SAN & iSCSI

SAN - Storage Area Network, iSCSI - Internet Small Computer System Interface

iSCSI and multipath on CentOS 7

系統環境
設定網路卡

使用指令 nmtui 分別設定兩張網卡的 IP 與 Mask

注意: 這兩張網卡不要作 Bonding。

設定 iSCSI

安裝 iscsi 套件

yum install iscsi-initiator-utils

設定 iscsid.conf: /etc/iscsi/iscsid.conf

# 調整 timeout
#node.session.timeo.replacement_timeout = 120
node.session.timeo.replacement_timeout = 5

# 調整 node 自動 Login
node.startup = automatic

設定 initiator name: /etc/iscsi/initiatorname.iscsi

命名規則可以參考

安裝 multipath 與 netapp_linux_unified_host_utilities
yum install device-mapper-multipath
yum install libhbaapi
rpm -ivh netapp_linux_unified_host_utilities-7-1.x86_64.rpm

如果沒有安裝 libhbaapi,執行 sanlun 會出現錯誤。

連接 iSCSI storage

新增網卡裝置

iscsiadm -m iface -I iscsi_ens2f0 --op=new
iscsiadm -m iface -I iscsi_ens3f0 --op=new

Discovery for the storage

iscsiadm -m discovery -t sendtargets -p <ip-to-iscsi-storage>:3260

如果 NetApp storage 有設置多個 iSCSI IPs,只需要對其中一個 IP 作偵測,輸出結果就會顯示所有 IP。

[root@bdb7-b RPMs]# iscsiadm -m discovery -t sendtargets -p 10.18.104.32:3260
    10.18.104.32:3260,1038 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16
    10.18.104.34:3260,1040 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16
    10.18.104.33:3260,1039 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16
    10.18.104.31:3260,1037 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16
    10.18.104.32:3260,1038 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16
    10.18.104.34:3260,1040 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16
    10.18.104.33:3260,1039 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16
    10.18.104.31:3260,1037 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16

Login nodes

iscsiadm -m node -l all

輸出結果會顯示多行如下資訊

[root@bdb7-b RPMs]# iscsiadm -m node -l all
    Logging in to [iface: iscsi_ens2f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.32,3260] (multiple)
    Logging in to [iface: iscsi_ens3f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.32,3260] (multiple)
    Logging in to [iface: iscsi_ens2f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.34,3260] (multiple)
    Logging in to [iface: iscsi_ens3f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.34,3260] (multiple)
    Logging in to [iface: iscsi_ens2f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.33,3260] (multiple)
    Logging in to [iface: iscsi_ens3f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.33,3260] (multiple)
    Logging in to [iface: iscsi_ens2f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.31,3260] (multiple)
    Logging in to [iface: iscsi_ens3f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.31,3260] (multiple)
    Login to [iface: iscsi_ens2f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.32,3260] successful.
    Login to [iface: iscsi_ens3f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.32,3260] successful.
    Login to [iface: iscsi_ens2f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.34,3260] successful.
    Login to [iface: iscsi_ens3f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.34,3260] successful.
    Login to [iface: iscsi_ens2f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.33,3260] successful.
    Login to [iface: iscsi_ens3f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.33,3260] successful.
    Login to [iface: iscsi_ens2f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.31,3260] successful.
    Login to [iface: iscsi_ens3f0, target: iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16, portal: 10.18.104.31,3260] successful.

