================================================================= Linux* Open-iSCSI ================================================================= February 28, 2005 Contents ======== - 1. In This Release - 2. Introduction - 3. Installation - 4. Open-iSCSI daemon - 5. Open-iSCSI Configuration Utility - 6. Configuration - 7. Getting Started - 8. TBD - Appendix A. SendTargets snapshot. 1. In This Release ================== This file describes the Linux* Open-iSCSI Initiator. The software was tested on AMD Opteron (TM) and Intel Xeon (TM). The latest development release is available at: http://www.open-iscsi.org For questions, comments, contributions send e-mail to: open-iscsi@googlegroups.com 1.1. Features - highly optimized and very small-footprint data path; - multiple outstanding R2Ts; - persistent configuration database; - SendTargets discovery; - CHAP; - PDU header Digest; - multiple sessions; - multi-connection sessions. For the most recent list of features please refer to: http://www.open-iscsi.org/cgi-bin/wiki.pl/Roadmap 2. Introduction =============== Open-iSCSI project is a high-performance, transport independent, multi-platform implementation of RFC3720 iSCSI. Open-iSCSI is partitioned into user and kernel parts. The kernel portion of Open-iSCSI is a from-scratch code licensed under GPL. The kernel part implements iSCSI data path (that is, iSCSI Read and iSCSI Write), and consists of two loadable modules: iscsi_if.ko and iscsi_tcp.ko. User space contains the entire control plane: configuration manager, iSCSI Discovery, Login and Logout processing, connection-level error processing, Nop-In and Nop-Out handling, and (in the future:) Text processing, iSNS, SLP, Radius, etc. The user space Open-iSCSI consists of a daemon process called iscsid, and a management utility iscsiadm. 3. Installation =============== As of today, the Open-iSCSI Initiator requires a host running the Linux operating system with kernel version 2.6.11, or later. You need to enable "Cryptographic API" under "Cryptographic options" in the kernel config. You also need to enable "CRC32c CRC algorithm" if you use header or data digests. They are the kernel options, CONFIG_CRYPTO and CONFIG_CRYPTO_CRC32C, respectively. Compilation of the kernel Opne-iSCSI modules requires a path to kernel sources: make KSRC= or cross-compilation: make KSRC= KARCH="ARCH=um" 4. Open-iSCSI daemon ==================== The daemon implements control path of iSCSI protocol, plus some management facilities. For example, the daemon could be configured to automatically re-start discovery at startup, based on the contents of persistent iSCSI database (see next section). For help, run: ./iscsid --help Usage: iscsid [OPTION] -c, --config=[path] Execute in the config file (/etc/iscsid.conf). -f, --foreground run iscsid in the foreground -d, --debug debuglevel print debugging information -u, --uid=uid run as uid, default is current user -g, --gid=gid run as gid, default is current user group -h, --help display this help and exit -v, --version display version and exit 5. Open-iSCSI Configuration Utility =================================== Open-iSCSI persistent configuration is implemented as a DBM database available on all Linux installations. The database contains two tables: - Discovery table (discovery.db); - Node table (node.db). The regular place for iSCSI database files: /var/db/iscsi/*.db The iscsiadm utility is a command-line tool to manage (update, delete, insert, query) the persistent database. The utility presents set of operations that a user can perform on iSCSI nodes, sessions, connections, and discovery records. Note that some of the iSCSI Node and iSCSI Discovery operations do not require iSCSI daemon (iscsid) loaded. For help, run: ./iscsiadm --help Usage: iscsiadm [OPTION] -m, --mode specify operational mode op = -m discovery --type=[type] --portal=[ip:port] --login perform [type] discovery for target portal with ip-address [ip] and port [port]. Initiate Login for each discovered target if --login is