Going Tapeless in Enterprise

by dave on January 28, 2009


I was asked the other day about the potential for finally going tapeless in Commercial and Enterprise spaces.  Truth be told, this is becoming a more common occurence as those mechanical beasts hit the tail-end of their maintenance windows.  With that in mind, what are some (not all) of the business drivers that move enterprises from tape to disk (or other mediums)?

“Tape is Dead!” has echoed through the halls of storage IT for quite some time.  It’s been an ideological pursuit of the “next generation backup” mantra hawked by the Tier Ones in the storage space.  What has been noted is the continued price depreciation of disk as capacity has increased, the tighter compliance metrics from government agencies, as well as the legacy of natural disasters that have arrived on the scene since 2001.  Let’s unpack these a bit.

Price Depreciations and Increased Capacity

It was only a few years ago that large capacity drives (SATA) were introduced to the market at roughly $400.00 per drive.  I remember purchasing 750Gb or 1Tb drives for what seemed like hundreds of dollars compared to the $80.00 LTO-3 tapes that our business was using for daily backups.  However, flashing forward to this past week, 2Tb drives are being brought out (Western Digital and Seagate) with list prices of around $299.00!!!  That type of price depreciation coupled with capacity increases points to the rapid rise of disk media for backup storage over and above tape.  Last time I checked, an 800Gb LTO-4 drive (uncompressed, mind you) was $80-90.00 in the channel.  Parity is almost being reached now in terms of price per STORED GB and cannot be ignored.

Tighter Compliance

The reason why compliance was introduced to begin with was based on keeping entities accountable for the data they retained on consumers.  Compliance, then, spilled over to backups since the chain of custody had to be maintained both on active AND inactive data within the environment.  With the failure of offsite storage companies to keep physical media under lock and key (Iron Mountain, for example) writ large on the newsprint every so often, the imperative to keep that data under closer watch has move enterprise to look at purpose-built backup devices such as VTL and Disk Libraries (EMC has a few of those 😉 ).

Natural Disasters

I’ve always referred to natural disasters as “Acts of God.” Regardless of your religious beliefs, these disasters exceed our comprehension of causality and purpose.  Wanton destruction has the unfortunate effect of mangling data communication and causing data failure.  Again, in a similar vein to compliance issues, even in the eye of a storm, chain of custody must be maintained and accountability is still there.  Just because your tapes are offsite, doesn’t mean that you’re going to have an easy ability to recover your data in the event of a NOC or DC failure.  The time for recovery in these cases can be WEEKS or MONTHS, versus days or hours.

Remediating the Problem

Going tapeless solves quite a few problems (while introducing others, of course).  When looked at from the dimensions listed above, there are quick, easy answers that show concept fitment, leaving the actual particulars to be hashed out in the design.

Price Depreciation and Capacity Increase – Tapeless

When looked at from a price standpoint, fixed disk has less of an ongoing OpEx than tape CAN, depending on the nature and methodology of storage.  If tape is being offsited by Iron Mountain, let’s say, you’re paying a fee for each tape carrier, courier (ha!), and for the ongoing storage of that data in their secure facilities.  That being said, if you’re holding that data for a longer period of time (let’s say 7 years), your CapEx is going to be ridiculous compared to holding the same data on mechanical disk within a VTL or DL.

Secondly, there’s the little issue of capacity upgrades.  Looking at LTO tapes, for example, there’s a N-2 support level.  LTO-4 devices, if I recall correctly, can read LTO-2, write/read LTO-3, and write/read LTO-4.  However, you’ll have to upgrade the mechanicals when LTO-5 comes out, etc. etc.  With disk, you simply add additional capacity and either migrate the backup pools or continue with business as usual.  Combining 2:1 compression (a la LTO-4), you’re effectively getting 2Tb of storage on a 1Tb drive AND, when tossing data deduplication into the mix (a la EMC’s EDL1500/3000 series of Disk Libraries), this factor can be EVEN HIGHER! 

Tighter Compliance – Tapeless

When it comes to compliance, the stage is ready made for tapeless enterprises.  Not only is there easier integration with encryption products (remember, LTO-4 requires “chipped” tapes as well as support from the library itself) for data in-band or out-of-band.  Integration with the software used for backup (EMC Networker, for example) can provide the necessary hooks for RSA encryption protocols, etc.  Even further, this data can be replicated in an encrypted state thus providing appropriate proof for chain-of-custody compliance metrics.

Natural Disasters – Tapeless

Where the rubber can really hit the road is with these so-called “Acts of God.”  By using the aforementioned replication capabilities of the primary storage or the VTL/DL arrays themselves, you can move data offsite to a geographically removed NOC/DC with considerations for data recovery in the event of disaster.  Again, we’re not talking the specifics of recovery here…that’s a separate discussion.

Conclusion

This was just a “quick hit” and as such, there’s definitely room to flesh out some of these concepts.  Feel free to respond with corrections, feedback, and clarifications via twitter (@davegraham), Disqus (through the comments section) or FriendFeed.

 

 

 

 

 

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  • As far as the economy of tape versus disk media goes, another issue to think about is compression. Most of our IBM midrange users get 6 to 1 compression on disk versus 2 to 1 on tape. That gives disk a 3 to 1 advantage versus tape. So if a 400 GB tape holds 800 GB compressed, 400 GB of disk holds 2.4 TB compressed. Tape has to be three times cheaper than disk, per raw gigabyte, to compete – and it isn't.

    Another issue here is that on the average, a tape is going to be 2/3 full or less – since it comes in fixed sizes, and you nearly always end up with a backup tape that is not full.

    But the real cost of tape is the cost of the human being that has to handle it at some point – and the increased chances of errors that come from manual handling of tapes.

  • dave

    Brad,

    good points!! thanks for your feedback!

    cheers,

    Dave

  • dave

    Brad,

    good points!! thanks for your feedback!

    cheers,

    Dave

  • As far as the economy of tape versus disk media goes, another issue to think about is compression. Most of our IBM midrange users get 6 to 1 compression on disk versus 2 to 1 on tape. That gives disk a 3 to 1 advantage versus tape. So if a 400 GB tape holds 800 GB compressed, 400 GB of disk holds 2.4 TB compressed. Tape has to be three times cheaper than disk, per raw gigabyte, to compete – and it isn't.

    Another issue here is that on the average, a tape is going to be 2/3 full or less – since it comes in fixed sizes, and you nearly always end up with a backup tape that is not full.

    But the real cost of tape is the cost of the human being that has to handle it at some point – and the increased chances of errors that come from manual handling of tapes.