[DRBD-user] Moving TeraBytes to drbd device

Digimer lists at alteeve.ca
Thu Oct 5 23:58:25 CEST 2017

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Good fencing prevents split-brains, period. Setup pacemaker, setup and
test stonith, configure DRBD to use 'fencing resource-and-stonith;' and
enable the crm-{un,}fence-peer.sh' {un,}fence-handlers. The setup
pacemaker to colocate the DRBD resource -> FS -> IP.

digimer

On 2017-10-05 05:01 PM, José Andrés Matamoros Guevara wrote:
> Don't know yet. Thinking about using pacemaker, for high availability. But have a manually recovery to avoid split brain - corruption data situations. Maybe we are going to use three-four servers to have a disaster recovery site.
> 
> Andres.
> 
> -----Original Message-----
> From: Digimer [mailto:lists at alteeve.ca] 
> Sent: Thursday, 5 October, 2017 12:43 PM
> To: José Andrés Matamoros Guevara <amatamoros at ie.com.sv>; drbd-user at lists.linbit.com
> Subject: Re: [DRBD-user] Moving TeraBytes to drbd device
> 
> Will you be using pacemaker for auto-recovery, or are you planning to do fully manual recovery?
> 
> digimer
> 
> On 2017-10-05 12:19 PM, José Andrés Matamoros Guevara wrote:
>> OK. That's a procedure I have thought about, but didn't know if there were another more effective. I just have to check how much data I have to sync during the window.
>>
>> Last question: what kind of test do you recommend to check the new drbd system? I have configure a few systems but never this important.
>>
>> Thanks again,
>>
>> Andres.
>>
>>
>> -----Original Message-----
>> From: Digimer [mailto:lists at alteeve.ca]
>> Sent: Wednesday, 4 October, 2017 11:11 PM
>> To: José Andrés Matamoros Guevara <amatamoros at ie.com.sv>; 
>> drbd-user at lists.linbit.com
>> Subject: Re: [DRBD-user] Moving TeraBytes to drbd device
>>
>> If it were up to me, given what I understand of your requirements (which is minimal), I'd look at setting up the new DRBD system. Test it carefully and when ready, do an rsync to get the bulk data over. When your windows opens, re-run the rsync to copy just what's changed.
>>
>> If you're asking how to setup a DRBD based system, we'll need to know more about what you want the system to do.
>>
>> cheers,
>>
>> digimer
>>
>> On 2017-10-04 11:29 PM, José Andrés Matamoros Guevara wrote:
>>> Thanks for your answer.
>>>
>>> Yes, I need to copy a SAN to a new drbd system. And yes, I'll check 
>>> with LinBit for support if I don't find a safe solution for myself.
>>>
>>> Just a question: I have been looking through the LinBit documents and 
>>> haven't found exactly what I was looking for. If you can point me 
>>> about what document/documents or topics I have to read about, will be great.
>>>
>>> Thanks for the info.
>>>
>>> Andres. 
>>>
>>> -----Original Message-----
>>> From: Digimer [mailto:lists at alteeve.ca]
>>> Sent: Tuesday, 3 October, 2017 6:10 PM
>>> To: José Andrés Matamoros Guevara <amatamoros at ie.com.sv>; 
>>> drbd-user at lists.linbit.com
>>> Subject: Re: [DRBD-user] Moving TeraBytes to drbd device
>>>
>>> On 2017-10-03 06:57 PM, José Andrés Matamoros Guevara wrote:
>>>> I have been consulted about moving multiple Terabytes to a new 
>>>> system using drbd to ensure high availability. I have been thinking 
>>>> on multiple scenarios to move the data as fast as I can and to have 
>>>> a minimal maintenance window to change the systems.
>>>>
>>>> Is there any how-to or recommendation about it? I know it is not 
>>>> exactly a drbd consult but I supposed you have been using it for a 
>>>> while and have more idea about a best practice. I have thought to 
>>>> have a backup program to copy the data and then update it during the 
>>>> maintenance window, but been lots of TB, the reading/writing data 
>>>> time is going to be the factor to consider.
>>>>
>>>> Thanks in advance and best regards, Andres.
>>>
>>> The best answer is to engage LINBIT for commercial support if you've 
>>> been tasked with a sensitive project and a minimal window to do it in.
>>>
>>> That said, I'll share what comes to mind;
>>>
>>> If you mean "move" as in "copy the data to a new system that already 
>>> has DRBD configured and tested", then it is merely a question of hardware.
>>> Make sure you have a sufficiently fast new system to accept the 
>>> incoming volume of data within the prescribed time frame. DRBD itself 
>>> has minimal overhead, so it is really a question of the speed of the 
>>> disks and the replication link.
>>>
>>> If you mean to convert an existing filesystem on existing hardware to 
>>> be backed by DRBD, then you need to either grow the backing storage 
>>> by ~32MiB per TiB of existing data, or setup a matching sized storage 
>>> device and configure external metadata. With that extra space, you 
>>> can setup DRBD and it will see the existing FS and data fine. You'll 
>>> need a full resync to the new peer, of course. Also, test/practice 
>>> outside prod thoroughly to be certain you have the steps down pat.
>>>
>>> There are docs on how to do this openly available on LINBIT's website.
>>> If you get stuck on certain steps, post specific questions and we'll help.
>>>
>>> --
>>> Digimer
>>> Papers and Projects: https://alteeve.com/w/ "I am, somehow, less 
>>> interested in the weight and convolutions of Einstein’s brain than in 
>>> the near certainty that people of equal talent have lived and died in 
>>> cotton fields and sweatshops." - Stephen Jay Gould
>>>
>>
>>
>> --
>> Digimer
>> Papers and Projects: https://alteeve.com/w/ "I am, somehow, less 
>> interested in the weight and convolutions of Einstein’s brain than in 
>> the near certainty that people of equal talent have lived and died in 
>> cotton fields and sweatshops." - Stephen Jay Gould
>>
> 
> 
> --
> Digimer
> Papers and Projects: https://alteeve.com/w/ "I am, somehow, less interested in the weight and convolutions of Einstein’s brain than in the near certainty that people of equal talent have lived and died in cotton fields and sweatshops." - Stephen Jay Gould
> 


-- 
Digimer
Papers and Projects: https://alteeve.com/w/
"I am, somehow, less interested in the weight and convolutions of
Einstein’s brain than in the near certainty that people of equal talent
have lived and died in cotton fields and sweatshops." - Stephen Jay Gould



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