[Lustre-discuss] File joining mechanism

[Tom.Wang]

Lex wrote:
> Hi guys
>
> I have some questions about file joining mechanism in lustre, so i 
> post here and hope you can help me to clarify it :)
>
> As we know, lustre use the split writing and hierarchy striping to 
> distribute file object ( subfile)  to many osts in the cluster. When a 
> client request one file ( over mds metadata ), these objects are 
> retrieve from each ost to client.
>
> So, the question is: when and where these objects are joined together 
> to become a real file ?
File joining is actually joining the file stripe information.  which is 
stored in MDS, so the joining actually happens in MDS, instead of OSS.

Btw: Because of some reasons, joining file feature will be removed 
temporarily in lustre2.0.

Thanks
WangDi
>
> Just guess, are there joined together in OSSs? If it's true, how these 
> OSSs connect together to join its objects together? ( For example, 
> assuming we have 2 OSSs, each OSS have 1 OST, file are striped across 
> to 2 these OSTs. When a client request a file, i get to object in 2 
> different OST from 2 different OSSs, so how these objects can combined 
> together? )
>
> Any help would be appreciated :)
>
> Many thanks
>
>
>
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