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: > > I have no idea about how long the primary sync its data to secondary? > > Or once the data is changed on primary physical device, it is send to > secondary immediately? Data replication is basically real-time, within the constraints of network bandwidth and raw I/O performance. In the "resource" section of /etc/drbd.conf, you define the transfer protocol to use for that resource (/dev/drbd0 for example). It can be one of the following three: C: write IO is reported as completed, if we know it has reached _both_ local and remote DISK. * for critical transactional data. B: write IO is reported as completed, if it has reached local DISK and remote buffer cache. * for most cases. A: write IO is reported as completed, if it has reached local DISK and local tcp send buffer. (see also sndbuf-size) * for high latency networks If you choose C, then write a file to the DRBD'd filesystem, the write won't return (ie: the command won't complete) until the data is written to both local and remote disks. Mark. -- Mark Watts BSc RHCE MBCS Senior Systems Engineer QinetiQ Trusted Information Management Trusted Solutions and Services Group GPG Key: http://keyserver.veridis.com:11371/search?q=0x455420ED -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: not available URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20070510/c25c904d/attachment.pgp>