Hitachi Ops Center​

while allocating luns we dn't use VSM just normal storage and allocate luns VSM is i use for GAD simple question  any other use of VSM

like what are advantages /disadvanatages of choosing VSM if no gad shall we choose its or not? pls clear

Hello Dhruv

There are a couple of reasons to use VSM they are all based on the implementation or use case dependant. VSM stands for Virtual Storage Machine, it allows us to create a virtual identity that makes a single storage array look like multiple arrays each with their own naa ID. It also allows us to 'copy' the id of another system. Hitachi also uses the concept of VSMs and resource groups to multitenant a storage subsystem and carve out resources per user here are a couple of popular use cases. 

• Migrations - Because we can make one array look like another Hitachi Array we can non disruptively migrate systems to new arrays using GAD as an underlying technology. 
• GAD - Its used for Global Active Device, to make it seem to the host like its writing to one array but in the background its writing to 2 arrays or even 4/6 systems. With VSM we can also migrate physical(non-vsm) to virtual(vsm), virtual to physical or virtual to virtual.
• VSSO - Virtual Storage Scale out. Using VSM technology you can using a single vsm scale it across 64 different backend systems. This allows customers to scale out between systems and prove highly performant storage and workload placement.
• Resource Groups - You can also dedicate resources in resource groups & VSMs and create users that only has access to those resources. Often if a system is shared between Mainframe and x86 systems we would do this in my engineer past to ensure mainframe has a portion of cache, ports, disks,etc they can use and adres but also x86 systems, while creating an user and interface for either party to do their own management. 

That being said, I wouldnt over complicate an install if its not needed. If you have need for it, the functionality is there to support it. 

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William Jansen Van Nieuwenhuizen
Hitachi Vantara
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