Toluu

Hu Yoshida

Hu Yoshida, VP and CTO of Hitachi Data Systems, provides his insight into industry issues, discusses in his own words storage best practices, and provides realistic solutions to real storage problems of current and next generation storage environments.

Hitachi Dynamic Provisioning without Thin ProvisioningNovember 19

Hitachi Dynamic Provisioning, HDP, is a feature of the USP V/VM which does virtualization of storage capacity in a pool of storage consisting of multiple RAID array groups. This pool of physical RAID array groups is divided up into 42 MB pages and used on-demand by any of the virtual host volumes using the pool. This enables HDP to provide a number of services.

The first benefit of HDP that everyone thinks of is thin provisioning. Thin Provisioning enables the USP V/VM to fill a request for a LUN allocation, for example 100  GB, with virtual capacity, and thinly provision the LUN with 42 MB pages of real storage capacity as the application starts to write to it. The unused capacity for the 100GB LUN allocation  is then available to be used to thinly provision other LUN allocation requests from the same HDP pool. This helps to increase the utilization of storage by eliminating most of the allocated but unused portion of a LUN.

However, the real reason Hitachi calls this feature Dynamic Provisioning is that it does just that. It enables IT to dynamically provision LUNs from this HDP pool by assigning virtual LUN capacity as quickly as drag and drop. Instead of taking hours to provision a new server with LUNs, HDP can dynamically provision a new server in a matter of minutes.
Another service is thin moves and copies. Since HDP know how many pages are assigned to a LUN allocation when it does a move or copy of that LUN, it only moves or copies the actual

Storage Virtualization or SAN Volume ControllerNovember 10

Recently there has been quite a bit of back and forth between Barry Whyte and myself. In an effort to clear up any misconceptions and more clearly state our differing positions, I’ve outlined a few points that should help our understanding.

As a recap, storage virtualization with the USP V can virtualize storage for direct attached servers and mainframes, as well as SAN attached servers. Based on Barry’s comments, there is no difference than what IBM does with a SAN Volume Controller.  I believe there is a big difference between the USP V and the SVC and other virtualization examples that he cites since they can only provide virtualization for SAN attached storage and servers.

Barry was good enough to give me some use cases in a comment to my last post. This helps to clarify our differences.

Here are my comments on Barry’s use cases:

1. The first use case was how we virtualize existing LUNs. Barry claims there is no difference. I claim there is a big difference.  While there is a disruption to the application, when we disconnect a storage system and reconnect it through the USP, we discover the LUNs and present it back to the application from the USP cache. There is no need to create an “image mode virtual disk” and do a 1-2-1 mapping in a mapping table which becomes a s

Welcome TonyNovember 5

Welcome to Tony Asaro who has just joined the HDS blogging community with his blog, Tony Asaro’s Blog Bytes. Tony is a storage expert and well-known blogger who has blogged for Computerworld, Searchstorage, virtualiron, and his very popular Stor Wars when he was an analyst with the Enterprise Strategy Group.

Tony’s recent blog on storage and the economy makes an excellent good point about the need to implement storage virtualization to increase storage utilization, especially in these economic times where it is critical to reduce capital spend and improve operational expenditures.

While I certainly agree that storage virtualization can increase utilization of storage, it is important to differentiate storage virtualization from SAN virtualization, where the SAN is virtualized to look like storage. With SAN-based virtualization, you may not see a significant increase in utilization and you may see an increase in operational expenditures.

Hitachi does storag

A loaded QuestionNovember 1

Recently I was asked: “Why did Hitachi choose an in-band approach to SAN virtualization?”

This is a bit of a loaded question like: “When did you stop beating your wife?” This question implies that you are beating your wife. How do you answer without appearing to agree to the premise or appearing to be evasive? This is easy to answer if you aren’t married. Then you could just end the discussion by saying that you don’t have a wife.

In terms of the question I was asked, I don’t have to be dragged down into the debates between in band or out of band SAN virtualization, since Hitachi does not do SAN Virtualization.

Hitachi does storage virtualization. SAN virtualization is dependent on the SAN for connectivity and information for mapping physical extents from different storage systems to virtual extents. Hitachi storage virtualization is not dependent on the SAN.

Storage virtualization is enabled by software in the Universal Storage Platform which presents LUNs from externally attached storage systems through its enterprise class storage control unit to servers that can be attached through SAN, DAS, NAS, ESCON, FICON. There is no need to remap the LUNs and no need for a mapping table.

If FCoE or other protocols should happen to replace the SAN in the future, it would not have an impact on storage virtualization, where as SAN virtualization would have to make some major changes to switch from FC to Ethernet. For Hitachi it woul

Green Encryption for StorageOctober 24

With all that was happening at SNW, you may not have noticed our announcement of data at rest encryption for the USP V and USP VM. This encryption can be used to encrypt all internal disk drives, using AES-256, with no throughput or performance impact. In addition this implementation allows a very simple but safe key management scheme.

We call it Green Encryption since it is implemented on the back end RAID Directors of the USP V or VM. This approach enables the introduction of encryption into a storage ecosystem with little or no disruption to existing applications or infrastructure. It is data center friendly since it uses very little additional power (about 2 watt per encrypting director), produces very small amounts of additional heat ( about 3%), and requires no additional rack space or cable plant changes. It can be a non disruptive upgrade to and existing USP V or VM.

Since it sits on the back end, a redundant pair of encryption RAID directors can encrypt data that comes through any or all of the FC or ESCON/FICON front end port directors.  If you were to use switch port encryption or an encryption appliance like Decru, you would have to have this appliance or switch port on every path that you want to encrypt.  This would be much more expensive and generate a lot more heat and power consumption. You would also have to find a solution for key management if there are alternate paths, or access by server clusters. With FC switches and appliances you w