Install iSCSI in CentOS 6.6

Install iSCSI in CentOS 6.6

I. Introduction to ISCSI

ISCSI, internet SCSI, also known as IP-SAN, is a standard developed by IETF to map SCSI data blocks into Ethernet packets. ISCSI is a TCP/IP-based protocol used to establish and manage the connection between IP storage devices, hosts and clients, and create a storage area network (SAN ). SAN makes it possible to apply the SCSI protocol to high-speed data transmission networks. Such transmission is performed between multiple data storage networks at the block-level. The SCSI structure is based on the C/S mode. The common application environment is that devices are close to each other and these devices are connected by the SCSI bus.

The main function of iSCSI is to encapsulate and reliably transmit large amounts of data between the host system (initiator) and the storage device (target) on the TCP/IP network.

Basically, the iSCSI protocol is a method to transmit SCSI data blocks with short latencies over an IP network.

The complete iSCSI system topology is as follows:

Compared with traditional SCSI technology, iSCSI technology has the following three revolutionary changes:

1. The original SCSI used only on the local machine is transmitted through the TCP/IP network, so that the connection distance can be extended in an unlimited region;
2.  
3. The number of connected servers is infinite (the upper limit of the original SCSI-3 is 15 );
4.  
5. Because it is a server architecture, online resizing and dynamic deployment can also be realized.

ISCSI protocol structure:

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2. Build an ip san-based ISCSI Storage System

1. Planning:
2.  
3. Environment: CentOS 6.6 32-bit
4.  
5. Server IP Address: 192.168.1.43
6.  
7. Client IP Address: 192.168.1.111
8.  
9. Shared Disk:/dev/sdb

1. Configure the server

1. [Root @ localhost ~] # Yum-y install scsi-target-utils # install the server software
2.  
3. [Root @ node1 iscsi] # rpm-ql scsi-target-utils
4. /Etc/rc. d/init. d/tgtd
5. /Etc/sysconfig/tgtd
6. /Etc/tgt/targets. conf # configuration file
7. /Usr/sbin/tgt-admin
8. /Usr/sbin/tgt-setup-lun
9. /Usr/sbin/tgtadm
10. /Usr/sbin/tgtd
11. /Usr/sbin/tgtimg
12. /Usr/share/doc/scsi-target-utils-1.0.24
13. /Usr/share/doc/scsi-target-utils-1.0.24/README
14. /Usr/share/doc/scsi-target-utils-1.0.24/README. iscsi
15. /Usr/share/doc/scsi-target-utils-1.0.24/README. iser
16. /Usr/share/doc/scsi-target-utils-1.0.24/README. lu_configuration
17. /Usr/share/doc/scsi-target-utils-1.0.24/README. mmc
18. /Usr/share/man/man5/targets.conf.5.gz
19. /Usr/share/man/man8/tgt-admin.8.gz
20. /Usr/share/man/man8/tgt-setup-lun.8.gz
21. /Usr/share/man/man8/tgtadm.8.gz
22.  
23. [Root @ localhost ~] # Lsmod | grep scsi
24. Mptscsih 31330 1 mptspi
25. Mptbase 86744 2 mptspi, mptscsih
26. Scsi_transport_spi 19726 1 mptspi # Advanced Driver

Iscsi can be configured using commands or configuration files. We first use the command line for Configuration:

1. [Root @ node1 iscsi] # service tgtd start
2. Starting SCSI target daemon: [OK]
3.  
4. [Root @ node1 iscsi] # ss-tlnp | grep 3260 # Listening on port 3260
5. LISTEN 0 128: 3260: * users :( ("tgtd", 1188), ("tgtd", 11885 ))
6. LISTEN 0 128 *: 3260 *: * users :( ("tgtd", 11882, 4), ("tgtd", 11885, 4 ))
7.  
8. [Root @ localhost ~] # Tgtadm-L iscsi-o new-m target-t 1-T iqn.2015-08.com. feiyu. testsan: 1 # create a target,-t specify TID,-T specify name

Iqn indicates "ISCSI Qualified Name", or iqn for short.

1. [Root @ localhost ~] # Tgtadm-L iscsi-o show-m target
2. Target 1: iqn.2015-08.com. feiyu. testsan: 1
3. System information:
4. Driver: iscsi
5. State: ready
6. I _T nexus information:
7. LUN information:
8. LUN: 0
9. Type: controller
10. Scsi id: IET 00010000
11. Scsi sn: beaf10
12. Size: 0 MB, Block size: 1
13. Online: Yes
14. Removable media: No
15. Prevent removal: No
16. Readonly: No
17. Backing store type: null
18. Backing store path: None
19. Backing store flags:
20. Account information:
21. ACL information:

Then, set the LUN (Logical Unit Number). On the server side, you only need to create partitions without formatting:

