Jul 182007
 

Sun Cluster Set up

  • don’t mix PCI and SBus SCSI devices

Quorum Device Rules

  • A quorum device must be available to both nodes in a 2-node cluster
  • QD info is maintained globally in the CCR db
  • QD should contain user data
  • Max and optimal number of votes contributed by QDs must be N -1
    • (where N == number of nodes in the cluster)
  • If # of QDs >= # of nodes, Cluster cannot come up easily if there are too

    • many failed/errored QDs.
  • QDs are not required in clusters with more than 2 nodes, but recommended
    • for higher cluster availability.
  • QDs are manually configured after Sun Cluster s/w installation is done.
  • QDs are configured using DID devices

Quorum Math and Consequences

  • A running cluster is always aware of (Math):
    • –> Total possible Q votes (number of nodes + disk quorum votes) –> Total present Q votes (number of booted nodes + available QD votes) –> Total needed Q votes ( >= 50% of possible votes)

    Consequences:

    • –> Node that cannot find adequate Q votes will freeze, waiting for

      • other nodes to join the cluster

      –> Node that is booted in the cluster but can no longer find the

      • needed number of votes kernel panics

installmode Flag — allows for cluster nodes to be rebooted after/during initial

  • installation without causing the other (active) node(s) to panic.

Cluster status

# Reporting the clsuter membership and quorum vote information

# /usr/cluster/bin/scstat -q

Verifying cluster configuration info

# scconf -p

Run scsetup to correct any configuration mistakes and/or to:

* add or remove quorum disks * add, remove, enable, disable cluster transport components * register/unregister vxVM dgs * add/remove node access from a VxVM dg * change clsuter private host names * change cluster name

Shutting down cluster on all nodes:

# scshutdown -y g 15

# scstat (verifies cluster status)

Cluster Daemons

<span style="font-size:85%;">lahirdx@aescib1:/home/../lahirdx > ps -ef|grep cluster|grep -v grep<br /></span><span style="font-size:85%;">    root     4     0  0   May 07 ?       352:39 cluster<br /></span><span style="font-size:85%;">    root   111     1  0   May 07 ?        0:00 /usr/cluster/lib/sc/qd_userd<br /></span><span style="font-size:85%;">    root   120     1  0   May 07 ?        0:00 /usr/cluster/lib/sc/failfastd<br /></span><span style="font-size:85%;">    root   123     1  0   May 07 ?        0:00 /usr/cluster/lib/sc/clexecd<br /></span><span style="font-size:85%;">    root   124   123  0   May 07 ?        0:00 /usr/cluster/lib/sc/clexecd<br /></span><span style="font-size:85%;">    root  1183     1  0   May 07 ?       46:45 /usr/cluster/lib/sc/rgmd<br /></span><span style="font-size:85%;">    root  1154     1  0   May 07 ?        0:07 /usr/cluster/lib/sc/rpc.fed<br /></span><span style="font-size:85%;">    root  1125     1  0   May 07 ?       23:49 /usr/cluster/lib/sc/sparcv9/rpc.pmfd<br /></span><span style="font-size:85%;">    root  1153     1  0   May 07 ?        0:03 /usr/cluster/lib/sc/cl_eventd<br /></span><span style="font-size:85%;">    root  1152     1  0   May 07 ?        0:04 /usr/cluster/lib/sc/cl_eventlogd<br /></span><span style="font-size:85%;">    root  1336     1  0   May 07 ?        2:17 /var/cluster/spm/bin/scguieventd -d<br /></span><span style="font-size:85%;"><br /></span><span style="font-size:85%;">    root  1174     1  0   May 07 ?        0:03 /usr/cluster/bin/pnmd<br /></span><span style="font-size:85%;">    root  1330     1  0   May 07 ?        0:01 /usr/cluster/lib/sc/scdpmd<br /></span><span style="font-size:85%;">    root  1339     1  0   May 07 ?        0:00 /usr/cluster/lib/sc/cl_ccrad<br /><br /></span>
  • FF Panic rule — failfast will shutdown the node (panic the kernel) if specified daemon is not restarted within 30s.
  • cluster — system proc created by the kernel to encap kernel threads that make up the core kernel range of operatiosn. It directly panics the kernel if it’s sent a KILL signal (SIGKILL). Other signals have no effect.
  • clexecd — this is used by cluster kernel threads to execure userland cmds (such as run_reserve and dofsck cmds). It is also used to run cluster cmds remotely (eg: scshutdown).A failfast driver panics the kernel if this daemon is killed and not restarted in 30s.
  • cl_eventd — This daemon registers and forwards cluster events s(eg: nodes entering and leaving the cluster). With a min of SC 3.1 10/03, user apps can register themselves to receive cluster events. The daemon automatically get’s respawned by rpc.pmfd if it is killed.
  • rgmd — This is the resource group mgr, which manages the state of all cluster-unaware applications. A failfast driver panics the kernel if this daemon is killed by not started in 30s.
  • rpc.fed — this is the “fork-and-exec” daemon – -which handles reqs from rgmd to spawn methods for specific data services. failfast will hose the box if this is killed and not restarted in 30s.
  • scguieventd — this daemon processes cluster events for the SunPlex Mgr GUI, so that the display can be updated in real time. It’s not automatically started if it stops. If you are having trouble with SunPlex Mgr, might have to restart the daemon or reboot the specific node.