使用 sanlun 確認 LUN Disks

[root@bdb7-b RPMs]# sanlun lun show
    controller(7mode/E-Series)/                                  device          host                  lun
    vserver(cDOT/FlashRay)        lun-pathname                   filename        adapter    protocol   size    product
    ---------------------------------------------------------------------------------------------------------------
    TPEDBISCSISVM01               /vol/BDB7_B_4_vol/BDB7_B_4     /dev/sdag       host19     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_4_vol/BDB7_B_4     /dev/sdaf       host20     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_4_vol/BDB7_B_4     /dev/sdae       host17     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_4_vol/BDB7_B_4     /dev/sdad       host18     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_4_vol/BDB7_B_4     /dev/sdac       host16     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_4_vol/BDB7_B_4     /dev/sdab       host15     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_3_vol/BDB7_B_3     /dev/sdz        host20     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_3_vol/BDB7_B_3     /dev/sdaa       host19     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_4_vol/BDB7_B_4     /dev/sdy        host14     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_3_vol/BDB7_B_3     /dev/sdx        host18     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_3_vol/BDB7_B_3     /dev/sdw        host17     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_3_vol/BDB7_B_3     /dev/sdt        host16     iSCSI      500.1g  cDOT
    TPEDBISCSISVM01               /vol/BDB7_B_3_vol/BDB7_B_3     /dev/sdu        host15     iSCSI      500.1g  cDOT
    ...
設定 multipath

初始化後會自動產生設定檔 multipath.conf

mpathconf --enable --with_multipathd y

建立 device alias name 與 LUN WWID 的對應

注意:在 RedHat 7.6 的 multipathd 預設雖然已設定 user_friendly_names yes
    但對於 NetApp 的 LUN disks 仍不會自動建立 mpath X 的磁碟名稱,而只會顯示 WWID,詳細原因請見附檔。
為了爾後方便管理,必須手動建立磁碟名稱與 WWID 對應。

編輯 /etc/multipath.conf , 在檔案最下方新增以下幾行

...
multipaths {
        multipath {
                wwid    3600a0980383136312d3f4e387455564b
                alias   mpath1
        }
        multipath {
                wwid    3600a0980383136312d3f4e387455564c
                alias   mpath2
        }
        multipath {
                wwid    3600a0980383136312d3f4e387455564d
                alias   mpath3
        }
        multipath {
                wwid    3600a0980383136312d3f4e387455564e
                alias   mpath4
        }
}

wwid 可以從指令 multipath -l 取得

alias 可以設定任一名稱,LUN disks的順序可以從指令 sanlun lun show 取得

載入新設定

systemctl reload multipathd

執行 multipath -l,應該要顯示 WWID 與 Alias Name

    mpath2 (3600a0980383136312d3f4e387455564c) dm-5 NETAPP  ,LUN C-Mode
    size=500G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
    |-+- policy='service-time 0' prio=0 status=active
    | |- 12:0:0:1 sdo  8:224  active undef running
    | |- 13:0:0:1 sds  65:32  active undef running
    | |- 15:0:0:1 sdaa 65:160 active undef running
    | `- 16:0:0:1 sdae 65:224 active undef running
    `-+- policy='service-time 0' prio=0 status=enabled
      |- 10:0:0:1 sdg  8:96   active undef running
      |- 11:0:0:1 sdk  8:160  active undef running
      |- 14:0:0:1 sdw  65:96  active undef running
      `- 9:0:0:1  sdc  8:32   active undef running
開機掛載 iSCSI LUNs

注意:若沒有以下設定,將導致系統無法正常開機。

編輯 /etc/fstab , 在 iSCSI disk 每一行都加上 _netdev

#device         mount point     FS      Options Backup  fsck
/dev/myvg/mylv  /mydisk         xfs     _netdev   0      0

設定 netfs 服務自動啟動

## CentOS 7
systemctl enable remote-fs.target

## CentOS 4/5/6
chkconfig netfs on
加大 MTU 設定

網路卡預設 MTU 是 1500,這不適合 iSCSI 的應用,建議加大至 9000。除了 Linux 設定以外,網路連接的 Switch 與 iSCSI Storage (iSCSI Target) 也需要一併做調整。

RedHat 7.x) 檢查目前網路設置是否可接受大 frame 的網路封包傳遞

UNSUCCESSFUL

# ping -M do -c 4 -s  8196 10.1.1.21
PING 10.1.1.21 (10.1.1.21) 8185(8213) bytes of data.
PING 10.1.1.21(10.1.1.21) 8196(8224) bytes of data.
ping: local error: Message too long, mtu=1500
ping: local error: Message too long, mtu=1500

SUCCESSFUL

# ping -M do -c 4 -s 1408 10.1.1.21
PING 10.1.1.21 (10.1.1.21) 1408(1436) bytes of data.
1416 bytes from 10.1.1.21: icmp_seq=1 ttl=58 time=224 ms

