[Lustre-devel] [RFC] two ideas for Meta Data Write Back Cache
di.wang at sun.com
Mon Apr 6 15:02:14 PDT 2009
> 2) "create w/o name" (this is what MDT accepts these days) isn't operation,
> it's partial operation. but for partial operations we already have OSD
> - clear, simple and generic. having one more "partial operations" adds
> nothing besides confusion, IMHO
I am not sure you can( or should) translate all the MD partial
operation into object RPC for these partial
MD operation. For example rename, (a/b ---> c/d, a/b in MDS1, c/d in
RPC goes to MDS1.
1) delete d (entry and object) from c in MDS2.
2) create b entry under c in MDS2.
3) delete b entry under a in MDS1.
So if you do 1) and 2) by object rpc (skip mdd), then you might need
create create all 4 objects
(a and b are local object, c and d are remote object), and permission
check locally (whether
you can delete d under c). Not sure it is a good way. And also some
quota stuff are handled
in these partial operation in remote MDD, so I am not sure we should
skip mdd totally here.
Am I miss sth?
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