[DRBD-user] use drbd on wan

Mia Lueng xiaozunvlg at gmail.com
Wed Sep 21 08:32:54 CEST 2011


And I need confirm this:
1. when I connect a disconnected drbd resource, the resource will
perform a quick sync
2. The quick sync will keep the data order and provide data integration.

2011/9/21 Andy Jewell <Andy.Jewell at sysmicro.co.uk>:
> Wouldn't it be better to run in asynchronous mode so your writes on
> the master don't block while the data is shipped to the secondary?
> There's obviously a trade-off with coherency on the secondary but you
> don't have the latency.
>
> Sent from my iPhone
>
> On 20 Sep 2011, at 18:18, "Mia Lueng" <xiaozunvlg at gmail.com> wrote:
>
>> HI All:
>>
>> In our case, we use drbd to sync oracle db data in two node across the
>> wan. Since the net bandwidth is slow(<2M), the i/o performance is
>> pretty poor in primary node because i/o operation will be pending to
>> wait the data transmission.
>> So we have considered  the following solution:  On secondary node,
>> run disconnect and connect command in sequence . Diconnect drbd0 ,
>> wait 5 minutes (or longer time), connect drbd0 again, and after sync
>> complete , disconnect drbd0 again. But we are wondering the follow
>> issues:
>>
>> 1. How can we confirm that each sychorinzation after connecting is a
>> quick sync and not a full sync? And how to tune it to be that.
>> 2. the secondary node disconnect drbd0 only when the cstate is
>> Connected and dstate is UptoDate. Can  the data integration of db data
>> be guaranteed?  In other words, If the primary node crash at this
>> moment,  the oracle db can be started on the secondary node?  And in
>> quich sync , Is the data written on secondary node  in the same order
>> as  it written on primary node ?
>> 3. is the activity log size tuning helpful for this situation?
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>


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