立即調整 MTU (NOTE: 非永久性設置)

永久設置方法,在 iSCSI 網路裝置的設定檔 ifcfg-ethXX,加上這行:

MTU="9000"

重啟系統後生效。

擴充新硬碟 LUN disk

1. iSCSI Storage 新增 LUN disk 並分派給要使用的 Linux host。

2. 以下步驟都是 Linux host 要完成的。

3. 掃描(discover)剛剛新增的 LUN disk

[root@bdb7-b ~]# /usr/bin/rescan-scsi-bus.sh
Scanning SCSI subsystem for new devices
Scanning host 0 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
Scanning host 1 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
Scanning host 2 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
Scanning host 3 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
 Scanning for device 3 0 0 0 ...
OLD: Host: scsi3 Channel: 00 Id: 00 Lun: 00
      Vendor: HPE      Model: DVDROM DUD0N     Rev: UMD1
      Type:   CD-ROM                           ANSI SCSI revision: 05
Scanning host 4 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
Scanning host 5 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
Scanning host 6 for  all SCSI target IDs, all LUNs
Scanning host 7 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
 Scanning for device 7 0 0 0 ...

4. 使用 sanlun 指令檢查新 LUN disk

[root@bdb7-b ~]# sanlun lun show all
controller(7mode/E-Series)/                                  device          host                  lun
vserver(cDOT/FlashRay)        lun-pathname                   filename        adapter    protocol   size    product
---------------------------------------------------------------------------------------------------------------
TPEDBISCSISVM01               /vol/BDB7_B_6_vol/BDB7_B_6     /dev/sdaw       host16     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_6_vol/BDB7_B_6     /dev/sdav       host15     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_6_vol/BDB7_B_6     /dev/sdau       host14     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_6_vol/BDB7_B_6     /dev/sdat       host13     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_6_vol/BDB7_B_6     /dev/sdas       host12     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_6_vol/BDB7_B_6     /dev/sdar       host11     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_6_vol/BDB7_B_6     /dev/sdaq       host10     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_6_vol/BDB7_B_6     /dev/sdap       host9      iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_5_vol/BDB7_B_5     /dev/sdao       host15     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_5_vol/BDB7_B_5     /dev/sdan       host16     iSCSI      500.1g  cDOT
TPEDBISCSISVM01               /vol/BDB7_B_4_vol/BDB7_B_4     /dev/sdam       host16     iSCSI      500.1g  cDOT
...

5. 使用 multipath 指令檢查新 LUN disk

[root@bdb7-b alang]# multipath -ll
mpath2 (3600a098038313631305d4e2d6f774744) dm-6 NETAPP  ,LUN C-Mode
size=500G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 9:0:0:1  sdf  8:80   active ready running
| |- 12:0:0:1 sdt  65:48  active ready running
| |- 16:0:0:1 sdah 66:16  active ready running
| `- 15:0:0:1 sdai 66:32  active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 11:0:0:1 sdg  8:96   active ready running
  |- 10:0:0:1 sde  8:64   active ready running
  |- 14:0:0:1 sdu  65:64  active ready running
  `- 13:0:0:1 sdv  65:80  active ready running
mpath1 (3600a098038313631305d4e2d6f774743) dm-5 NETAPP  ,LUN C-Mode
size=500G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 9:0:0:0  sdc  8:32   active ready running
| |- 12:0:0:0 sdr  65:16  active ready running
| |- 16:0:0:0 sdaf 65:240 active ready running
| `- 15:0:0:0 sdag 66:0   active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 11:0:0:0 sdd  8:48   active ready running
  |- 10:0:0:0 sdb  8:16   active ready running
  |- 13:0:0:0 sdq  65:0   active ready running
  `- 14:0:0:0 sds  65:32  active ready running
3600a098038313631305d4e2d6f77474a dm-26 NETAPP  ,LUN C-Mode
size=500G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 9:0:0:5  sdap 66:144 active ready running
| |- 12:0:0:5 sdas 66:192 active ready running
| |- 15:0:0:5 sdav 66:240 active ready running
| `- 16:0:0:5 sdaw 67:0   active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 10:0:0:5 sdaq 66:160 active ready running
  |- 11:0:0:5 sdar 66:176 active ready running
  |- 13:0:0:5 sdat 66:208 active ready running
  `- 14:0:0:5 sdau 66:224 active ready running
...

