Tim-- I think the short answer is no difference, and yes it will resync. When your nodes become disconnected, there is a "replay of the changes" when they reconnect -- a resync operation. This page describes it:
http://drbd.linbit.com/users-guide-emb/s-quick-sync-bitmap.html However, important note -- and this would be the same with both A and C protocols -- that resync is done from "front to back" of the block device, not in time/date order. So for the duration of that resync operation, your secondary will be in an inconsistent state. (Same goes for the write-ahead mode. Use with caution!!) As you noted, the main difference between A and C is if / when your primary node fails in some spectacular fashion (e.g. it blows up) you will lose acknowledged writes. (Which is usually very bad.) Warm Regards, OLW -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Timofey Koolin Sent: Friday, April 24, 2015 3:57 AM To: [email protected] Subject: [DRBD-user] Data corruption risk in protocol A,C. Is protocol A and C difference by data corruption risk? I mean long time corruption when I have WAN replication with non ideal connections. Connection may be broken from time to time. Now I use protocol C. But I want to change it to protocol A. I know about lost few last operations when I lost master node - it is OK. I want to know - Has protocol A more data corruption risk then protocol C or not during replication. For example: 1. Write "123" to Master 2. Put data to tcp buffer in master, master return OK write data to OS. 3. Lost connection before data really send and accept by slave. Will "123" put to slave after reconnect during resync process? _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user -------------------------------------------------------------------------------------------------------------------------------------------------------------- This e-mail and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this e-mail in error please notify the sender immediately and delete this e-mail from your system. Please note that any views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of Ricardo (save for reports and other documentation formally approved and signed for release to the intended recipient). Only Ricardo's authorized representatives may enter into legally binding obligations on behalf of Ricardo. Ricardo may monitor outgoing and incoming e-mails and other telecommunications systems. By replying to this e-mail you give consent to such monitoring. The recipient should check e-mail and any attachments for the presence of viruses. Ricardo accepts no liability for any damage caused by any virus transmitted by this e-mail. "Ricardo" means Ricardo Inc. and its affiliated companies. --------------------------------------------------------------------------------------------------------------------------------------------------------------'. _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user
