[Linux-cluster] clvmd problems with centos 6.3 or normal clvmd behaviour?

Thu Aug 2 14:12:24 UTC 2012

can you show me your lvm.conf?

2012/8/2 Gianluca Cecchi <gianluca.cecchi at gmail.com>

> On Thu, 2 Aug 2012 07:07:25 -0600 Corey Kovacs wrte:
> > I might be reading this wrong but just in case, I thought I'd point this
> out.
> >
> [snip]
> > A single node can maintain quorum since 2+3>(9/2).
> > In a split brain condition where a single node cannot talk to the other
> nodes, this could be disastrous.
>
> Thanks for your input, Corey.
> As I said before, at this moment I'll have only one node on a site so
> I'm also tweaking config to be able to work with one node alone
>
> Anyway I refer to this sentence in manual, also for more than two
> nodes configuration (example pertains to a 13 nodes cluster):
>
> "
> A cluster must maintain quorum to prevent split-brain issues. If
> quorum was not enforced, quorum, a communication error on that same
> thirteen-node cluster may cause a situation where six nodes are
> operating on the shared storage, while another six nodes are also
> operating on it, independently. Because of the communication error,
> the two partial-clusters would overwrite areas of the disk and corrupt
> the file system. With quorum rules enforced, only one of the partial
> clusters can use the shared storage, thus protecting data integrity.
> Quorum doesn't prevent split-brain situations, but it does decide who
> is dominant and allowed to function in the cluster. Should split-brain
> occur, quorum prevents more than one cluster group from doing
> anything.
> "
>
> This said, in my case my problem is not with quorum, that is gained
> when quorum disk becomes master, but with clvmd freezing without
> showing any error
> As suggested I set up logging for both cluster and lvm.
>
> I also configured lvmetad
>
> The diff between previous lvm.conf and current for further tests is this:
> # diff -u lvm.conf lvm.conf.pre020812
> --- lvm.conf    2012-08-02 14:48:31.172565731 +0200
> +++ lvm.conf.pre020812  2012-08-02 01:33:55.878511113 +0200
> @@ -232,8 +232,7 @@
>
>      # Controls the messages sent to stdout or stderr.
>      # There are three levels of verbosity, 3 being the most verbose.
> -    #verbose = 0
> -    verbose = 2
> +    verbose = 0
>
>      # Should we send log messages through syslog?
>      # 1 is yes; 0 is no.
> @@ -242,7 +241,6 @@
>      # Should we log error and debug messages to a file?
>      # By default there is no log file.
>      #file = "/var/log/lvm2.log"
> -    file = "/var/log/lvm2.log"
>
>      # Should we overwrite the log file each time the program is run?
>      # By default we append.
> @@ -251,8 +249,7 @@
>      # What level of log messages should we send to the log file and/or
> syslog?
>      # There are 6 syslog-like log levels currently in use - 2 to 7
> inclusive.
>      # 7 is the most verbose (LOG_DEBUG).
> -    #level = 0
> -    level = 4
> +    level = 0
>
>      # Format of output messages
>      # Whether or not (1 or 0) to indent messages according to their
> severity
> @@ -422,8 +419,7 @@
>      # Check whether CRC is matching when parsed VG is used multiple times.
>      # This is useful to catch unexpected internal cached volume group
>      # structure modification. Please only enable for debugging.
> -    #detect_internal_vg_cache_corruption = 0
> -    detect_internal_vg_cache_corruption = 1
> +    detect_internal_vg_cache_corruption = 0
>
>      # If set to 1, no operations that change on-disk metadata will be
> permitted.
>      # Additionally, read-only commands that encounter metadata in
> need of repair
> @@ -483,8 +479,7 @@
>      # libdevmapper.  Useful for debugging problems with activation.
>      # Some of the checks may be expensive, so it's best to use this
>      # only when there seems to be a problem.
> -    #checks = 0
> -    checks = 1
> +    checks = 0
>
>      # Set to 0 to disable udev synchronisation (if compiled into the
> binaries).
>      # Processes will not wait for notification from udev.
>
> cluster.conf changes
> # diff cluster.conf cluster.conf.51
> 2,6c2
> < <cluster config_version="52" name="clrhev">
> <       <dlm log_debug="1" plock_debug="1"/>
> <       <logging>
> <               <logging_daemon name="qdiskd" debug="on"/>
> <       </logging>
> ---
> > <cluster config_version="51" name="clrhev">
>
> In attach I send two files:
> lvm2.log with mark separating before and after issue of clvmd start command
> clvmd start output.txt that is the output during "service clvmd start"
> command
>
> to be able to do so, I started in signle user mode and then started
> the services one at a time as in
>
> /etc/rc.d/rc3.d/S*
>
> but anticipating the ssh daemon, so that I'm able to login remotely
> In fact after clvmd freezes I can only run a pair of sync commands and
> power off....
>
> If I'm not missing something stupid I can also post a bugzilla vs
> Centos Bug tracker and then eventually someone will report upstream if
> reproducible
>
> Gianluca
>
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