6. 設定 LUN WWID 與 mpathX 的對應

編輯 /etc/multipath.conf: 將新的 wwid 與 alias 加上。

# added by alang
multipaths {
        multipath {
                wwid    3600a098038313631305d4e2d6f774743
                alias   mpath1
        }
        multipath {
                wwid    3600a098038313631305d4e2d6f774744
                alias   mpath2
        }
        multipath {
                wwid    3600a098038313631305d4e2d6f774745
                alias   mpath3
        }
        multipath {
                wwid    3600a098038313631305d4e2d6f774746
                alias   mpath4
        }
        multipath {
                wwid    3600a098038313631305d4e2d6f774747
                alias   mpath5
        }
        multipath {
                wwid    3600a098038313631305d4e2d6f77474a
                alias   mpath6
        }
}

7. 載入 multipath 設定

[root@bdb7-b alang]# systemctl reload multipathd

[root@bdb7-b alang]# multipath -ll
mpath2 (3600a098038313631305d4e2d6f774744) dm-6 NETAPP  ,LUN C-Mode
size=500G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 12:0:0:1 sdt  65:48  active ready running
| |- 15:0:0:1 sdai 66:32  active ready running
| |- 16:0:0:1 sdah 66:16  active ready running
| `- 9:0:0:1  sdf  8:80   active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 10:0:0:1 sde  8:64   active ready running
  |- 11:0:0:1 sdg  8:96   active ready running
  |- 13:0:0:1 sdv  65:80  active ready running
  `- 14:0:0:1 sdu  65:64  active ready running
mpath1 (3600a098038313631305d4e2d6f774743) dm-5 NETAPP  ,LUN C-Mode
size=500G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 12:0:0:0 sdr  65:16  active ready running
| |- 15:0:0:0 sdag 66:0   active ready running
| |- 16:0:0:0 sdaf 65:240 active ready running
| `- 9:0:0:0  sdc  8:32   active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 10:0:0:0 sdb  8:16   active ready running
  |- 11:0:0:0 sdd  8:48   active ready running
  |- 13:0:0:0 sdq  65:0   active ready running
  `- 14:0:0:0 sds  65:32  active ready running
mpath6 (3600a098038313631305d4e2d6f77474a) dm-26 NETAPP  ,LUN C-Mode
size=500G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 12:0:0:5 sdas 66:192 active ready running
| |- 15:0:0:5 sdav 66:240 active ready running
| |- 16:0:0:5 sdaw 67:0   active ready running
| `- 9:0:0:5  sdap 66:144 active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 10:0:0:5 sdaq 66:160 active ready running
  |- 11:0:0:5 sdar 66:176 active ready running
  |- 13:0:0:5 sdat 66:208 active ready running
  `- 14:0:0:5 sdau 66:224 active ready running

完成。新加的 disk mpath6 可以用 LVM 進行管理。

其他指令

顯示 disk path 更多資訊

[root@bdb7-a ~]# sanlun lun show -p

                    ONTAP Path: TPEDBISCSISVM01:/vol/BDB7_A_2_vol/BDB7_A_2
                           LUN: 1
                      LUN Size: 500.1g
                       Product: cDOT
                   Host Device: mpath2(3600a0980383136312d3f4e387455564c)
              Multipath Policy: service-time 0
            Multipath Provider: Native
--------- ---------- ------- ------------ ----------------------------------------------
host      vserver
path      path       /dev/   host         vserver
state     type       node    adapter      LIF
--------- ---------- ------- ------------ ----------------------------------------------
up        primary    sdo     host12       TPEDBISCSISVM01_iSCSI2
up        primary    sds     host13       TPEDBISCSISVM01_iSCSI2
up        primary    sdaa    host15       TPEDBISCSISVM01_iSCSI1
up        primary    sdae    host16       TPEDBISCSISVM01_iSCSI1
up        secondary  sdg     host10       TPEDBISCSISVM01_iSCSI4
up        secondary  sdk     host11       TPEDBISCSISVM01_iSCSI3
up        secondary  sdw     host14       TPEDBISCSISVM01_iSCSI4
up        secondary  sdc     host9        TPEDBISCSISVM01_iSCSI3

