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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