Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Tue, 06 Mar 2012 11:40:22 +0100, Felix Frank <ff at mpexnet.de> wrote: > Hi, > > On 03/06/2012 11:34 AM, Kaloyan Kovachev wrote: >> Yes. You may use floating IP for DRBD and have one instance (IP) in site >> A >> and another in site B for each service. >> Do not use the service IP as floating IP as you will have problems moving >> the service from A to B. >> >> If A1 is active, you have the DRBD_A1 IP on that node, wich will move to >> A3 in case of failure before the service ... now you have DRBD_A1 and the >> service running on A3 over DRBD_A1, while DRBD_B1 will run undependable >> on >> B1 or B3. >> Now your A site goes down - you promote DRBD_B1 to primary and start A1 >> service on B1 over DRBD_B1. > > interesting. So you suggest that A1 should DRBD-sync with B1 at all > times etc.? Yes. That's the only option to sync both SAN's if they do not provide such functionality. > > Keep in mind that this is shared storage we're talking about here, no > local disks in either A1 *or* B1. I believe DRBD could be made to > operate thus, but there might be performance issues. Again Yes. Performance will be lower and protocol A with DRBD Proxy may be required, but again if the SAN does not provide native cross-site replication, there is not much else to do ... rsync from a snapshot is one i can think of, but even from the currently inactive node (A3) the performance will suffer and additionally there will be delay in synchronization and possible data loss, so DRBD is still better. > > Cheers, > Felix