查詢 multipathd 的設定參數資訊

multipathd show config

技巧: 連接不同廠牌的 Storage,預設狀態會套用不同的參數組設定,而這些參數的資訊可以從這指令獲得。

查詢目前 iSCSI connections

# iscsiadm -m session --op show
tcp: [1] 10.18.104.32:3260,1038 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16 (non-flash)
tcp: [2] 10.18.104.33:3260,1039 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16 (non-flash)
tcp: [3] 10.18.104.34:3260,1040 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16 (non-flash)
tcp: [4] 10.18.104.34:3260,1040 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16 (non-flash)
tcp: [5] 10.18.104.33:3260,1039 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16 (non-flash)
tcp: [6] 10.18.104.31:3260,1037 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16 (non-flash)
tcp: [7] 10.18.104.31:3260,1037 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16 (non-flash)
tcp: [8] 10.18.104.32:3260,1038 iqn.1992-08.com.netapp:sn.58042162340f11e9892700a098e3ab45:vs.16 (non-flash)

#iSCSI Logout All
iscsiadm --mode node --logoutall=all

#iSCSI Login All
iscsiadm -m node -l

 

 

 

 

 

 

 

Learning

iSCSI

Multipath on RedHat (NetApp FAS2240)

Multipath 是 CentOS/RedHat 內建套件,可用作兩 port 的 HBA 卡連接 Storage時,有雙路由的備援架構。

系統環境

#>lspci
Fibre Channel: QLogic Corp. ISP2532-based 8Gb Fibre Channel to PCI Express HBA (rev 02)

RedHat 的 HBA Card 驅動

建議安裝方法為,在安裝 RedHat 前先安裝 HBA 卡,然後安裝 RedHat 時會自動驅動 HBA 卡。

如果無法重新安裝 RedHat 試試修改 /etc/modprobe.conf,加上這一行

alias scsi_hostadapter2 qla2500

scsi_hostadapterX 編號視實際狀況修改

查出 HBA 卡的 WWN

#> cat /proc/scsi/qla2xxx/2

SCSI Device Information:
scsi-qla0-adapter-node=5001438004253c81;
scsi-qla0-adapter-port=5001438004253c80; <---- WWN
scsi-qla0-target-0=50001fe1500e28fd;
scsi-qla0-target-1=50001fe1500e28f9;
scsi-qla0-target-2=500a09829140a66c;

另一個 HBA port 裝置檔為 /proc/scsi/qla2xxx/3,以此類推

每個 port 有獨立的 WWN

NetApp storage 分配 LUN 以此 WWN 作為 Host Mapping 的主要參數

驅動後的模組列表

# lsmod | grep qla
    qla2500               209985  0
    qla2xxx               203681  13 qla2500
    scsi_transport_fc      19521  1 qla2xxx
    scsi_mod              153489  7 ib_srp,qla2xxx,scsi_transport_fc,sr_mod,libata,cciss,sd_mo   d

SAN Storge 設定與接線

  1. 將 NetApp storage、SAN switch、RedHat 接上各自的光纖線
  2. 找出 RedHat 的 HBA 卡 兩 port 各自的 WWN
  3. 設定 NetApp,將 LUNs 分配至兩個 WWN Hosts

設定 Multipath

更新:RedHat 客戶中心有提供設定 multipath.conf 線上協助導引,網頁必須先登入才能瀏覽
https://access.redhat.com/labs/multipathhelper/

必要的套件安裝

rpm -q device-mapper
rpm -q device-mapper-multipath
yum install device-mapper
yum install device-mapper-multipath
CentOS 5.x)

編輯 /etc/multipath.conf

# Blacklist all devices by default. Remove this to enable multipathing
# on the default devices.
devnode_blacklist {
#        devnode "*" << 註解這一行
}

