble of differing formats.  As a result, IBM, Quantum, and HP put their technology together and created a standard tape format, called LTO, which has become the new dominant tape format for the data center.
  8. Cloud storage – Unclear just when over the last decade cloud storage emerged but it seemed to be a supplement to cloud computing that also appeared this past decade.  Storage service providers had existed earlier but due to bandwidth limitations and storage costs didn’t survive the dotcom bubble. But over this past decade both bandwidth and storage costs have come down considerably and cloud storage has now become a viable technological solution to many data center issues.
  9. iSCSI – SCSI has taken on many forms over the last couple of decades but iSCSI has the altered the dominant block storage paradigm from a single, pure FC based SAN to a plurality of technologies.  Nowadays, SMB shops can have block storage without the cost and complexity of FC SANs over the LAN networking technology they already use.
  10. FCoE – One could argue that this technology is still maturing today but once again SCSI has taken opened up another way to access storage. FCoE has the potential to offer all the robustness and performance of FC SANs over data center Ethernet hardware simplifying and unifying data center networking onto one technology.

No doubt others would differ on their top 10 storage technologies over the last decade but I strived to find technologies that significantly changed data storage that existed in 2000 vs. today.  These 10 seemed to me to fit the bill better than most.

Comments?

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

Posted on by Ray in Data, Data efficiency, Data growth, data protection, Storage, Tape storage
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.

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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.]

What’s wrong with tape?

Posted on by Ray in Storage, storage economics, Tape storage
StorageTek Automated Cartridge System by brewbooks (cc) (from Flickr)
StorageTek Automated Cartridge System by brewbooks (cc) (from Flickr)

Was on a conference call today with Oracle’s marketing discussing their tape business.  Fred Moore (from Horison Information Systems) was on the call and mentioned something which surprised me.  What’s missing in open and distributed systems was some standalone mechanism to stack volumes onto a single tape cartridge.

The advantages of tape are significant, namely:

  • Low power utilization for offline or nearline storage
  • Cheap media, drives, and automation systems
  • Good sequential throughput
  • Good cartridge density

But most of these advantages fade when cartridge capacity utilization drops.  One way to increase cartridge capacity utilization is to stack multiple tape volumes on a single cartridge.

Mainframes (like system/z) have had cartridge stacking since the late 90’s.  Such capabilities came about due to the increasing cartridge capacities then available. Advance a decade and the problem still exists, Oracle’s StorageTek T10000 has a 1TB cartridge capacity and LTO-5 supports 1.5TB per cartridge both uncompressed.  Nonetheless, open or distributed systems still have no tape stacking capability.

Although I agree with Fred that volume stacking is missing in open systems, but does it really need such a thing.  Currently it seems open systems uses tape for backups, archive data and the occasional batch run.  Automated hierarchical storage management can readily fill up tape cartridges by holding their data movement to tape until enough data is ready to be moved.  On the other hand, backups by their very nature create large sequential streams of data which should result in high capacity utilization except for the last tape in a series.  Which only leaves the problem of occasional batch runs using large datasets or files.

I believe most batch processing today already takes place on the mainframe, leaving relatively little for open or distributed systems.  There are certainly some verticals that do lots of batch processing, for example banks and telcos.  But most heavy batch users grew up in the heyday of the mainframe and are still using them today.

Condor notwithstanding, open and distributed systems never had any sophisticated batch processing capabilities readily available on the mainframe. As such, of those new companies that need batch processing, my guess is that they start with open and as their needs for batch grow move these applications to mainframe.

So the real question becomes how do we increase open systems batch processing.   I don’t think a tape volume stacking system solves that problem.

Given all the above, I see tape use in open being relegated to backup and archive and used less and less for any other activities.

What do you think?