Hi Matevz,
The other thing that should go into the cmsd is to avoid doing a “redirect on file not found” for reselection.
This would help immensely in cases like FNAL which uses this for all jobs, causing the multi source CMSSW to pull data that is onsite, from offsite, due to reselection.
(After telling them for 5 years to change, I guess we can tweak the software ;) )
Brian
Sent from my iPhone
> On May 3, 2019, at 6:57 PM, Matevz Tadel <[log in to unmask]> wrote:
>
> Hi,
>
> Andy realized that an option for this already exists -- triedrc=resel
>
> Andy impleented a change in cmsd that allows disabling opening of a new file on reselection, goes under cmsd.sched nomultisrc.
>
> Brian, now we have to propagate this into XrdAdapter.
>
> Matevz
>
>> On 4/18/19 10:45 AM, Andrew Hanushevsky wrote:
>> After some discusion with Matevz, we decided to simplify this, So, it won't be exactly what was outlined but will be functionally the same. This requires soem development in the cmsd. That said, an issue should be cut.
>> Andy
>>> On Thu, 18 Apr 2019, Michal Kamil Simon wrote:
>>> Hi,
>>>
>>> It sounds reasonable to me :-)
>>>
>>> Matevz: could you create an issue in github so we don't loose
>>> track of this topic? ;-)
>>>
>>> Cheers,
>>> Michal
>>> ________________________________________
>>> From: [log in to unmask] [[log in to unmask]] on behalf of Bockelman, Brian [[log in to unmask]]
>>> Sent: 17 April 2019 03:59
>>> To: [log in to unmask]
>>> Cc: xrootd-dev
>>> Subject: Re: Proposal for new opaque URL parameter using= complementing tried=
>>>
>>> Yes! We definitely could benefit from this on the CMS side!
>>>
>>> Sent from my iPhone
>>>
>>>> On Apr 15, 2019, at 5:21 PM, Matevz Tadel <[log in to unmask]> wrote:
>>>>
>>>> Hi,
>>>>
>>>> [This is mostly for Andy, Brian, and Michal.]
>>>>
>>>> In the context of XCache cluster used by CMSSW multi-source jobs there is an issue with cmssw jobs requesting opening of a second source on the cache cluster using the tried= opaque parameter to point to cache server already in use. This leads to creation of another replica of the same file in the cache cluster.
>>>>
>>>> The cache still needs to honor tried= in case there is a problem with the existing server. However, asking for a new "extra" server in the context of cache does not make much sense.
>>>>
>>>> To distinguish these two conditions I propose to introduce a new opaque directive, "using=", used to signal to the redirector that the client is already using the listed servers.
>>>>
>>>> On cmsd side this would be accompanied with a cms.dfs multisource count ("sister" option to cms.dfs retries). These two would then control how many errors and parallel accesses are allowed for a client session.
>>>>
>>>> Does this make sense?
>>>>
>>>> Matevz
>>>>
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