[Gluster-devel] LVM

[Anand Babu Periasamy]

Towards end of this year, we will be introducing snapshot, hsm, dedup ... as GlusterFS
translators. It is better to wait for that one. Until then, Amanda like backup solution
over mounted GlusterFS volume is a better approach.
--
Anand Babu Periasamy
GPG Key ID: 0x62E15A31
Blog [http://ab.freeshell.org]
The GNU Operating System [http://www.gnu.org]
Z RESEARCH Inc [http://www.zresearch.com]



Onyx wrote:
> Krishna Srinivas wrote:
>> Onyx,
>>
>> Just thinking about it, using snapshots as glusterfs storage volumes
>> is not advisable unless you know what you are doing. If you roll back
>> a volume, it will depend on how selfheal of unify/afr handle it. AFR
>> would just update the rolled back volume with the other copy.
>>   
> Yes, that was what I was thinking. Newer will overwrite the older, witch 
> is the rolled-back one in this case.
> 
>> Better use of LVM + glusterfs would be to grow the backend FS
>> as an when needed.
>>   
> Yes I have been thinking of that too.
> I was just  'brainstorming' on a solution to have snapshot features in 
> glusterfs.
> 
>> I think use case of snapshots just in backend LVM in a glusterfs
>> environment will not be much. However snapshots in a glusterfs
>> as a whole filesystem will be useful.
>>   
> It surely would.
> Now, what if I would setup a glusterfs volume with lvm on all it's 
> subvolumes. It shouldn't be to hard to write something that, if I want 
> to make a snapshot of the whole glusterfs filesystem, it sends my "take 
> snapshot"-command to the all the lvm subvolumes and executes the actual 
> lvm snapshot command over there. Or am I missing something here?
> 
> 
> 
>> Krishna
>>
>> On Sat, Jun 14, 2008 at 4:13 PM, Onyx <lists at bmail.be> wrote:
>>  
>>> Hmm, yes, what was I thinking....
>>>
>>> But if I want to use LVM snapshots underneath glusterfs volumes (on
>>> different bricks) who are then unified or afr'd,  won't there be a 
>>> problem
>>> because the snapshots aren't taken at exactly the same time? Or what 
>>> would
>>> be the expected behavior if I for example roll back one volume in an afr
>>> setup and not the other?
>>>
>>>
>>>
>>>
>>>
>>> Anand Babu Periasamy wrote:
>>>    
>>>> -- 
>>>> Anand Babu Periasamy
>>>> GPG Key ID: 0x62E15A31
>>>> Blog [http://ab.freeshell.org]
>>>> The GNU Operating System [http://www.gnu.org]
>>>> Z RESEARCH Inc [http://www.zresearch.com]
>>>>
>>>> Hi Onyx,
>>>> GlusterFS volumes are file based. LVM requires block based
>>>> store. You cannot have LVM over GlusterFS. I am assuming
>>>> you are asking about GlusterFS over LVM. You can use LVM and
>>>> its snapshotting ability underneath the GlusterFS posix volume.
>>>> It will work transparently.
>>>>
>>>> -- 
>>>> Anand Babu Periasamy
>>>> GPG Key ID: 0x62E15A31
>>>> Blog [http://ab.freeshell.org]
>>>> The GNU Operating System [http://www.gnu.org]
>>>> Z RESEARCH Inc [http://www.zresearch.com]
>>>>
>>>>
>>>>
>>>> Onyx wrote:
>>>>      
>>>>> Has anyone ever tested LVM on top of a glusterfs volume? Would this 
>>>>> even
>>>>> be possible?
>>>>> I'm interested because of the snapshot feature of LVM.
>>>>>
>>>>> Thanks!
>>>>>
>>>>>
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>>>
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>>>     
> 
> 
> 
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