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Top Ten Reasons Why DAS Will Grow!

By Lee Johns

For a number of years now the relentless growth of SANs has overshadowed the Direct Attached Storage market (DAS). Indeed market studies have shown that while still a large market, DAS is shrinking.  Howeverrecent advances in SAS drives and SAS connectivity, along with market shifts are pointing to a resurgence of DAS. 


I thought I might put forward 10 reasons why over the next 18 months DAS will grow! SO HERE WE GO (drum roll)...


1)    SAS connectivity offers much more functionality that older SCSI cable connections.  Indeed major systems manufacturers, like HP, have introduced SAS connected arrays that can provided a shared storage environment for multiple servers just like a SAN. For smaller environments this offers SAN functionality without the headache of managing a network.


2)    Server Blades are the hotest growth areof the server market. By consolidating servers in a single enclosure, SAS based arrays will in the near future be able to share storage across more servers without using a network with traditional server architectures.


3)    Server Virtualization is the hotest SW growth story in the market.  Using products like VMware forces customers to have to consider how to implement shared storage, and for many using fibre channel storage is too expensive.  SAS connectivity offers a lower cost alternative and is easier to manage, especially for server administrators.  SAS products like the HP MSA 2000sa are VMware certified


4)    Although SAN's have consolidated a huge amount of data there still exists an extraordinary amount of drives in servers today that have not been consolidated for a variety of reasons.  SAS offers a lower cost consolidation play for the drives that have not today been moved to SANs


5)    Ongoing management costs are one of the major issues faced by IT organizations today.  If you don't already have a Fibre Channel SAN and just require shared storage for a few simple applications why look at managing a new fabric and hiring expensive SAN administrators


6)    Applications like Microsoft Exchange are moving more and more storage services inside the application.  They are even recomending DAS for performance. 


7)    Web 2.0 companies are having to think differently about storage implementations b/c of new scale out applications.  They can not afford traditional SAN's and the promise of architecting Storage based on DAS is compelling


8)   Server purchasers can not buy SANs without engaging Storage teams.  They can buy shared SAS storage though and get the same effect


9)    Choice is always important as a consumer.  Products like the HP MSA 2000 offers the choice of Fibre Channel, iSCSI or SAS interconnect, while providing the same basic functionality and management interface. This means you can buy into SAS connected storage with a simple migration path to a future SAN based on iSCSI or Fibre, if you need the future scalability.


10)   AND FINALLY......... COST, COST, COST.  It is an easy way for SMB's to implement shared storage and have you seen the economy lately?!?


What do you think?

Anonymous | ‎08-30-2008 08:57 AM

I agree with you: DAS adoption will soar in behalf price and virtualization.

Anonymous | ‎09-01-2008 11:14 AM

Certainly the "mini-SAN" functionality of the newer SAS based products is a great advantage and I can see it making more headway that the older SCSI based products that did the same thing (ie MSA500) but unfortunately until full support for the virtual environment is available in products like the MSA2000sa, adoption will be impossible.

By this I mean the fact that the MSA2000sa does not currently support shared VMFS which severely limits its usage with VMware.

| ‎09-03-2008 12:13 AM

Hi Mark - Thank you for your comment.  You are correct that support for VMFS and therefore having shared LUN support and the ability to run VMotion is a limiter to SAS adoption in VMware environments.  You will be pleased to know we are working on a fix for a late issue we caught with VMware that caused us to limit this support.  You can expect to have support for the MSA 2000sa for Shared VMFS via an MSA 2000sa firmware update in about 30 Days."

Thanks again!

Anonymous | ‎09-08-2008 05:11 AM

i disagree... DAS tends to die... and look at latest ISS servers releases: DL185 G5 = 12To intern storage ....

leejohnsbladestorage | ‎09-09-2008 03:24 AM

Hi Seyar.   Thanks for your comment.  I posted this blog to raise debate so I'm interested in hearing more.  With regard to the twelve drive ProLiant G5 remember that that is DAS storage and it is a perfect example of Server and Storage convergence and of more DAS being sold.  It also happens to form the basis for our most popular File Server.  

Our recently announced MSA2000sa is a DAS Array capable of being shared just like a typical SAN but without building a network.  To achieve the same flexibility of Storage with Blades which don't have the internal capacity to hold as many drives as a DL 185 we have to do innovative things with DAS outside of the server.      

Once again thanks for your comment and stay tuned to find out more about innovations in DAS

Anonymous | ‎01-18-2009 08:07 PM

One thing that is really missing from the HP small storage systems is controller based replication. The cost of purchasing and maintaining the current EVAs are high and the MSA range cannot (as far as i know) replicate between sites like small boxes from Sun and HDS (soon) can. I guess this is where LeftHand might be coming in?

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