specified -m discovery display all discovery records from internal persistent discovery database -m discovery --record=[id] --login perform discovery based on record [id] in database -m discovery --record=[id] --op=[op] [--name=[name] --value=[value]] perform specific DB operation [op] for specific discovery record with [id]. It could be one of: [new], [delete], [update] or [show]. In case of [update], you have to provide [name] and [value] you wish to update -m node display all discovered nodes from internal persistent discovery database -m node --record=[id] [--login|--logout] -m node --record=[id] --op=[op] [--name=[name] --value=[value]] perform specific DB operation [op] for specific node with record [id]. It could be one of: [new], [delete], [update] or [show]. In case of [update], you have to provide [name] and [value] you wish to update -m session display all active sessions and connections -m session --record=[id[:cid]] [--logout] perform operation for specific session with record [id] or display statistics if no operation specified. Operation will affect one connection only if [:cid] is specified -d, --debug debuglevel print debugging information -V, --version display version and exit -h, --help display this help and exit Usage Examples: 1) SendTargets iSCSI Discovery: ./iscsiadm -m discovery --type sendtargets --portal 192.168.1.1:3260 2) iSCSI Login: ./iscsiadm -m node --record 0f23e4 --login 3) iSCSI Logout: ./iscsiadm -m node --record 0f23e4 --logout 4) Changing iSCSI parameter: ./iscsiadm -m node --record 0f23e4 --op update \ -n node.cnx[0].iscsi.MaxRecvDataSegmentLength -v 65536 5) Adding custom iSCSI Node: ./iscsiadm -m node --op new --portal 192.168.0.1:3260 new iSCSI node record added: [0a45f8] 6) Removing iSCSI Node: ./iscsiadm -m node --op delete --record 0a45f8 7) Display iSCSI Node configuration: ./iscsiadm -m node --record 0a45f8 or ./iscsiadm -m node --op show --record 0a45f8 6. Configuration ================ The default configuration file is /etc/iscsid.conf. This file contains only configuration that could be overwritten by iSCSI Discovery, or manualy updated via iscsiadm utility. Its OK if this file does not exist in which case compiled-in default configuration will take place for newer discovered Target nodes. See the man page and the example file for the current syntax. (no man page yet...) 7. Getting Started ================== Right now there is no installation script. Just load the module with command: insmod iscsi_if.ko insmod iscsi_tcp.ko after that start iSCSI daemon process: ./iscsid or alternatively, start it with debug enabled and with output redirected to the current console: ./iscsid -d8 -f & and use configuration utility to add/remove/update Discovery records, iSCSI Node records or monitor active iSCSI sessions: ./iscsiadm To login: ./iscsiadm -m node --record --login where is the record of a discovered or manually added iSCSI Target Node (for iscsiadm usage examples see previous sections). 8. TBD ====== To be completed: - Kernel tracing and Troubleshooting - Immediate and not-so-immediate plans - Useful scripts - White paper on Open-iSCSI design Appendix A. SendTargets iSCSI Discovery session snapshot. ========================================================= -bash-2.05b# ./iscsiadm -m discovery -tst -p 10.16.16.223:3260 [02f611] 10.16.16.223:3260,1 iqn.2002-07.com.ttechnologies.target.a [01acd1] 17.1.1.223:3260,1 iqn.2002-07.com.ttechnologies.target.a -bash-2.05b# -bash-2.05b# ./iscsiadm -m node [02f611] 10.16.16.223:3260,1 iqn.2002-07.com.ttechnologies.target.a [01acd1] 17.1.1.223:3260,1 iqn.2002-07.com.ttechnologies.target.a -bash-2.05b# -bash-2.05b# ./iscsiadm -m discovery -tst -p 10.16.16.227:3260 [02fb91] 10.16.16.227:3260,1 iqn.2001-04.com.example:storage.disk2.sys1.xyz -bash-2.05b# -bash-2.05b# ./iscsiadm -m node [02f611] 10.16.16.223:3260,1 iqn.2002-07.com.ttechnologies.target.a [02fb91] 10.16.16.227:3260,1 iqn.2001-04.com.example:storage.disk2.sys1.xyz [01acd1] 17.1.1.223:3260,1 iqn.2002-07.com.ttechnologies.target.a