在RHEL 5上搭建ISCSI TARGET

通过安装Openfiler或者FreeNAS软件，我们可以很方便地将闲置的PC机变废为宝为存储服务器，其中还提供了ISCSI TARGET服务。但很多情况下我们用不到Openfiler的那么多功能(包括NFS,CIFS等等)，同时又希望这台"存储服务器"能扮演更多的角色(例如作为DataGurad的备库或者作为Netbackup备份服务器)，这时Openfiler就无法满足我们了。何不手动来搭建能够基本满足需求的ISCSI服务呢？

/* 首先我们需要一台已安装了RHEL5或者OEL5的服务器，同时已安装了scsi-target-utils包 */

[root@rh3 dsk]# hostname
rh3.oracle.com

[root@rh3 ~]# rpm -qa|grep scsi-target-utils
scsi-target-utils-0.0-6.20091205snap.el5_4.1

/* 创建ISCSI服务映射的磁盘文件 */

[root@rh3 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              48G  3.5G   42G   8% /
/dev/sda2              95G  188M   90G   1% /s01
tmpfs                 1.3G     0  1.3G   0% /dev/shm
none                  1.3G  104K  1.3G   1% /var/lib/xenstored
/dev/sda4             145G   21G  117G  15% /dsk

[root@rh3 ~]# for i in 1 2 3 4 5 6 7 8 9 10
> do
> dd if=/dev/zero of=/dsk/disk$i.dat bs=1024k count=2048
> done

2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 14.9789 seconds, 143 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 28.8623 seconds, 74.4 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 29.6608 seconds, 72.4 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 36.735 seconds, 58.5 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 28.9802 seconds, 74.1 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 28.5747 seconds, 75.2 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 37.6903 seconds, 57.0 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 26.4861 seconds, 81.1 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 38.151 seconds, 56.3 MB/s
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 31.2119 seconds, 68.8 MB/s

/* 以上在/dsk目录下建立了10个大小为2G的磁盘文件 */

[root@rh3 ~]# service tgtd start
Starting SCSI target daemon: Starting target framework daemon

[root@rh3 dsk]# chkconfig tgtd on

/* 新建iscsi target */

[root@rh3 ~]# tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.2010-10.com.rh-cluster.nas

/* 启动相关tgtd 服务 */

[root@rh3 dsk]# tgtadm --lld iscsi -o show -m target
Target 1: iqn.2010-010.com.rh-cluster.nas
    System information:
        Driver: iscsi
        State: ready
    I_T nexus information:
    LUN information:
        LUN: 0
            Type: controller
            SCSI ID: IET     00010000
            SCSI SN: beaf10
            Size: 0 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: None
    Account information:
    ACL information:

/* 进一步验证TARGET添加成功 */

[root@rh3 dsk]# for i in 1 2 3 4 5 6 7 8 9 10
> do
> tgtadm --lld iscsi -o new -m logicalunit --tid 1 --lun $i -b /dsk/disk$i.dat
> done

/* 将10个虚拟磁盘添加到TARGET */

[root@rh3 dsk]# tgtadm --lld iscsi -o show -m target
Target 1: iqn.2010-010.com.rh-cluster.nas
    System information:
        Driver: iscsi
        State: ready
    I_T nexus information:
    LUN information:
        LUN: 0
            Type: controller
            SCSI ID: IET     00010000
            SCSI SN: beaf10
            Size: 0 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: None
        LUN: 1
            Type: disk
            SCSI ID: IET     00010001
            SCSI SN: beaf11
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk1.dat
        LUN: 2
            Type: disk
            SCSI ID: IET     00010002
            SCSI SN: beaf12
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk2.dat
        LUN: 3
            Type: disk
            SCSI ID: IET     00010003
            SCSI SN: beaf13
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk3.dat
        LUN: 4
            Type: disk
            SCSI ID: IET     00010004
            SCSI SN: beaf14
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk4.dat
        LUN: 5
            Type: disk
            SCSI ID: IET     00010005
            SCSI SN: beaf15
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk5.dat
        LUN: 6
            Type: disk
            SCSI ID: IET     00010006
            SCSI SN: beaf16
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk6.dat
        LUN: 7
            Type: disk
            SCSI ID: IET     00010007
            SCSI SN: beaf17
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk7.dat
        LUN: 8
            Type: disk
            SCSI ID: IET     00010008
            SCSI SN: beaf18
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk8.dat
        LUN: 9
            Type: disk
            SCSI ID: IET     00010009
            SCSI SN: beaf19
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk9.dat
        LUN: 10
            Type: disk
            SCSI ID: IET     0001000a
            SCSI SN: beaf110
            Size: 2147 MB
            Online: Yes
            Removable media: No
            Backing store type: rdwr
            Backing store path: /dsk/disk10.dat
    Account information:
    ACL information:

