On Wed, Nov 05, 2008 at 05:06:05PM -0500, Scot Kreienkamp wrote: > Hi Everyone… > > > > I have a difficult LVM question that I’m wrestling with. Hopefully someone can > help. > > > > I have two hosts with 50 gigs of local RAID5 storage. (I am using only local > storage due to performance problems with our SAN, so shared storage is out of > the picture.) I have that divided into three LVM partitions on each host, 5 > gigs for /, 5 gigs for swap, and 40 gigs mounted on /var/lib/pgsql. I need to > do a real-time mirror of /var/lib/pgsql (LogVol02) to the second host. I was > trying to use LVM to do that via Network Block Device. So on host2 I exported > LogVol02 via NBD, and imported it into host1. I then added that to VolGroup00 > and used lvconvert to establish the mirror. That all worked great. The > problem is that I don’t know how to reverse that process then and mount > LogVol02 in host2 without destroying the partition, with or without NBD; the > second host doesn’t have any information on the LVM partition so it wouldn’t > know how to do anything with it. That’s where I’m stuck. > > > > Basically what I’m after is I need to do a real-time mirror of the postgres > database volume to a second host for recovery in case of an emergency. If > there’s a way I can use LVM to do this, or if someone can suggest a better way, > I’m all ears. You heard of DRBD? http://www.drbd.org A year from now (or some such) we may have some successor of DRBD, better integrated with device-mapper and LVM, and with some additional features -- at least that is the plan. But right now, I think that just going with DRBD is your best bet for this exact purpose. (though obviously I'm biased.) -- : Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