  • rpc.pmfd — This is the process monitoring facility. It is i used as a general mech to initiate restarts and failure action scripts for some cluster f/w daemons, and for most app daemons and app fault monitors. FF panic rule holds good.
  • pnmd — This is the public Network mgt daemon, and manages n/w status info received from the local IPMP (in.mpathd) running on each node in the cluster. It is automatically restarted by rpc.pmfd if it dies.
  • scdpmd — multi-threaded DPM daemon runs on each node. DPM daemon is started by an rc script when a node boots. It montiors the availability of logical path that is visible thru various multipath drivers (MPxIO), HDLM, Powerpath, etc. Automatically restarted by rpc.pmfd if it dies.

Validating basic cluster config

  • The sccheck (/usr/cluster/bin/sccheck) cmd validates the cluster configuration:
  • /var/cluster/sccheck is the repository where it stores the reports generated.

Disk Path Monitoring

  • scdpm -p all:all #prints all disk paths in the clsuter and their status

    scinstall -pv #check the clsuter installation status -- package revisions, patches applied, etc

  • Cluster release file: /etc/cluster/release

Shutting down cluster

  • scshutdown -y -g 30

Booting nodes in non-cluster mode
  • <span style="font-size:85%;">        boot -x<br /></span><span style="font-size:85%;">    </span>

Placing node in maintenance mode
  • scconf -c -q node=,maintstate

Reset the maintenance mode by rebooting the node or running
  • scconf -c -q reset By placing a node in a cluster in maintenance mode, we reduce the number of reqd. quorum votes and ensuring that cluster operation is not disrupted as a result thereof).

    Sunplex manager is available on https::3000

VxVM Rootdg requirements for Sun Cluster

* vxio major number has to be identical on all nodes of the cluster (check for vxio entry in /etc/name_to_major)

* vxvm installed on all nodes physically connected to shared storage — on non-storage nodes, yvxvm can be used to encapsulate and mirror the boot disk. If not using VxVM on a non-storage node, use SVM. All is required in such a case is the vxio major number be identical to all other nodes of the cluster (add an entry in /etc/name_to_major file).

* VxVM license is reqd. on all nodes not connected to a A5x00 storedge array.

* Std rootdg created on all nodes where vxVM is installed. Options to initialize rootdg on each node are:

  • –> Encap boot disk so it can be mirroered. Preserve all data and creating volumes inside rootdg to encap /global/.devices/node@# –> If disk has more than 5 slices on it, it cannot be encap’ed. –> Initialize other local disks into rootdg.

* Unique volume name and minor number across the nodes for the /global/.devices/node@# file system if the boot disk is encap’ed — the /global/.devices/node@# fs must be on devices with a unique name on each node, because it’s mounted on each node for the same reason. The normal Solaris OS /etc/mnttab logic redates global fs and still demands that each device have a unique major/minor number. VxVM doesn’t support changing minor numbers of individual volumes. The entire disk group has to be re-minored.

