Main problem is reporting files that are not accessible. At least one
copy should always be available. There was some talking about how to
resolve this but I don't know how it ended. My ideal would have been
file catalogs ask directly the SRM but the developers were of another
opinion and wanted to store accessibility information in the catalog
itself.
cheers
alessandra
Andrew McNab wrote:
> Greig A Cowan wrote:
>>
>> Just to clarify, I don't have a paper on resilient dCache, I was
>> talking about sharing an SRM between geographically separate sites.
>>
>> However, I have just created this page:
>>
>> http://www.gridpp.ac.uk/wiki/Resilient_dCache
>>
>> that documents my experiences with resilient dCache over the past couple
>> of days. It's only running on a single box with ~25GB of storage so it's
>> not exactly at the scale of running across an entire batch farm.
>> Unfortunately we don't have spare clusters lying around, but it's a
>> start.
>>
>> Comments/questions welcome.
>
> Does dCache's SRM check that the box hosting the pool is online
> when the SRM answers a query about one of its files? ie is the
> issue about not using resilient dCache just that a box/pool
> could go offline, or that plus the danger that the SRM will be
> falsely claiming to have files that are now offline?
>
> Clearly, having a few percent less storage online than you have
> in the racks isn't the end of the world (even if there are files
> on them), but _reporting_ that you have files on those inaccessible
> disks leads to job failures.
>
> Cheers,
>
> Andrew
>
> -------------------------------------------------------------------
> Dr Andrew McNab [log in to unmask] +44-(0)161-275-4227
> Co-ordinator of Security Middleware Groups, GridPP & Manchester HEP
> GridSite: www.gridsite.org Personal stuff: www.gridlock.org.uk
--
*******************************************
* Dr Alessandra Forti *
* Technical Coordinator - NorthGrid Tier2 *
* http://www.hep.man.ac.uk/u/aforti *
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