drbd storage driver¶
Drbd is a Linux kernel driver presenting shared block devices from pairs of local block devices. Replication data goes over the network and can be synchronous ou near-synchronous. It supports the active-active or active-passive operation modes. The former being a prerequisite for cluster filesystem.
OpenSVC drbd driver has provisioning capabilities.
OpenSVC also includes a drbd pool driver, to automatically provision drbd-replicated volumes from a volume group, a zpool or a directory.
The drbd resource configuration is expected to reside in
If a vg is layered above drbd, a specific LVM configuration is recommended (link)
Set write_cache_state = 0 in /etc/lvm/lvm.conf Remove /etc/lvm/cache/.cache
Files contributed to sync#i0¶
This file is thus replicated from the node running the service to the other nodes and drpnodes.
The drbd driver is a member of the ‘disk group’ class.
Promote to ‘primary’ state
Demote to ‘secondary’ state
Demote to ‘unconfigured’ state
[disk#1] type = lv name = lv1 vg = vg1 size = 190m standby = true [disk#2] type = drbd res = res1 disk = /dev/vg1/lv1 standby = true
The drbd and underlying logical volume resources must be configured for standby=true. This make sure the lv is available for drbd on the slave nodes and the drbd is in secondary state.
The logical volume resource id (disk#1) is sorted before the drbd resource id (disk#2), so the logical volume starts before the drbd.