[AFS3-std] Quota for max. number of files per volumes

[Hartmut Reuter]

Felix Frank wrote:
>>> Bear in mind that not only are additional RPCs needed, but the volume
>>> dump
>>> format must be extended as well. I expect such an extension to be on the
>>> agenda for the upcoming protocol upgrade?
>>
>> If it's not, well, we should be talking about it. This wouldn't be the
>> only proposal that will require the ability to be backed up!
> 
> As always, I'm not sure whether I'm reading your hints correctly ;-p
> 
> Regardless, here goes for RxOSD (or should I repost in a separate thread?):
> In the header:
>     - tag 'P' (Int32) = OSD policy
> In any vnodes:
>     - tag 'u' (Int32) = last usage time (timestamp)

The "last usage time" is not really necessary. In MR-AFS wipe-decisions
were based on a last usage time kept in the access history vnode and
when I started development of AFS/OSD I thought it would be necessary to
have some thing similar also here. But now I use the atime on the OSD's
partition to find out which objects haven't been used for the longest
time and this technique is much better. So we could drop 'u' and also
the usageTime in the vnode when merging into git.

> In directory vnodes:
>     - tag 'P' (Int32) = Policy Index
> In file vnodes:
>     - tag 'z' (ByteStringWithLength)
>             = string representation of OSD metadata
>     - tag 'x' (Int32) = "OSD file is online" flag
>     - tag 'y' (Int64 via DumpDouble() in OpenAFS)
>             = file length, for OSD-files only

In addition I obviously abused 'm' in the volheader section to transmit
maxfiles rather than minquota. But this can be changed:
'm' could remain minquota and
'Q' could be maxfiles ('Q' because it is a quota for the number of files)

I can change that in the running cell by 1st making sure all volservers
accept 'Q' in the incoming dump and in a 2nd round updating them to
actually send 'Q' and in a 3rd round updating them to do the original
thing with 'm'.

Hartmut
> 
> It strikes me as a little odd myself for me to propose yet another
> 32-bit on-wire timestamp here - I guess we'll have to revamp the RxOSD
> protocol in order to match the upcoming AFS draft?
> 
>  - Felix
> 
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> 


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Hartmut Reuter                  e-mail 		reuter@rzg.mpg.de
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RZG (Rechenzentrum Garching)   	web    http://www.rzg.mpg.de/~hwr
Computing Center of the Max-Planck-Gesellschaft (MPG) and the
Institut fuer Plasmaphysik (IPP)
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