Table of Contents
This chapter outlines typical administrative tasks encountered during day-to-day operations. It does not cover troubleshooting tasks, these are covered in detail in Chapter 7, Troubleshooting and error recovery.
/proc/drbd is a virtual file
displaying real-time status information about all DRBD
resources currently configured. You may interrogate this
file's contents using this command:
cat /proc/drbd
version: 8.2.4 (api:88/proto:86-88)
GIT-hash: fc00c6e00a1b6039bfcebe37afa3e7e28dbd92fa build by buildsystem@linbit, 2008-01-11 12:44:36
0: cs:Connected st:Secondary/Secondary ds:UpToDate/UpToDate C r---
ns:524288 nr:524288 dw:524288 dr:524288 al:0 bm:64 lo:0 pe:0 ua:0 ap:0
resync: used:0/31 hits:524224 misses:64 starving:0 dirty:0 changed:64
act_log: used:0/257 hits:0 misses:0 starving:0 dirty:0 changed:0
The first line, prefixed with version:, shows
the DRBD version used on your system. The second line contains
information about this specific build.
The other four lines in this example form a block that is
repeated for every DRBD device configured, prefixed by the
device minor number. In this case, this is 0,
corresponding to the device
/dev/drbd0.
The resource-specific output from
/proc/drbd contains various pieces of
information about the resource:
cs(connection state). Status of the network connection. See the section called “Connection states” for details about the various connection states.st(states). Roles of the nodes. The role of the local node is displayed first, followed by the role of the partner node shown after the slash. See the section called “Resource roles” for details about the possible resource roles.![[Note]](images/note.png)
Note For historical reasons, both
/proc/drbdand drbdadm use the ambiguous term “state” when referring to resource roles. That usage is about to fade away; “role” is the preferred term.ds(disk states). State of the hard disks. Prior to the slash the state of the local node is displayed, after the slash the state of the hard disk of the partner node is shown. See the section called “Disk states” for details about the various connection states.ns(network send). Volume of net data sent to the partner via the network connection; in Kibyte.nr(network receive). Volume of net data received by the partner via the network connection; in Kibyte.dw(disk write). Net data written on local hard disk; in Kibyte.dr(disk read). Net data read from local hard disk; in Kibyte.al(activity log). Number of updates of the AL area of the meta data.bm(bit map). Number of updates of the bitmap area of the meta data.lo(local count). Number of open requests to the local I/O sub-system issued by DRBD.pe(pending). Number of requests sent to the partner, but that have not yet been answered by the latter.ua(unacknowledged). Number of requests received by the partner via the network connection, but that have not yet been answered.ap(application pending). Number of block I/O requests forwarded to DRBD, but not yet answered by DRBD.
A resource's connection state can be observed either by
monitoring /proc/drbd, or by issuing the
drbdadm cstate command:
drbdadm cstate resource
Connected
A resource may have one of the following connection states:
StandAlone. No network configuration available. The resource has not yet been connected, or has been administratively disconnected (using drbdadm disconnect), or has dropped its connection due to failed authentication or split brain.Disconnecting. Temporary state during disconnection. The next state is StandAlone.Unconnected. Temporary state, prior to a connection attempt. Possible next states: WFConnection and WFReportParams.Timeout. Temporary state following a timeout in the communication with the peer. Next state: Unconnected.BrokenPipe. Temporary state after the connection to the peer was lost. Next state: Unconnected.NetworkFailure. Temporary state after the connection to the partner was lost. Next state: Unconnected.ProtocolError. Temporary state after the connection to the partner was lost. Next state: Unconnected.TearDown. Temporary state. The peer is closing the connection. Next state: Unconnected.WFConnection. This node is waiting until the peer node becomes visible on the network.WFReportParams. TCP connection has been established, this node waits for the first network packet from the peer.Connected. A DRBD connection has been established, data mirroring is now active. This is the normal state.StartingSyncS. Full synchronization, initiated by the administrator, is just starting. The next possible states are: SyncSource or PausedSyncS.StartingSyncT. Full synchronization, initiated by the administrator, is just starting. Next state: WFSyncUUID.WFBitMapS. Partial resnchronisation is just starting. Next possible states: SyncSource or PausedSyncS.WFBitMapT. Partial resnchronisation is just starting. Next possible state: WFSyncUUID.WFSyncUUID. Synchronization is about to begin. Next possible states: SyncTarget or PausedSyncT.SyncSource. Synchronization is currently running, with the local node being the source of synchronization.SyncTarget. Synchronization is currently running, with the local node being the target of synchronization.PausedSyncS. The local node is the source of an ongoing synchronization, but synchronization is currently paused. This may be due to a dependency on the completion of another synchronization process, or due to synchronization having been manually interrupted by drbdadm pause-sync.PausedSyncT. The local node is the target of an ongoing synchronization, but synchronization is currently paused. This may be due to a dependency on the completion of another synchronization process, or due to synchronization having been manually interrupted by drbdadm pause-sync.VerifyS. On-line device verification is currently running, with the local node being the source of verification.VerifyT. On-line device verification is currently running, with the local node being the target of verification.
A resource's role can
be observed either by monitoring
/proc/drbd, or by issuing the
drbdadm state command:
drbdadm state resource
Primary/Secondary
The local resource role is always displayed first, the remote resource role last.
You may see one of the following resource roles:
Primary. The resource is currently in the primary role, and may be read from and written to. This role only occurs on one of the two nodes, unless dual-primary node is enabled.Secondary. The resource is currently in the secondary role. It normally receives updates from its peer (unless running in disconnected mode), but may neither be read from nor written to. This role may occur on one node or both nodes.Unknown. The resource's role is currently unknown. The local resource role never has this status. It is only displayed for the peer's resource role, and only in disconnected mode.
A resource's disk state can be observed either by
monitoring /proc/drbd, or by issuing the
drbdadm dstate command:
drbdadm dstate resource
UpToDate/UpToDate
The local disk state is always displayed first, the remote disk state last.
Both the local and the remote disk state may be one of the following:
Diskless. No local block device has been assigned to the DRBD driver. This may mean that the resource has never attached to its backing device, that it has been manually detached using drbdadm detach, or that it automatically detached after a lower-level I/O error.Failed. Transient state following an I/O failure report by the local block device. Next state: Diskless.Negotiating. Transient state when an Attach is carried out on an already-connected DRBD device.Inconsistent. The data is inconsistent. This status occurs immediately upon creation of a new resource, on both nodes (before the initial full sync). Also, this status is found in one node (the synchronization target) during synchronization.Outdated. Resource data is consistent, but outdated.DUnknown. This state is used for the peer disk if no network connection is available.Consistent. Consistent data of a node without connection. When the connection is established, it is decided whether the data are UpToDate or Outdated.UpToDate. Consistent, up-to-date state of the data. This is the normal state.