[Linux-cluster] Cluster with shared storage on low budget
yvette at dbtgroup.com
Tue Feb 15 18:19:53 UTC 2011
Thomas Sjolshagen wrote:
> Just so you realize; If you intend to use clvm (i.e. lvme in a cluster
> where you expect to be able to write to the volume from more than one
> node at/around the same time w/o a full-on failover), you will _not_
> have snapshot support. And no, this isn't "not supported" as in "nobody
> to call if you encounter a problem", it's "not supported" as in "the
> tools will not let you create a snapshot of the LV".
i've been listening to this discussion with much interest, as we would
like to improve the currency of our backup files.
right now we have an ensemble of GFS2 LV's ("pri") as our primary data
store, and a "matching ensemble" of XFS LV's ("bak") as our backup data
store. an hourly cron job rsync's all LV's in the ensemble from pri =>
bak. it's incredibly reliable, but this reduces our mean backup
currency by 1/2 hour. one upside is that i've got snapshots that are
only 1/2 hour old, and are daily backed up to tape.
the conversation seems to indicate that we can change the bak LV's from
XFS to GFS2 and have drbd auto-sync the pri LV changes made to the bak
LV's - yes? this would reduce our backup currency from a mean of 1/2
hour to theoretically, "atomic" (more likely "mere seconds"). i assUme
we have to change from XFS to GFS2, as drbd doesn't appear to do file
if our assumptions are correct, are there any guides / manuals / doc on
how to do this? it's most tempting to try, since if it doesn't work,
the hourly cron rsync's could be simply reinstated.
many thanks in advance to any and all who can advise...
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