Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 22/12/15 11:11 AM, Mia Lueng wrote: > Hi: > I'm just wondering how secondary handle the write ordering when a same > block is written twice on primary. > > Application submits these updates: X, Y, Z. > They may or may not be to the same block. > If they are to the same block, then the application, file system > or other layer already makes sure (or at least is supposed to do that), > that the first update will finish before the second is submitted. > > These updates are replicated to the peer. > > When X,Y are to the same block, how secondary site make sure that the > first update will finish before the second is summited? > > Thanks. It will always be the same so long as the peer is connected. That is, Primary writes X, change is sent to peer, write is confirmed complete. Primary writes Y (repeat). The only thing that changes is is when the primary considers the write to be complete which depends on your protocol (c == hits storage on the peer, b == received on the peer's network, a == hits the local machines network stack). -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education?