Should match exactly the output of
uname -n
Device:
The device node to use: /dev/drbd0 - DRBD block device.
Address, Port:
The inet address and port to bind to locally, or to connect to the partner node.
Meta-disk:
The disks to store meta data. DRBD allows you to either place its meta data on the same backing device where it puts the actual usable production data (internal meta data), or on a separate block device (external meta data). I have allocated 128 MB for meta data on a external meta data block device. However you may concern table given below to estimate meta data sizes
| Block device size |
DRBD meta data |
| 1 GB |
2 MB |
| 100 GB |
5 MB |
| 1 TB |
33 MB |
| 4 TB |
128 MB |
Incon-degr-cmd:
What should be done in case the cluster starts up in degraded mode, but knows it has inconsistent data (the lower level device reports io-error).
on-io-error detach:
If the lower level device reports io-error, the node drops its backing storage device and continues in diskless mode.
degr-wfc-timeout:
Wait for connection time out, if this node was a degraded cluster. This is used instead of wfc-timeout (wait for cluster time out).
Syncer:
Limit the bandwidth used by the resynchronization process.
group:
All devices in one group are resynchronized parallel. Resynchronization of groups is serialized in ascending order.
Al-extents:
Automatically performs hot area detection. With this parameter you control how big the hot area can get. Each extent marks 4M of the backing storage (=low level device). In case a primary node leaves the cluster unexpectedly the areas covered by the active set must be resynced upon rejoin of the failed node. The data structure is stored in the meta-data area, therefore each change of active set is a write operation to meta-data device. A higher number of extents gives longer resync times but less updates to the meta-data.
The Do And Don't:
Do not attempt to mount a DRBD in secondary state. Once you set up DRBD never bypass it or access the underlying device directly!
요점은......
※ DRBD는 MASTER의 쓰기 동작이 완료되는 시점에 SLAVE에 네트워크로 데이타가 전송되며 기록합니다.
※ 블록장치 크기에 따라서 meta data 크기를 생성하면 됩니다.
| Block device size |
DRBD meta data |
| 1 GB |
2 MB |
| 100 GB |
5 MB |
| 1 TB |
33 MB |
| 4 TB |
128 MB |