## Use user friendly names, instead of using WWIDs as names.
defaults {
        user_friendly_names yes
}

注意:即使啟動了 multipathd 服務,預設是抓不到任何 LUNs 的,必須註解上述的那一行

啟動 multipathd 服務

#> service multipathd start
#> chkconfig multipathd on 
CentOS 6/7)

預設沒有設定檔 /etc/multipath.conf,執行這個指令會自動產生,並且將服務 multipathd 設定成自動執行。

#> mpathconf --enable --with_multipathd y

不用修改 multipath.conf

檢視 multupah 的裝置

CentOS 5.x

[root@cdb3-b ~]# multipath -ll
mpath1 (360a98000383035537824474d3936556a) dm-4 NETAPP,LUN
[size=700G][features=3 queue_if_no_path pg_init_retries 50][hwhandler=0][rw]
\_ round-robin 0 [prio=4][active]
 \_ 1:0:1:0 sdb        8:16  [active][ready]
 \_ 2:0:1:0 sdd        8:48  [active][ready]
\_ round-robin 0 [prio=1][enabled]
 \_ 1:0:0:0 sda        8:0   [active][ready]
 \_ 2:0:0:0 sdc        8:32  [active][ready]

CentOS 6.x

[root@cdb3 ~]# multipath -ll
mpathb (360a98000383035537824474d39365568) dm-2 NETAPP,LUN
size=700G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=4 status=active
| |- 1:0:1:0 sdc 8:32 active ready running
| `- 2:0:1:0 sde 8:64 active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
  |- 1:0:0:0 sdb 8:16 active ready running
  `- 2:0:0:0 sdd 8:48 active ready running

安裝 NetApp 管理工具

*建議*安裝 LUN 管理工具 - NetApp Linux Host Utilities

yum install libnl
rpm -ivh QConvergeConsoleCLI-1.0.01-32.x86_64.rpm
rpm -ivh netapp_linux_host_utilities-6-2.x86_64.rpm

- 如果沒有安裝這套件,將無法使用 sanlun 指令

- 適用 CentOS 5.x/6.x

新增 LUN 需系統重新開機

一旦重新開機後,所有的 LUN disks (在 dual path SAN 架構下會有多個 LUN disks)應該都會被偵測到,並且會有一個 mpathXX 的裝置名稱。

#> multipath -l
mpath1 (360a98000424732615124444150534a35)
[size=100 GB][features="1 queue_if_no_path"][hwhandler="0"]
\_ round-robin 0 [active]
 \_ 2:0:2:0 sde 8:64 [active]
 \_ 3:0:2:0 sdf 8:80 [active]

mpath0 (3600508b400068e5c00012000001a0000)
[size=100 GB][features="1 queue_if_no_path"][hwhandler="0"]
\_ round-robin 0 [active]
 \_ 2:0:0:1 sda 8:0  [active]
 \_ 3:0:0:1 sdc 8:32 [active]
\_ round-robin 0 [enabled]
 \_ 2:0:1:1 sdb 8:16 [active]
 \_ 3:0:1:1 sdd 8:48 [active]

mpathX 這路徑可作為 LVM 的 PV 或直接格式化為 filesystem,完整路徑為 /dev/mapper/mpathX

2:0:0:1 這表示為 host : channel : ID : LUN

Host 2 與 Host 3 表示 HBA 卡有兩個 port 或者單 port 的卡兩張

新增/移除 LUN 系統不需重開機

參考教學:

CentOS/RedHat 5.x 以後

從 CentOS/RedHat 5 以後或者 SLES 10 以後,可以安裝以下套件:

yum install sg3_utils

不停機下掃描新的 LUN Disk

檢視目前現有的 LUN Disks
#> sanlun lun show all

掃描所有 LUN
#> scsi-rescan
NOTE: 如果偵測不到新 LUN,試試加上 -a
#> scsi-rescan -a

再次檢視目前的 LUN Disks
#> sanlun lun show all

移除 LUN 的程序

要移除現有的 LUN disk 必須依照以下步驟完成:

