[Lustre-discuss] lfs setstripe

[Brock Palen]

On Apr 17, 2008, at 10:48 PM, Kaizaad Bilimorya wrote:
>
> On Thu, 17 Apr 2008, Brock Palen wrote:
>> I don't think you need to do this.
>> If i understand right, you can set the stripe size of the mount,  
>> and everything inside that directory inherits it, unless they them  
>> self's were explicitly set.
>
> Hi Brock, thanks for the reply.
>
> I have set the stripe count on the lustre mount using "lfs  
> setstripe" but the problem is that any sub directories that already  
> existed under this mount will have the default filesystem stripe  
> count and not the new one I set, so any new files created under  
> these existent sub directories will inherit their parent directory  
> stripe count and not the newly set one from the lustre mount.

Ahh I see, I really don't know, I think try walking the system and  
changing all the old directories.  I have not had to do this my self.

>
> eg:
>
> /lustremount -> "lfs setstripe /lustremount 0 -1 2"
> /lustremount/existing_dir -> has filesystem default stripe count (1  
> in this case)
> /lustremount/new_dir -> gets stripe count of parent (2 in this case)
> /lustremount/existing_dir/newfile -> has filesystem default stripe  
> count of 1
>
> So that is why I have to do either option 1 (change default) or 2  
> (traverse and set explicitly for all existing dirs) that I  
> specified, but I would like to know if there are any performance or  
> other reasons not to do option 2.
>
> thanks
> -k
>
>> Also files that already are created will keep the stripe settings  
>> they were created with.  You would need to copy them, and move  
>> over the old one to change to the new stripe settings.  Check the  
>> lustre manual they have something about this.
>>
>> On Apr 17, 2008, at 10:34 AM, Kaizaad Bilimorya wrote:
>>> Hello,
>>> I would like to adjust the stripe count for our lustre  
>>> filesystem. Would
>>> it be better to:
>>> 1) Kill all jobs, unmount the lustre filesystem from all clients,  
>>> and then
>>>     adjust the default stripe count for the lustre filesystem on  
>>> the MDS
>>>     using lctl.
>>> or
>>> 2) Use "find" and the "lfs setstripe" command to traverse and set  
>>> the
>>>     stripe count for all directories in a currently mounted lustre
>>>     filesystem.
>>> Besides the traversal cost of the filesystem, are there other
>>> disadvantages, performance reasons, or other reasons not to use  
>>> option 2?
>>> thanks
>>> -k
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>>> Lustre-discuss at lists.lustre.org
>>> http://lists.lustre.org/mailman/listinfo/lustre-discuss
>>
>
>