The documentation for DPM is here: https://svnweb.cern.ch/trac/lcgdm/wiki/Dpm
(although the command documentation still hasn't been ported to the
trac, and so is a bit... crufty) for future reference.
Some of the commands I mentioned are DPM toolkit commands, which are
documented here: https://www.gridpp.ac.uk/wiki/DPM-admin-tools
(I'm the developer of these, so do bother me with requests)
Sam
On 3 August 2012 15:46, John Hill <[log in to unmask]> wrote:
> Thanks for this - sorry for sounding grouchy earlier, but it has been a
> particularly frustrating day...
>
> John
>
>
> On 03/08/2012 15:25, Sam Skipsey wrote:
>>
>> Okay:
>>
>> So, dpns-ls lists the entries in the DPNS namespace.
>> This is not the same as the physical file namespace (and indeed,
>> shouldn't be - since replicas work by having multiple physical files
>> behind a single DPNS filename).
>>
>> dpm-list-disk lists all of the physical filenames known about by DPM
>> for a given disk (and filesystem).
>>
>> dpm-disk-to-dpns does that, and also gives you the locations in the
>> DPNS namespace for all of those files.
>>
>> dpm-delreplica lets you delete a specific replica (that is: a
>> particular physical file path, not a DPNS entry) from DPM.
>>
>> You probably want to use dpm-delreplica if you know that there are
>> multiple replicas of a file.
>> (If you don't then you probably want to try rfrm, to use the
>> lower-level rfio interface to remove the file, or dpns-rm (optionally
>> with the -f force option) to remove the DPNS entry for the file -
>> which means that DPM will no longer know about it.)
>>
>> Sam
>>
>>
>> On 3 August 2012 15:16, John Hill <[log in to unmask]> wrote:
>>>
>>> On 03/08/2012 13:49, Sam Skipsey wrote:
>>>>
>>>>
>>>> On 3 August 2012 13:38, Ewan MacMahon <[log in to unmask]>
>>>> wrote:
>>>>>>
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Testbed Support for GridPP member institutes [mailto:TB-
>>>>>> [log in to unmask]] On Behalf Of John Hill
>>>>>>
>>>>>> I thought dpns-rm was the right tool, but when I tried it on one
>>>>>> of
>>>>>> the files I'm trying to remove I got a "File Exists" message, which
>>>>>> confused me sufficiently to make me think that it wasn't trying to do
>>>>>> the
>>>>>> correct thing. At least I now know I'm on the right track.
>>>>>>
>>>>> I think we usually wind up using rfrm for this, so the basic
>>>>> sequence of events is to use dpm-disk-to-dpns to get a list of
>>>>> everything that used to be on the dead filesystem, then split
>>>>> the lines in that output to give you just a list of the DPNS
>>>>> names (it gives you the filesystem paths as well), then rfrm
>>>>> the files by DPNS name. I have a vague recollection of doing
>>>>> something properly handle files that have multiple replicas,
>>>>> but I've just been looking for the details of that and haven't
>>>>> found it yet.
>>>>>
>>>>
>>>> I'm fairly sure I did write something to do this.
>>>> (For multiple replicas, dpns-delreplica should work, if you know which
>>>> replica you want to remove, as it was written for this by Greig.)
>>>>
>>>> Sam
>>>>
>>>>> Ewan
>>>
>>>
>>>
>>> The background to this is that I need to remove the DPNS entries for my
>>> failed diskserver - I think that just means deleting the particular
>>> replica
>>> which is lost. I would have thought that dpns-ls was the right tool, but
>>> then I'm finding that understanding how to do things in GRID Management
>>> makes reading the Rosetta Stone look like light relaxation.
>>>
>>> John
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