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8 Krypton

Creating a Meta TDEV

Hi Team,

can any one explain me the rteason for creating a meta TDEV...since it is just a pointer...pointing to the data in the pool...then what is the use of having a meta TDEV...apart from getting more cache slots.

pls note that i am not exceeding the TDEV size more than 240GB.

Regds,

Mannan

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4 Replies
8 Krypton

Re: Creating a Meta TDEV

TDEV is a host addressable device, striped meta device provides additional performance benefits from front-end processing perspective. There were some discussions around this topic on this forum.

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8 Krypton

Re: Creating a Meta TDEV

As a general rule of thumb I make anything over 100gb a meta.  In my unscientific tests that is where my sweet spot for performance was.

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8 Krypton

Re: Creating a Meta TDEV

Thanks dynamox...but if you pls dont mind can you explain in detail...i am really confues because as if a device is just pointers towards data in TDATs then how will a strip of a pointer help...

i know i am missing some point but dont know what ...

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8 Krypton

Re: Creating a Meta TDEV

A single logical device can only have 8 outstanding reads per slice per device (read: tdev on FA slice) so when you have a meta thin single tdev it will have less outstanding read request potential than a stripped meta - which means your random read performance will be impacted.

In addition a meta device will have a higher write pending limit than a single device - which can, if you ever get near your wp limit, have a benefit.

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