On 05/04/2016 11:12 AM, Jes Sorensen wrote:
Guoqing Jiang [off-list ref] writes:
quoted
For cluster raid, we do need at least two nodes for it,
the two patches add the checks before create and change
bitmap.
Thanks,
Guoqing
Guoqing Jiang (2):
Create: check the node nums when create clustered raid
super1: don't update node nums if it is not more than 1
Create.c | 7 ++++++-
super1.c | 5 +++++
2 files changed, 11 insertions(+), 1 deletion(-)
Hi Guoqing,
I am a little confused on this one - albeit I haven't looked at it in
detail. Why should it not be possible to start a cluster with one node?
In theory you should be able to do that, and then add nodes later?
Not typically. A single node of a cluster is likely the odd man out, so
starting it and allowing changes to the underlying device has a high
potential of creating split brain issues. For that reason, most cluster
setups require some minimum (usually 2) for a quorum before they will
start. Otherwise, given a three node cluster, you could end up with
three separate live filesystems and the need to merge changes between
them to bring the cluster back into sync.
--
Doug Ledford [off-list ref]
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