[DRBD-user] use drbd on wan

Mia Lueng xiaozunvlg at gmail.com
Tue Sep 20 19:10:24 CEST 2011

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

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

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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