View source for ISCSI Raid and Clustered File Systems

{{Obsolete|SCST is deprecated since Alpine 2.6 in favor of [[Linux_iSCSI_Target_(TCM)|TCM]] and OCFS2 isn't available in Alpine 3.6}} 

This document describes how to created a raided file system that is exported to multiple host via ISCSI.

== Raid Configuration ==

Very Similar to [[Setting up a software RAID array]].

 apk install mdadm

 mdadm --create --level=5 --raid-devices=3 /dev/md0 /dev/hda /dev/hdb /dev/hdc

To see the status of the creation of these devices

 cat /proc/mdstat

You Don't have to wait to continue to use the disk.

== iSCSI Target Config ==

[http://scst.sourceforge.net/target_iscsi.html SCST] is recommended over [http://iscsitarget.sourceforge.net/ IET], due to bugfixes, performance and RFC compliance. 
For a detailed config how-to please look at [[High_performance_SCST_iSCSI_Target_on_Linux_software_Raid]]

== Initiator Config ==

 iscsiadm --mode node --targetname NAME_OF_TARGET --portal IP_OF_TARGET --login

This should then give you a device /dev/sda. Check by dmesg.

 fdisk /dev/sda

Create a partition to use. sda1 file system type 83

Add ocfs2 tools (available in Alpine 2.3 or greater)

 apk add ocfs2-tools

It can take care of starting and stopping services, copying the cluster.conf between nodes,creating the filesystem, and mounting it. 

Need to create a /etc/ocfs2/cluster.conf. 

This configuration file should be the same on all the nodes in the cluster. Should look similar to the following...

node:
        ip_port = 7777
        ip_address = 192.168.1.202
        number = 0
        name = bubba
        cluster = ocfs2

node:
        ip_port = 7777
        ip_address = 192.168.1.102
        number = 1
        name = bobo
        cluster = ocfs2

cluster:
        node_count = 2
        name = ocfs2

Load modules:

 echo ocfs2 >> /etc/modules
 echo dlm >> /etc/modules

 modprobe ocfs2
 modprobe dlm

Mount ocfs2 metafilesystems

 echo none /sys/kernel/config configfs defaults 0 0 >> /etc/fstab
 echo none /sys/kernel/dlm ocfs2_dlmfs defaults 0 0 >> /etc/fstab

Start ocfs2 cluster

 /etc/init.d/o2cb start

Run the following command only on one node. 

 mkfs.ocfs2 -L LABELNAME /dev/sda1

Run the following command on both nodes.

 /etc/init.d/o2cb enable

 mount /dev/sda1 /media/iscsi1

Now you can create read/write/change on both machines to the one drive at the same time.

[[Category:Storage]]