Hi. I have three servers with 7 hard drives (without HW RAID controller) that I wish to use to create a Gluster cluster. I am looking a way to have 2 replicas with 3 nodes, because I need much storage space and 2 nodes are not enough, but I wish to have the same security I'd have using a RAID5 on a node. So I wish my data to be protected if one (or two) of 7 hard drives will fail on the same node and if an entire node of three will fail. Is it possibile? Could you help me to find out the correct way? Thank you very much! Bye. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://supercolony.gluster.org/pipermail/gluster-users/attachments/20140101/a49b0dcd/attachment.html>
Since you don't have HW RAID, it might be wise to use software RAID (md-RAID or LVM) to aggregate drives and then allocate two bricks per server. This gives you a nice even number of bricks for use with your distributed-replica-2 setup. Note that if you were to lose one node, you will lose two bricks in this setup! It would be wise to allocate your storage in such a way that minimizes the impact of losing an entire RAID volume. You'll have to weigh the risks against your need for storage space. Also, run a few failure simulations so that if you do lose a node or brick down the way, you will know what to do. If your bricks are on the same RAID volume(s) as your OS, you'll also have to be able to replace the OS and configuration quickly (from backup or using automatic install and configuration) in order to recover from a major failure. Some people run their OSes on a separate RAID-1 configuration (sometimes even off of USB drives!) in order to isolate brick failure from the OSes. My opinion: 7 drives isn't very many for a storage node and it will be difficult to obtain an optimal configuration with two bricks per server. You would be wise to purchase another server or additional storage chassis for your existing servers in order to obtain a more optimal configuration. On Wed, Jan 1, 2014 at 1:06 PM, shacky <shacky83 at gmail.com> wrote:> Hi. > > I have three servers with 7 hard drives (without HW RAID controller) that > I wish to use to create a Gluster cluster. > > I am looking a way to have 2 replicas with 3 nodes, because I need much > storage space and 2 nodes are not enough, but I wish to have the same > security I'd have using a RAID5 on a node. > > So I wish my data to be protected if one (or two) of 7 hard drives will > fail on the same node and if an entire node of three will fail. > > Is it possibile? > Could you help me to find out the correct way? > > Thank you very much! > Bye. > > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://supercolony.gluster.org/mailman/listinfo/gluster-users >-- Justin Dossey CTO, PodOmatic -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://supercolony.gluster.org/pipermail/gluster-users/attachments/20140102/ee883214/attachment.html>
It's logical impossible what you ask for! on a raid5, if two (you said two) fails ALL data IS lost. think harder! As Justin supossed, go for securing your bricks with (soft)raid (or maybe raidz) and extend the space by striping it onto several server. In a disaster, a hard disk, and 10hours later a second one, fails, while you are sick and out of office, and your apprentice has to handle it. out the bad HD, in the good one. cross fingers (that is, that the new HDs are good) and rock on. Simple solutions for complex problems! I don't argue that it is not totally impossible to build, with gluster, what you are asking for, but to my taste it wouldn't b "nice nd easy" (i.e. rocksolid) Bernhard On 01.01.2014, at 22:06, shacky <shacky83 at gmail.com> wrote:> Hi. > > I have three servers with 7 hard drives (without HW RAID controller) that I wish to use to create a Gluster cluster. > > I am looking a way to have 2 replicas with 3 nodes, because I need much storage space and 2 nodes are not enough, but I wish to have the same security I'd have using a RAID5 on a node. > > So I wish my data to be protected if one (or two) of 7 hard drives will fail on the same node and if an entire node of three will fail. > > Is it possibile? > Could you help me to find out the correct way? > > Thank you very much! > Bye. > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://supercolony.gluster.org/mailman/listinfo/gluster-users