iSCSI Management

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Nexfs includes a full feature integrated iSCSI server (target) with direct access to the storage pool which can offer higher performance than using an external iSCSI server.

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iSCSI Service Management

 

Enabling the Integrated iSCSI server

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The integrated Nexfs iSCSI server must first be enabled by setting ISCSIENABLED to 1 (enabled), to disable the iSCSI server set ISCSIENABLED to 0

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Example of using nexfscli to enable the iSCSI service on Nexfs start:

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# nexfscli configfile set ISCSIENABLED 1
Updated Configuration file

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If Nexfs is already running, you can enable iSCSI without requiring a restart with:

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# nexfscli liveconfig set ISCSIENABLED 1

Updated Live Configuration

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By default Nexfs will manage up to 16 iSCSI LUNs, this is a soft limit that can be increased through the ISCSIMAXLUNS setting to a maximum of 256 LUNs

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More information on managing Nexfs using nexfscli can be found here

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Configuring iSCSI

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The integrated iSCSI service is managed through a standard JSON formatted configuration file, the easiest way to view and modify the iSCSI server is by using the nexfscli management command.

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Viewing iSCSI configuration​ with nexfscli

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You can view or make a copy of the current loaded iSCSI LUN configuration using nexfscli, to view the export configuration run:

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# nexfscli iscsi getconf

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To save a copy of the LUNs configuration to a file, include a filename at the end of the getconf command, for example, to save a copy to a file in /tmp called nexfsiscsiluns, run:

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# nexfscli iscsi getconf /tmp/nexfsiscsiluns

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Viewing the active iSCSI system with nexfscli

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For a list of all active Targets and LUNs run:

# nexfscli iscsi show targets

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For a list of all active LUNs attached to Target 1 (Change 1 in the command to the Target ID you want a list of LUNs for) run:

# nexfscli iscsi show target 1

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To list Nexfs iSCSI Configured Interfaces

# nexfscli iscsi show interfaces

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To list Nexfs iSCSI Configured Users

# nexfscli iscsi show accounts

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To list all active connections 

# nexfscli iscsi show sessions

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To list all active connections attached to target id 1

# nexfscli iscsi show targetsessions 1

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Using tgtadm with Nexfs

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Nexfs allows its live configuration and stats to be viewed with tgtadm, tgtadm is part of the tgt package not installed by default with nexfs and must be installed manually.

 

Note: it is not possible to make Nexfs iSCSI configurable changes with tgtadm.

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View the Nexfs iSCSI system with tgtadm

 

For a list of configured Nexfs iSCSI LUNs using tgtadm run:

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# tgtadm --lld iscsi --op show --mode target

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Note: Nexfs and tgt use different terms, for example when viewing configuration, portals are called interfaces in Nexfs, and tgt ACLs are called "CHAP Authentication Accounts". You continue to use the tgt term when requesting a configuration type from Nexfs using tgtadm, Nexfs knows how to correctly map the tgt term to the Nexfs term.  

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To list Nexfs iSCSI Configured Interfaces

# tgtadm --lld iscsi --op show --mode portal

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To list Nexfs iSCSI Configured Users

# tgtadm --lld iscsi --op show --mode account

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To list all active connections attached to target id 1

# tgtadm --lld iscsi --op show --mode conn --tid 1

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Updating, creating and removing iSCSI Configurations 

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You can add, remove and update existing iSCSI LUNs using nexfscli, first create a correctly formatted JSON file that contains the configuration changes

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# nexfscli iscsi putconf /tmp/nexfsiscsiluns

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Where /tmp/nexfsiscsiluns is the location of the JSON file which contains the new configuration.

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Once loaded check that the configuration has been accepted by viewing the active iSCSI Luns as detailed above, check the nexfs logfile (defaults to syslog) for details if any formatting errors were encountered loading the new configuration file.

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Configuration changes are persisted between Nexfs restarts, there is no requirement to reload the iSCSI JSON configuration each time Nexfs is started.