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.
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.
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 ...
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.