Royal Holloway has being using the weighting system. Our interpretation
is to use a number between 1 and 9, the higher the number indicating
that more files will be copied in. As Wahid suggests a zero apparently
stops new files being copied in without having to mark a file system
read only. This is very useful as it avoids reducing the apparent
available space outside of the ATLAS space-tokens thereby solving
Wahid's second bad experience:
"2. marking a disk read only making sam tests fail".
Duncan
On 17/02/2012 11:25, Wahid Bhimji wrote:
> Hi
>
> Well just to say - I don't think there is anyway that it will break anything.Worst is an unexpected distribution of files.
>
> And for example setting 0 on a filesystem nearing capacity is an easy way of not getting it more full without needing to understand in detail the selection rules.
>
> cheers
>
> Wahid
>
> On 17 Feb 2012, at 11:15, John Bland wrote:
>
>>
>> Hi,
>>
>> Thanks, I only found out of date man pages. Checking again I've found the man pages that came with the package, 'usefully' in the non-standard /opt/lcg/share/man/ directory.
>>
>> The second link is very useful, it's not using weights in the way I was expecting it to, so it will take some more consideration in how to set them up.
>>
>> Being untested I'm slightly less keen to use it now ;0). I'll give it a try when I get time to keep an eye on it.
>>
>> John
>>
>> On 17/02/2012 11:06, Wahid Bhimji wrote:
>>>
>>> Hi John
>>>
>>> I think the only documentation is the man pages
>>>
>>> http://grid-deployment.web.cern.ch/grid-deployment/documentation/LFC_DPM/dpm/man1/dpm-modifyfs.1.html
>>>
>>> for dpm-modifyfs it only tells you
>>> weight:
>>> specifies the weight of the filesystem. This is used during the filesystem selection. The value must be positive. It is recommended to use a value lower than 10.
>>>
>>> but then the page for dpm-buildfsv
>>> http://grid-deployment.web.cern.ch/grid-deployment/documentation/LFC_DPM/dpm/man1/dpm-buildfsv.1.html
>>>
>>> gives you a bit more idea of what will happen if you use different values.
>>> I don't think we have much experience of what will happen in practise except for a very quick test with JP when he was developing. Some experience in production would be very interesting to hear about!
>>>
>>> Cheers
>>>
>>> Wahid
>>>
>>> On 17 Feb 2012, at 10:59, John Bland wrote:
>>>
>>>> Hi,
>>>>
>>>> After our upgrade to DPM 1.8.2 I'm keen to investigate filesystem weights. We have a
>>>>
>>>> dpm-modifyfs --weight weight
>>>>
>>>> option now but no documentation to tell us what values it accepts and how the weights are calculated and used. Anyone have any links to some documentation (or just a one line "here's what the options are")?
>>>>
>>>> Thanks,
>>>>
>>>> John
>>>>
>>>> --
>>>> John Bland [log in to unmask]
>>>> System Administrator office: 220
>>>> High Energy Physics Division tel (int): 42911
>>>> Oliver Lodge Laboratory tel (ext): +44 (0)151 794 2911
>>>> University of Liverpool http://www.liv.ac.uk/physics/hep/
>>>> "I canna change the laws of physics, Captain!"
>>>>
>>>
>>>
>>
>>
>> --
>> John Bland [log in to unmask]
>> System Administrator office: 220
>> High Energy Physics Division tel (int): 42911
>> Oliver Lodge Laboratory tel (ext): +44 (0)151 794 2911
>> University of Liverpool http://www.liv.ac.uk/physics/hep/
>> "I canna change the laws of physics, Captain!"
>>
>
>
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