Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Thu, Oct 22, 2015 at 01:03:10AM -0400, Digimer wrote: > On 21/10/15 03:57 PM, Christian Völker wrote: > > Hi all, > > > > just a simple question for my own curiosity. > > > > Assume a two node master-slave setup. Disk on the master fails. All > > reads and writes go through the slave (master remains primary). > > > > Now the disk on the primary is replaced and the full sync is started. > > > > Now let's say the sync is at 40% and a write occurs which fits into the > > not yet synced 60% of the disk. > > > > Ist the block now written in parallel to both nodes and marked on the > > primary as "already synced" or does the write affect only the slave and > > during the remaining sync the block is copied back to the primary? > > > > Just curious.... > > > > Thanks! > > > > Chrischan > > Once connected, all new writes are synchronous, yes. Out of sync blocks > replicate at the resync rate. This is why setting a high resync rate > will slow down applications writing to DRBD because the bandwidth > available for new writes is total capacity minus capacity used by resync. But yes, any write during resync to no-yet synced, "dirty" blocks will bring those blocks in sync as well. As an extreme example, if you'd just zero-out the full device during resync, you'd bring it in-sync by application writes. -- : Lars Ellenberg : http://www.LINBIT.com | Your Way to High Availability : DRBD, Linux-HA and Pacemaker support and consulting DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. __ please don't Cc me, but send to list -- I'm subscribed