/* 验证磁盘是否正确添加 */

[root@rh3 dsk]# tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL

/*  绑定ip地址为ALL，即所有主机均可访问该ISCSI资源 */

/* 至此iscsi的server端配置完成，我们切换到客户端主机上进行配置 */

[root@rh2 ~]# hostname
rh2

[root@rh2 ~]# rpm -qa|grep iscsi
iscsi-initiator-utils-6.2.0.871-0.16.el5

/* 要求客户端主机上已安装iscsi-initiator-utils rpm包*/ 

[root@rh2 iscsi]# service iscsi start
iscsid 已死，但 pid 文件仍存
Starting iSCSI daemon:                                     [确定]
                                                           [确定]
设置 iSCSI 目标：iscsiadm: No records found!
                                                           [确定]

/* 启动iscsi服务 */

[root@rh2 iscsi]# iscsiadm -m discovery -t sendtargets -p rh3.oracle.com
192.168.1.108:3260,1 iqn.2010-010.com.rh-cluster.nas

/* 在客户端尝试发现远程主机上的iscsi target */

[root@rh2 iscsi]# service iscsi restart
Stopping iSCSI daemon:
iscsid 已死，但 pid 文件仍存                               [确定]
Starting iSCSI daemon:                                     [确定]
                                                           [确定]
设置 iSCSI 目标：Logging in to [iface: default, target: iqn.2010-010.com.rh-cluster.nas, portal: 192.168.1.108,3260]
Login to [iface: default, target: iqn.2010-010.com.rh-cluster.nas, portal: 192.168.1.108,3260]: successful
                                                           [确定]

/* 重启本地的iscsi服务，该服务正确登录到了rh3.oracle.com 3260端口上的iscsi target */

[root@rh2 ~]# tail -88 /var/log/messages
Oct 25 20:24:35 rh2 kernel: sde: Write Protect is off
Oct 25 20:24:35 rh2 kernel: SCSI device sde: drive cache: write back
Oct 25 20:24:35 rh2 kernel: SCSI device sde: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:35 rh2 kernel: sde: Write Protect is off
Oct 25 20:24:35 rh2 kernel: SCSI device sde: drive cache: write back
Oct 25 20:24:35 rh2 kernel:  sde: unknown partition table
Oct 25 20:24:35 rh2 kernel: sd 5:0:0:3: Attached scsi disk sde
Oct 25 20:24:35 rh2 kernel: sd 5:0:0:3: Attached scsi generic sg5 type 0
Oct 25 20:24:35 rh2 kernel:   Vendor: IET       Model: VIRTUAL-DISK      Rev: 0001
Oct 25 20:24:35 rh2 kernel:   Type:   Direct-Access                      ANSI SCSI revision: 05
Oct 25 20:24:35 rh2 kernel: SCSI device sdf: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:35 rh2 kernel: sdf: Write Protect is off
Oct 25 20:24:35 rh2 kernel: SCSI device sdf: drive cache: write back
Oct 25 20:24:35 rh2 kernel: SCSI device sdf: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:35 rh2 kernel: sdf: Write Protect is off
Oct 25 20:24:35 rh2 kernel: SCSI device sdf: drive cache: write back
Oct 25 20:24:35 rh2 kernel:  sdf: unknown partition table
Oct 25 20:24:35 rh2 kernel: sd 5:0:0:4: Attached scsi disk sdf
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:4: Attached scsi generic sg6 type 0
Oct 25 20:24:36 rh2 kernel:   Vendor: IET       Model: VIRTUAL-DISK      Rev: 0001
Oct 25 20:24:36 rh2 kernel:   Type:   Direct-Access                      ANSI SCSI revision: 05
Oct 25 20:24:36 rh2 kernel: SCSI device sdg: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdg: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdg: drive cache: write back
Oct 25 20:24:36 rh2 kernel: SCSI device sdg: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdg: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdg: drive cache: write back
Oct 25 20:24:36 rh2 kernel:  sdg: unknown partition table
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:5: Attached scsi disk sdg
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:5: Attached scsi generic sg7 type 0
Oct 25 20:24:36 rh2 kernel:   Vendor: IET       Model: VIRTUAL-DISK      Rev: 0001
Oct 25 20:24:36 rh2 kernel:   Type:   Direct-Access                      ANSI SCSI revision: 05
Oct 25 20:24:36 rh2 kernel: SCSI device sdh: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdh: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdh: drive cache: write back
Oct 25 20:24:36 rh2 kernel: SCSI device sdh: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdh: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdh: drive cache: write back
Oct 25 20:24:36 rh2 kernel:  sdh: unknown partition table
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:6: Attached scsi disk sdh
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:6: Attached scsi generic sg8 type 0
Oct 25 20:24:36 rh2 kernel:   Vendor: IET       Model: VIRTUAL-DISK      Rev: 0001
Oct 25 20:24:36 rh2 kernel:   Type:   Direct-Access                      ANSI SCSI revision: 05
Oct 25 20:24:36 rh2 kernel: SCSI device sdi: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdi: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdi: drive cache: write back
Oct 25 20:24:36 rh2 kernel: SCSI device sdi: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdi: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdi: drive cache: write back
Oct 25 20:24:36 rh2 kernel:  sdi: unknown partition table
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:7: Attached scsi disk sdi
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:7: Attached scsi generic sg9 type 0
Oct 25 20:24:36 rh2 kernel:   Vendor: IET       Model: VIRTUAL-DISK      Rev: 0001
Oct 25 20:24:36 rh2 kernel:   Type:   Direct-Access                      ANSI SCSI revision: 05
Oct 25 20:24:36 rh2 kernel: SCSI device sdj: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdj: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdj: drive cache: write back
Oct 25 20:24:36 rh2 kernel: SCSI device sdj: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdj: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdj: drive cache: write back
Oct 25 20:24:36 rh2 kernel:  sdj: unknown partition table
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:8: Attached scsi disk sdj
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:8: Attached scsi generic sg10 type 0
Oct 25 20:24:36 rh2 kernel:   Vendor: IET       Model: VIRTUAL-DISK      Rev: 0001
Oct 25 20:24:36 rh2 kernel:   Type:   Direct-Access                      ANSI SCSI revision: 05
Oct 25 20:24:36 rh2 kernel: SCSI device sdk: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdk: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdk: drive cache: write back
Oct 25 20:24:36 rh2 kernel: SCSI device sdk: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdk: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdk: drive cache: write back
Oct 25 20:24:36 rh2 kernel:  sdk: unknown partition table
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:9: Attached scsi disk sdk
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:9: Attached scsi generic sg11 type 0
Oct 25 20:24:36 rh2 kernel:   Vendor: IET       Model: VIRTUAL-DISK      Rev: 0001
Oct 25 20:24:36 rh2 kernel:   Type:   Direct-Access                      ANSI SCSI revision: 05
Oct 25 20:24:36 rh2 kernel: SCSI device sdl: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdl: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdl: drive cache: write back
Oct 25 20:24:36 rh2 kernel: SCSI device sdl: 4194304 512-byte hdwr sectors (2147 MB)
Oct 25 20:24:36 rh2 kernel: sdl: Write Protect is off
Oct 25 20:24:36 rh2 kernel: SCSI device sdl: drive cache: write back
Oct 25 20:24:36 rh2 kernel:  sdl: unknown partition table
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:10: Attached scsi disk sdl
Oct 25 20:24:36 rh2 kernel: sd 5:0:0:10: Attached scsi generic sg12 type 0
Oct 25 20:24:36 rh2 iscsid: transport class version 2.0-871. iscsid version 2.0-871
Oct 25 20:24:36 rh2 iscsid: iSCSI daemon with pid=4907 started!
Oct 25 20:24:36 rh2 iscsid: connection1:0 is operational now

