AJ Lewis wrote: > On Wed, Jul 27, 2005 at 09:06:01AM -0400, Matthew Gillen wrote: > >>Fury wrote: >> >>>I've racked my brain on this one, so hopefully someone will be of some help. >>> >>>I'm trying to set up two servers which share a drive and do not have a >>>Single Point of Failure. They are on a local network with each other. >>> The best solution would be to have /dev/sda1 on one server mirrored >>>with /dev/sda1 on the second server. >>>... >>>A second solution was to use GFS/GNBD. I can export each drive to the >>>other server, and do RAID 1 (on both servers) between the local >>>/dev/sda1 and the remote gnbd device. I then format the raid device >>>with GFS so both servers can mount it. >>> >>>Surprisingly, this last system works. Both systems can mount the >>>drive and read-write to it. However, if either server in this >>>configuration drops dead, the other server cannot deal with the dead >>>gnbd device, and the raid device and mount point are no longer usable. >>> I'm sure there are numerous other problems with this setup, also. >>> >>>So I'm looking for ideas. With two servers, how can I mirror a drive >>>in real-time, and allow for failover? >> >>You might want to use something more like iSCSI + RAID: >>http://linux-iscsi.sourceforge.net/ > > > How is that different than GNBD + RAID? The issue isn't the network > transport, it's recovery of a RAID on two nodes simultaneously. I don't think he was even worried about recovery, although you're right and that's another problem. I read that he couldn't access anything after a failure of one server, which is what I was addressing. Honestly, I don't know how GNBD works. But if it makes makes the remote volume look local and doesn't report problems in a way that RAID understands (or at all), I can see how things would hang (just like a client system would hang if an NFS server for a mounted filesystem went down). I imagine (but I don't know from personal experience) that iSCSI (with the ConnFailTimeout=x sec) would report a failed write and RAID knows how to handle that. But, like I said, I don't know for sure about any of this, since I haven't tried it. However, the page: http://linas.org/linux/raid.html mentions iSCSI, so it appears that some people have gotten it to work. --Matt _______________________________________________ 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/