Use the following command:

<span style="font-size:85%;">#vxdg  [ -g diskgroup ] [ -f ]  reminor<br /></span><span style="font-size:85%;">           [diskgroup ]  new-base-minor<br /></span>

From the vxdg man pages:

<span style="font-size:85%;">     reminor   Changes the base minor number for  a  disk  group,<br /></span><span style="font-size:85%;">               and  renumbers  all devices in the disk group to a<br /></span><span style="font-size:85%;">               range starting at that number.  If the device  for<br /></span><span style="font-size:85%;">               a  volume  is  open,  then  the  old device number<br /></span><span style="font-size:85%;">               remains in effect until the system is rebooted  or<br /></span><span style="font-size:85%;">               until  the disk group is deported and re-imported.<br /></span><span style="font-size:85%;">               Also, if you close an open volume, then  the  user<br /></span><span style="font-size:85%;">               can   execute  vxdg reminor  again  to  cause  the<br /></span><span style="font-size:85%;">               renumbering to take effect  without  rebooting  or<br /></span><span style="font-size:85%;">               reimporting.<br /></span><span style="font-size:85%;"><br /></span><span style="font-size:85%;">               A new device number may also overlap with  a  tem-<br /></span><span style="font-size:85%;">               porary  renumbering for a volume device. This also<br /></span><span style="font-size:85%;">               requires a reboot or reimport for the  new  device<br /></span><span style="font-size:85%;">               numbering to take effect.  A temporary renumbering<br /></span><span style="font-size:85%;">               can happen in the following situations:  when  two<br /></span><span style="font-size:85%;">               volumes  (for  example,  volumes  in two different<br /></span><span style="font-size:85%;">               disk groups) share the same  permanently  assigned<br /></span><span style="font-size:85%;">               device number, in which case one of the volumes is<br /></span><span style="font-size:85%;">               renumbered temporarily to use an alternate  device<br /></span><span style="font-size:85%;">               number; or when the persistent device number for a<br /></span><span style="font-size:85%;">               volume was changed, but the active  device  number<br /></span><span style="font-size:85%;">               could  not be changed to match.  The active number<br /></span><span style="font-size:85%;">               may be left unchanged after  a  persistent  device<br /></span><span style="font-size:85%;">               number change either because the volume device was<br /></span><span style="font-size:85%;">               open, or because the new number was in use as  the<br /></span><span style="font-size:85%;">               active device number for another volume.<br /></span><span style="font-size:85%;"><br /></span><span style="font-size:85%;">               vxdg fails if you try to use a  range  of  numbers<br /></span><span style="font-size:85%;">               that  is  currently  in use as a persistent (not a<br /></span><span style="font-size:85%;">               temporary) device number.  You can  force  use  of<br /></span><span style="font-size:85%;">               the  number range with use of the -f option.  With<br /></span><span style="font-size:85%;">               -f, some device renumberings may not  take  effect<br /></span><span style="font-size:85%;">               until  a  reboot or a re-import (just as with open<br /></span><span style="font-size:85%;">               volumes).  Also, if you force volumes in two  disk<br /></span><span style="font-size:85%;">               groups  to use the same device number, then one of<br /></span><span style="font-size:85%;">               the volumes is temporarily renumbered on the  next<br /></span><span style="font-size:85%;">               reboot.   Which volume device is renumbered should<br /></span><span style="font-size:85%;">               be considered random, except that  device  number-<br /></span><span style="font-size:85%;">               ings in the rootdg disk group take precedence over<br /></span><span style="font-size:85%;">               all others.<br /></span><span style="font-size:85%;">               The -f option should be used  only  when  swapping<br /></span><span style="font-size:85%;">               the  device number ranges used by two or more disk<br /></span><span style="font-size:85%;">               groups.  To swap the number ranges  for  two  disk<br /></span><span style="font-size:85%;">               groups,  you  would  use  -f  when renumbering the<br /></span><span style="font-size:85%;">               first disk group to use the range  of  the  second<br /></span><span style="font-size:85%;">               disk  group.  Renumbering the second disk group to<br /></span><span style="font-size:85%;">               the first range does not require the use of -f.<br /></span><span style="font-size:85%;"><br /></span>
  • Sun Cluster does not work with Veritas DMP. DMP can be disabled before installing the software by putting in dummy symlinks, etc.
  • scvxinstall — is a shell script that automates VxVM installation in a Sun Clustered env.
  • scvxinstall automates the following things:
    • tries to disable DMP (vxdmp)
    • installs correct cluster package
    • automatically negotiates a vxio major number and properly edits /etc/name_to_major
    • automates rootdg initialization process and encapsulates boot disk
      • –> gives different device names for the /global/.devices/node@# volumes on each side –> edites teh vfstab properly for this same volume. The problem is this particular line as DID device on it, and VxVM doesn’t understand DID devices. –> installs a script to “reminor” the rootdg on the reboot –> reboots the node so that VxVM operates properly.

 Posted by at 8:46 pm

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