1. [Root @ localhost ~] # Tgtadm-L iscsi-o new-m logicalunit-t 1-l 1-B/dev/sdb5 # create a LUN,-m indicates the mode,-l: LUN, -B: Device
2.  
3. [Root @ localhost ~] # Tgtadm-L iscsi-o bind-m target-t 1-I 192.168.0.0/16
4.  
5. [Root @ node1 iscsi] # tgtadm-L iscsi-o show-m target
6. Target 1: iqn.2015-08.com. feiyu. testsan: 1
7. System information:
8. Driver: iscsi
9. State: ready
10. I _T nexus information:
11. LUN information:
12. LUN: 0
13. Type: controller
14. Scsi id: IET 00010000
15. Scsi sn: beaf10
16. Size: 0 MB, Block size: 1
17. Online: Yes
18. Removable media: No
19. Prevent removal: No
20. Readonly: No
21. Backing store type: null
22. Backing store path: None
23. Backing store flags:
24. LUN: 1
25. Type: disk
26. Scsi id: IET 00010001
27. Scsi sn: beaf11
28. Size: 2107 MB, Block size: 512
29. Online: Yes
30. Removable media: No
31. Prevent removal: No
32. Readonly: No
33. Backing store type: rdwr
34. Backing store path:/dev/sdb5
35. Backing store flags:
36. Account information:
37. ACL information:
38.  
39. [Root @ node1 iscsi] # tgtadm-L iscsi-o bind-m target-t 1-I 192.168.0.0/16 # Set the shared area
40. [Root @ node1 iscsi] # tgtadm-L iscsi-o show-m target
41. Target 1: iqn.2015-08.com. feiyu. testsan: 1
42. System information:
43. Driver: iscsi
44. State: ready
45. I _T nexus information:
46. LUN information:
47. LUN: 0
48. Type: controller
49. Scsi id: IET 00010000
50. Scsi sn: beaf10
51. Size: 0 MB, Block size: 1
52. Online: Yes
53. Removable media: No
54. Prevent removal: No
55. Readonly: No
56. Backing store type: null
57. Backing store path: None
58. Backing store flags:
59. LUN: 1
60. Type: disk
61. Scsi id: IET 00010001
62. Scsi sn: beaf11
63. Size: 2107 MB, Block size: 512
64. Online: Yes
65. Removable media: No
66. Prevent removal: No
67. Readonly: No
68. Backing store type: rdwr
69. Backing store path:/dev/sda5
70. Backing store flags:
71. Account information:
72. ACL information:
73. 192.168.0.0/16
74.  
75. [Root @ localhost ~] # Tgtadm-L iscsi-o new-m logicalunit-t 1-l 2-B/dev/sdb6 # bind the second LUN

2. Configure the client

1. [Root @ node1 ~] # Yum install-y iscsi-initiator-utils # install the client
2.  
3.  
4. [Root @ node1 iscsi] # echo "InitiatorName = 'iscsi-iname-p iqn.2013-05.com. feiyu '">/etc/iscsi/initiatorname. iscsi # generate iqn
5. [Root @ node1 iscsi] # echo "InitiatorAlias = initiator1">/etc/iscsi/initiatorname. iscsi # define an alias
6.  
7. [Root @ node1 iscsi] # ls
8. Initiatorname. iscsi iscsid. conf
9. [Root @ node1 iscsi] # cat initiatorname. iscsi # view the defined data
10. InitiatorName = iqn.2015-08.com. feiyu: 201734bd52221
11. InitiatorAlias = initiator1
12.  
13. [Root @ node1 ~] # Service iscsi start # start the service. You need to start two services.
14. [Root @ node1 ~] # Service iscsid start
15. [Root @ node1 ~] # Chkconfig iscsi on
16. [Root @ node1 ~] # Chkconfig iscsid on

If the following error occurs, the firewall on the server may be irrelevant!

1. [Root @ node1 ~] # Iscsiadm-m discovery-t st-p 192.168.1.43
2. Starting iscsid: [OK]
3. Iscsiadm: cannot make connection to 192.168.1.43: No route to host
4.  
5. [Root @ node1 ~] # Iscsiadm-m discovery-t st-p 192.168.1.43 # Test
6. 192.168.1.43: 3260,1 iqn.2015-08.com. feiyu. testsan: 1
7.  
8. [Root @ node1 ~] # Iscsiadm-m node-T iqn.2015-08.com. feiyu. testsan: 1-p 192.168.1.43-l # login node
9. Logging in to [iface: default, target: iqn.2015-08.com. feiyu. testsan: 1, portal: 192.168.1.43, 3260] (multiple)
10. Login to [iface: default, target: iqn.2015-08.com. feiyu. testsan: 1, portal: 192.168.1.43, 3260] successful.
11.  
12. [Root @ node1 ~] # Fdisk-l # a hard disk is added after logon,
13.  
14. Disk/dev/sda: 21.5 GB, 21474836480 bytes
15. 255 heads, 63 sectors/track, 2610 cylinders
16. Units = cylinders of 16065*512 = 8225280 bytes
17. Sector size (logical/physical): 512 bytes/512 bytes
18. I/O size (minimum/optimal): 512 bytes/512 bytes
19. Disk identifier: 0x0006d052
20.  
21. Device Boot Start End Blocks Id System
22. /Dev/sda1*1 39 307200 83 Linux
23. Partition 1 does not end on cylinder boundary.
24. /Dev/sda2 39 2354 18598912 83 Linux
25. /Dev/sda3 2354 2610 2057689 5 Extended
26. /Dev/sda5 2354 2610 2057657 + 83 Linux
27.  
28. Disk/dev/sdc: 10.7 GB, 10742183424 bytes -------> iscsi Device
29. 64 heads, 32 sectors/track, 10244 cylinders
30. Units = cylinders of 2048*512 = 1048576 bytes
31. Sector size (logical/physical): 512 bytes/512 bytes
32. I/O size (minimum/optimal): 512 bytes/512 bytes
33. Disk identifier: 0x00000000

Create a partition for the disk and format it.

1. [Root @ node1 ~] # Mke2fs-t ext4/dev/sdc1

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