DRBD tries to ensure data integrity across different computers, and it’s quite good at it. But, as per the old saying Trust, But Verify[1. attributed either to Lenin or Kennedy] it might be a good idea to periodically test whether the nodes really have identical data, similar to the checks that are[1. or at least […]
The sync-rate controller is used for controlling the used bandwidth during resynchronization (not normal replication); it runs in the SyncTarget state, ie. on the (inconsistent) receiver side.
The TL;DR version: don’t use data-integrity-alg in a production setup.
There is quite a bit of confusion about the DRBD configuration value al-extents (activity log extents), so here’s another shot at explaining it.
Similar to the recent post about setting the vm.min_free_kbytes value there’s another sysctl that might improve the behaviour: the dirty ratio.
As briefly mentioned in Pacemaker Explained, DRBD devices need two different values set for their monitor intervals: primitive pacemaker-resource-name ocf:linbit:drbd \ params drbd_resource=”drbd-resource” \ op monitor interval=”61s” role=”Slave” \ op monitor interval=”59s” role=”Master” The reason is that Pacemaker distinguishes monitor operations by their resource and their interval – but not by their role. So, if […]