Re: [linux-lvm] the lvm shared storage question of the week

[Jean Spirat <jeanspirat@squirk.org>]

> CLVM needs a distributed lock manager to work (which communicates over
> the network, not via the disk).  This is usually provided with the help
> of the RedHat Cluster Suite.
>   

locking on the disk seems easier to setup than network port firewall 
rules and so on but if it was not done i assume there was a good reason 
for it that my poor brain cannot see :)  if each node is gived a unique 
key then you could use on disk  locking with a special lock metadata and 
a timestamps for reloading configuration for the other node. Of course 
it seems too easy to have not been thinked about so there must be a 
major flaw in my thinking :)



> by default, locking type 2 or 3 requires clvmd, which as I say will
> require a cluster setup of some kind.
>
> You *can* work without a cluster manager but I'm not sure how advised it
> is.  So you leave your locking type as 1 and use "lvchange
> --refresh /dev/vg/*" on all nodes to reload metadata from disk whenever
> you make a change.  Can be a bit risky.
>
> John.
>   
strange that this use case has not handled in an safer/easier way :)


if each lvm partition is mounted on only one box where does the risk 
lies in your opinion ?

regards,
Jean.