125 lines
3.7 KiB
Markdown
125 lines
3.7 KiB
Markdown
---
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date: 2012-03-20
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title: Add SAN functions to Highly Available NFS/NAS
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category: linux
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---
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This based on my last post where I documented building a Highly
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Available NFS/NAS server.
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There is not a huge amount that needs to be done in order to add iSCSI
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functionality as well.
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Add a file called */etc/drbd/iscsi.res* containing:
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resource iscsi {
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on nfs1 {
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device /dev/drbd1;
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disk /dev/vdc;
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meta-disk internal;
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address 10.0.0.1:7789;
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}
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on nfs2 {
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device /dev/drbd1;
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disk /dev/vdc;
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meta-disk internal;
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address 10.0.0.2:7789;
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}
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}
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This differs from the previous resource in 2 ways. Obviously it using a
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different physical disk. Also the port number of the address is
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incremented; each resource has to have its own port to communicate on.
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# Configure Heartbeat
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Add a new resource to */etc/ha.d/haresources*:
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iscsi1.snellwilcox.local IPaddr::10.0.0.101/24/eth0 drbddisk::iscsi tgtd
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Same primary host, new IP address, new drbd resource and of course the
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service to be controlled (tgtd in this case).
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I also made a couple of changes to */etc/ha.d/ha.cf*:
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keepalive 500ms
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deadtime 5
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warntime 10
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initdead 120
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This changes the regularity of the heartbeat packets from every 2
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seconds to 2 every second. We also say that a node is dead after only 5
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seconds rather than after 30.
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# Configure an iSCSI Target
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Tgtd has a config file that you can use in */etc/tgt/targets.conf*. It
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is an XML file, so add entry like:
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<target iqn.2011-07.world.server:target0>
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# provided devicce as a iSCSI target
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backing-store /dev/vg_matthew/lv_iscsi1
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# iSCSI Initiator's IP address you allow to connect
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initiator-address 192.168.1.20
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# authentication info ( set anyone you like for "username", "password" )
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</target>
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The target name is by convention
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*iqn.year-month.reverse-domainname:hostname.targetname*. Each backing
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store will be a seperate LUN. A discussion of this is out of the scope
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of this article.
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By default, this config file is disabled. Enable it by un-commenting the
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line `#TGTD_CONFIG=/etc/tgt/targets.conf` in */etc/sysconfig/tgtd*. You
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can now enable the target with service tgtd reload.
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Now when you run `tgtadm –mode target –op show` you should get something
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like:
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Target 1: iqn.2012-03.com.example:iscsi.target1
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System information:
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Driver: iscsi
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State: ready
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I_T nexus information:
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LUN information:
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LUN: 0
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Type: controller
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SCSI ID: IET 00010000
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SCSI SN: beaf10
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Size: 0 MB, Block size: 1
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Online: Yes
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Removable media: No
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Readonly: No
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Backing store type: null
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Backing store path: None
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Backing store flags:
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LUN: 1
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Type: disk
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SCSI ID: IET 00010001
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SCSI SN: beaf11
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Size: 8590 MB, Block size: 512
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Online: Yes
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Removable media: No
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Readonly: No
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Backing store type: rdwr
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Backing store path: /dev/drbd/by-res/iscsi
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Backing store flags:
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Account information:
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ACL information:
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ALL
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# Connect An Initiator
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Install the iscsi utils:
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yum install iscsi-initiator-utils
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chkconfig iscsi on
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chkconfig iscsid on
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Discover the targets on the host and login to the target.
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iscsiadm -m discovery -t sendtargets -p 10.0.0.101
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iscsiadm -m node --login
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If you run `cat /proc/partitions` you will see an new partition has
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appeared. You can do whatever you want with it.
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