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Shailender_cho1
24 Posts
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1717
November 11th, 2013 10:00
Tdev size
I believe when we create tdev and do not bind to any pool, it should be in Global memory. What will be the size of unbound tdev (eg 100GB)?
Thanks,
Shailender
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Posted November 11th, 2013 11:00
Size of the TDEV does not change when it is bound vs. un-bound. It simply is made ready when it has a pool for storage.
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Posted November 11th, 2013 14:00
If this is the case, where that tdev will be created till its unbound?
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Posted November 11th, 2013 14:00
If we create five 200 GB tdev and forget to add to pool, will that occupy complete global memory?
1068
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Posted November 11th, 2013 14:00
Same place as after it is bound to a pool, global memory.
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Posted November 11th, 2013 15:00
No, just its metadata will reside in global memory (no different than any other volume). You won't be able to store any real data on it until it has been bound to a pool.
Sent from my iPhone
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Posted November 11th, 2013 18:00
What is the size of that metadata? It should be in bytes or kilobytes. How to calculate that size? I want this information for capacity planning.
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Posted November 12th, 2013 15:00
May I please get answer to my question?
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Posted February 1st, 2014 05:00
Hello Shailender.
A TDEV would use 143 KB of cache and an additional 8 KB of cache for every GB of reported device size.
Refer to page 19, "Best Practices for Fast, Simple Capacity Allocation with EMC Symmetrix Virtual Provisioning Technical Note".
hope this helps.
thanks.
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Posted February 3rd, 2014 09:00
This 143 KB statement is no longer accurate (as of 5875) and as such this statement was removed from the document. It is now a far more flexible algorithm.
codyhosterman
286 Posts
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Posted November 12th, 2013 15:00
TDEV cache usage used to be somewhat of a straight up equation, but is now a much more complex algorithm that allows for much greater efficiency. So it is not really something that can be answered here. Contact your EMC account team as they will have tools that can help you with cache sizing and usage.