At Network Presence we don’t meter or charge for data exchanged between customer VPS, so you can purchase 2 x VPS from us and use open-source Disk Clustering technologies described below to share a common filesystem between your VPS.<\/p>\n
Here’s the steps (down to the commands to run as root) to install and configure the DRBD Network Disk on Debian 7 running across a 2 Node Cluster:<\/p>\n
Some Linux or system level requirements or pre-install setup tasks are:<\/p>\n
1) Ensure the \/etc\/hosts files are the same on each Node and that it contains entries for each DB Node’s IP addresses and hostname (both the node hostname and its fully qualified hostname).<\/p>\n
eg: 2) Ensure that each Node’s Firewall permits each other node host IP addresses access to ports 7788 to 7799.<\/p>\n 3) The example setup below assumes that you have a Disk Device of the same size on both nodes, in this example that device is refered to as “\/dev\/xvdaX” but it could be a “\/dev\/loop0” device created on each node with commands like:<\/p>\n And use “\/dev\/loop0” in the DRBD config below, not “\/dev\/xvdaX” (for example).<\/p>\n Then, run\/do the following on each Node to get the DRBD Disk live, sync’ing and running on the first node ASAP:<\/p>\n a) Install per-requisite Debian Packages:<\/p>\n b) Configure a DRBD Disk in your VPS:<\/p>\n startup { on node1 { c) Initialize the device for DRBD use:<\/p>\n d) Sync the DRBD Disk across your VPS Nodes:<\/p>\n On one of the node’s (eg: Node 1), run:<\/p>\n Speed the sync’s up with a command like (only needed on one node) :<\/p>\n If you want this faster sync rate by default, then add the following to your DRBD config file (listed above) before the ‘resource’ line :<\/p>\n e) Activate the disk as Primary\/Primary:<\/p>\n Easiest way after the disk sync (above) has finished: Reboot Node 2.<\/p>\n Or, you can enter the command on Node 2 of:<\/p>\n (where DISK1 is the resource name listed in the DRBD config file above)<\/p>\n f) Once Node 2 restarts the DRBD Cluster should sync primary:primary on the 2 Nodes.<\/p>\n g) From here, you can create a Distributed or Clustered Filesystem on \/dev\/drbd1 and mount it on the two nodes. eg: Use XFS or OCFS2 or GlusterFS or another distributed or clustered filesystem type.<\/p>\n A Filesystem which specifically supported multiple host mounting or is a Clustered Filesystem is required to be able to share and have the filesystem mounted on each host. ie: EXT3 or EXT4 is not capable of this and can only be mounted on one host at a time (even though the underlying disk device is common (\/dev\/drbd1) between the nodes).<\/p>\n Further posts here will build on this post to describe creating and using OCFS2 as a Clustered Filesystem across the two DRBD Nodes.<\/p>\n FYI and regards, At Network Presence we don’t meter or charge for data exchanged between customer VPS, so you can purchase 2 x VPS from us and use open-source Disk Clustering technologies described below to share a common filesystem between your VPS. Here’s … Continue reading
\n192.168.0.1 node1 node1.domain.name
\n192.168.0.2 node2 node2.domain.name<\/code><\/p>\ndd if=\/dev\/zero of=\/storage\/somewhere\/drbd.disk bs=1024k count=1024
\nlosetup \/dev\/loop0 \/storage\/somewhere\/drbd.disk<\/code><\/p>\napt-get -y install drbd8-utils<\/code><\/p>\ncat << EOF > \/etc\/drbd.d\/DISK1.res
\nresource DISK1 {<\/p>\n
\n become-primary-on both;
\n }
\n net {
\n ## not recommended to enable the allow-two-primaries option upon initial configuration. You should do so after the initial resource synchronization has completed.
\n allow-two-primaries; ## After you enable the allow-two-primaries option for this resource, you will be able to promote the resource to the primary role on both nodes.
\n after-sb-0pri discard-zero-changes;
\n after-sb-1pri discard-secondary;
\n after-sb-2pri disconnect;
\n }<\/p>\n
\n device \/dev\/drbd1;
\n disk \/dev\/xvdX;
\n address 192.168.0.1:7789;
\n meta-disk internal;
\n }
\n on node2 {
\n device \/dev\/drbd1;
\n disk \/dev\/xvdX;
\n address 192.168.0.2:7789;
\n meta-disk internal;
\n }
\n}
\nEOF
\n<\/code><\/p>\ndrbdadm create-md DISK1<\/code><\/p>\ndrbdadm up all
\ndrbdadm -- --overwrite-data-of-peer primary all<\/code><\/p>\ndrbdsetup \/dev\/drbdX syncer -r 110M<\/code><\/p>\ncommon { syncer { rate 100M; } }<\/code><\/p>\ndrbdadm primary DISK1<\/code><\/p>\nroot@node2:~# cat \/proc\/drbd
\nversion: 8.3.[..]
\n 1: cs:Connected ro:Primary\/Primary ds:UpToDate\/UpToDate C r-----<\/code><\/p>\n
\nRichard.<\/p>\n","protected":false},"excerpt":{"rendered":"