zgz_rever
3 Silver

More information about emulation and protection type

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Hi everyone,

Maybe it is not the place to ask for this but as I found it reading the VMAX documentation, maybe someone can post me a link where I can find more information about these two concepts which keep appearing:

EMULATION type

I really have no idea what it means, does the VMAX emulates some kind of storage layout (defining the allocation unit and other features...)? What could be the benefit of using one emulation type instead of other?

PROTECTION type

Does it has to do with the RAID level? again, what benefits could provide using one instead of other (if it is RAID I know )?

Thank you in advance

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PedalHarder
3 Zinc

Re: More information about emulation and protection type

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The EMULATION type refers to the type of device. Open systems requires a Fixed Block Architecture (FBA) device, while Mainframe needs Count-Key-Data (CKD) for example. So it is the EMULATION type that describes this.

You're right about the protection type relating to RAID. With RAID the costs and benefits come in 3 different areas:

- Protection level. How well is the data protected at the hardware level. In other words the likelihood of data loss in a multiple hard drive scenario.

- Performance. The amount of overhead in performing write operations. A single host write, generates 2 disk writes for RAID1, 4 for RAID 5 and 6 for RAID 6.

- Capacity. The storage capacity overhead in providing data protection. raid 1 = 100%, raid 5/6 25% or 12.5% depending on the number of devices in the raid set.

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PedalHarder
3 Zinc

Re: More information about emulation and protection type

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The EMULATION type refers to the type of device. Open systems requires a Fixed Block Architecture (FBA) device, while Mainframe needs Count-Key-Data (CKD) for example. So it is the EMULATION type that describes this.

You're right about the protection type relating to RAID. With RAID the costs and benefits come in 3 different areas:

- Protection level. How well is the data protected at the hardware level. In other words the likelihood of data loss in a multiple hard drive scenario.

- Performance. The amount of overhead in performing write operations. A single host write, generates 2 disk writes for RAID1, 4 for RAID 5 and 6 for RAID 6.

- Capacity. The storage capacity overhead in providing data protection. raid 1 = 100%, raid 5/6 25% or 12.5% depending on the number of devices in the raid set.

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zgz_rever
3 Silver

Re: More information about emulation and protection type

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Ok, thank you.

About the emulation type, I have an extra question. I can select more options in the emulation type apart from CKD and FBA (AS/400, FBA Celerra, VME512 FBA...), so I guess that the decision about what Emulation type to choose does not only depend on the type of system. What are the others for? How should I select the best for my system?

Thanks again

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dynamox
7 Thorium

Re: More information about emulation and protection type

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for open systems you always use FBA, CKD for mainframes ..it all depends on what system you are trying to provision storage for.

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zgz_rever
3 Silver

Re: More information about emulation and protection type

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I am using an open system but I wonder what are the differences and benefits of, for example, using normal FBA instead of Celerra FBA. As I said in the first post probably these questions does not belong here but I was hoping that someone could provide me a link that gives me this information or at least that clarifies me the differences among all the emulation types.

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dynamox
7 Thorium

Re: More information about emulation and protection type

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different platforms require different emulation, Celerra FBA is when you are present devices to Celerra gateway systems.

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zgz_rever
3 Silver

Re: More information about emulation and protection type

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I may migrate data from the VMAX to a VNX, should I use Celerra FBA instead of normal FBA? Would the migration be possible in case I used FBA?

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dynamox
7 Thorium

Re: More information about emulation and protection type

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if you are migrating from VMAX to VNX ..then FBA is already set ?

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zgz_rever
3 Silver

Re: More information about emulation and protection type

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First I create the device in VMAX. When I do so I must select an emulation type. Imagine I choose FBA. After one year of using that device I decide to move the data to a Celerra device. If I understood correctly, there, the data uses an emulation type called FBA Celerra. Will I be able to do that migration given the fact that the emulation type is different?

Apart from that, imagine that now I use VME512 FBA, will I experience any performance impact since now I am not using the recommended FBA but another "flavour"?

By the way, thank you dynamox for your time!

Message was edited by: zgz_rever

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dynamox
7 Thorium

Re: More information about emulation and protection type

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Celerra is a NAS platform, you would not be able to migrate data at the block level into a platform that uses file systems. I think you are thinking too much into it. You have to use FBA for AIX, Linux, HPUX, Windows, ESX, Solaris., Open VMS.