[DRBD-user] how can i reduce the time doing initial full sync

Sebastian Riemer sebastian.riemer at profitbricks.com
Tue Jul 31 13:06:30 CEST 2012

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On 31.07.2012 12:14, David Coulson wrote:
> Does it matter? Your data is accessible from both nodes while it syncs.
> I suppose you have a risk of the primary failing until it has a full
> copy on the other node, but since it is a one time, on build, thing it
> isn't a big deal.
> Short answer is bigger pipe, faster drives, plenty of cpu. And more
> pipe. And make sure your configured syncer rate is enough to fully
> utilize your connectivity between nodes.

To add one thing here: DRBD should stop using very slow 4 KiB IO
requests for syncer stuff. You can see that with blktrace/blkparse.
Full-size 512 KiB IO requests should be used instead.
Only fools add hardware to fix a software issue.

I've analyzed the DRBD kernel code recently for a customer:

Btw.: The default syncer rate limit of 10 MB/s is also quite outdated.


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