Hi James, Just checking back -- were you able to test it out with the config option?
Thanks, -venky On Wed, May 7, 2014 at 11:07 PM, Venky Shankar <[email protected]>wrote: > > > > On Wed, May 7, 2014 at 6:10 PM, James Le Cuirot > <[email protected]>wrote: > >> Hello, >> >> I know this has been asked before but I felt that it wasn't fully >> answered and I think the situation may have changed in 3.5. >> >> I have set up geo-replication between two machines on my LAN for >> testing. Both are using NTP and the clocks are definitely in sync. >> CRAWL STATUS reports Changelog Crawl. When I make a change on the >> master, it takes up to a minute (sometimes less) for the slave to >> notice. >> > > That's because the change detection interval is 60 seconds by default[1] > in 3.5. This has been changed to 15 seconds lately. > > >> Now I understand that geo-replication will always have some delay, not >> least because it is asynchronous, but given these are tiny changes with >> practically no other activity going on, I was expecting it to be a >> little more responsive. Even in production, there will very little >> traffic so some additional resource usage to speed things up would not >> be an issue. Is this configurable at all? >> > > It's configurable. Try this: > > # gluster volume set <volume> rollover-time 1 > > to indentify changes (followed by syncing it to the slave) every second. > This will definitely speed up replication. > > > >> >> I've seen it explained previously that inotify does not scale well and >> gluster has taken a more efficient approach. I hadn't expected this to >> come at the cost of such long delays though. We're only planning to >> have two nodes, a master and a slave, and I've also seen it said that >> gluster provides little benefit over a simple periodic call to rsync >> under such setups. Combine that with inotify and the rsync solution >> even starts to look favourable. >> >> Lowering this delay is not a deal-breaker for us, it's just that it >> seems unnecessarily long. I'd appreciate hearing your thoughts. >> > > [1]: > https://github.com/gluster/glusterfs/blob/release-3.5/xlators/features/changelog/src/changelog.c#L1556 > >
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