/* 从rh2主机上的系统日志可以看到Linux正确识别了iscsi目标附带的虚拟磁盘 */

[root@rh2 ~]# cat /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: WDC WD3200AAJS-0 Rev: 01.0
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi3 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: Hitachi HCS72101 Rev: JP4O
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 00
  Vendor: IET      Model: Controller       Rev: 0001
  Type:   RAID                             ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 01
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 02
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 03
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 04
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 05
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 06
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 07
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 08
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 09
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 10
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0001
  Type:   Direct-Access                    ANSI SCSI revision: 05

/* 共有10个VIRTUAL-DISK */

[root@rh2 ~]# hdparm -tT /dev/sdl

/dev/sdl:
 Timing cached reads:   9228 MB in  2.00 seconds = 4620.43 MB/sec
 Timing buffered disk reads:  148 MB in  3.03 seconds =  48.77 MB/sec
[root@rh2 ~]# hdparm -tT /dev/sdl

/dev/sdl:
 Timing cached reads:   9556 MB in  2.00 seconds = 4782.39 MB/sec
 Timing buffered disk reads:  170 MB in  3.01 seconds =  56.47 MB/sec
[root@rh2 ~]# hdparm -tT /dev/sdl

/dev/sdl:
 Timing cached reads:   9620 MB in  2.00 seconds = 4814.14 MB/sec
 Timing buffered disk reads:  178 MB in  3.02 seconds =  59.00 MB/sec
[root@rh2 ~]# hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   9368 MB in  2.00 seconds = 4685.71 MB/sec
 Timing buffered disk reads:  306 MB in  3.01 seconds = 101.58 MB/sec

/* 实际测试磁盘速度发现，千兆网络条件下虚拟磁盘的读取速度大约在50-59MB，缓存读取(cached reads)则和普通磁盘大致相仿 */