  1. 執行 umount 卸載
  2. 執行 lvremove 移除 LV
  3. 需要時,執行 vgremove 移除 VG
  4. 執行 pvremove 移除 PV
  5. 執行 multipath -f mpathXX 移除 multipathXX
    NOTE: 如果沒有執行這步驟,一旦移除 LUN 後系統可能會 Hang。
  6. 從 Storage 管理介面移除這個 LUN disk
    NOTE: 當 LUN 被移除後,執行 sanlun lun show all,那些移除的 LUN 會顯示 unknown。
  7. 執行 scsi-rescan -r 移除所有未使用的 LUN disk
    NOTE: 執行後輸出訊息,應該要顯示類似
    4 device(s) removed.
    [5:0:1:0]
    [5:0:3:0]
    [6:0:1:0]
    [6:0:3:0]
    重新執行 sanlun lun show all,那些 unknown 就會消失。
CentOS/RedHat 4.x:

使用附檔區的兩個 script

  1. remove-LUNs.sh
  2. rescan-LUNs.sh

新增 LUN disk 步驟

  1. 在 NetApp storage 上完成 LUN Mapping 的設定
  2. 在 RedHat 上執行 rescan-LUNs.sh
  3. 在 RedHat 上執行 multipath -l

移除現有 LUN disk

  1. 在 RedHat 上卸載不用的 mpathX
  2. 在 RedHat 上執行 sanlun lun show all 找出 LUN 的名稱與 NetApp 上路徑
    註:要執行 sanlun 指令必須先安裝 NetApp 的套件 netapp_linux_host_utilities-6-2.x86_64.rpm
  3. 在 NetApp 上移除所對應的 LUN
  4. 在 RedHat 上執行 multipath -l
  5. 找出要移除 LUN disks 的 host:channel:id:LUN
  6. 執行 remove-LUNs.sh <host> <channel> <id> <LUN>

現有 LUN disk 擴充空間

1. 確認 LUN ID 與 sd[X] 的對應

smartctl -a /dev/sd[X]

2. 掃描 LUN disk,確認最新容量

echo 1 > /sys/block/sd[X]/device/rescan

lsblk | grep sd[X]

3. Resize PV

pvresize /dev/sd[X]

4. 完成。接著就按 SOP 進行 LV 與 Filesystem 的擴充。

LVM 管理

新增 LUN disk 成一個 PV

#> pvcreate /dev/mapper/mpath6

PV 新增後,執行 pvdisplay 時的裝置名稱會是 dm-X。

新增一個 VG (需指定 PV)

#> vgcreate dbVG /dev/mapper/mpath6

指令更多用法

multipath

/etc/init.d/multipathd start Manually starts the multipathing service on the Linux host.
multipath -ll Displays the multipathing configuration.
multipath -v2 Creates the initial multipathing configuration.
multipath -f device_map Removes an existing LUN from the multipathing configuration.
multipath -ll -v2 -d Displays the multipathing configuration in verbose mode.
multipath -t 或 multipathd show config 顯示目前的設定參數

Accesing LUNs on host

sanlun fcp show adapter -v Displays HBA information.
sanlun fcp show adapter Display WWPN of HBA cards
sanlun lun show all Lists available LUNs as seen by the sanlun script.
sanlun lun show -p Provides multipath information for both DM-Multipath and Veritas
Storage Foundation
TM
dynamic multipathing solutions.
ls -lh /dev/mapper/ Lists DM-Multipath devices generated for LUNs.
e2label device label Creates a persistent label for a file system. device is the partition; label
is a unique string up to 16 characters. Not needed with DM-Multipath.

Q & A

Q: RHEL 7 沒有使用 alias path

使用 NetApp Storage,執行 multipath -ll

    360a98000443437576f2444726e556d76 dm-2 NETAPP  ,LUN
    size=800G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
    |-+- policy='service-time 0' prio=50 status=active
    | `- 6:0:0:0 sdb 8:16 active ready running
    `-+- policy='service-time 0' prio=10 status=enabled
      `- 6:0:3:0 sdc 8:32 active ready running

    不會顯示 alias name: mpathXX

參閱官方手冊:https://access.redhat.com/solutions/2061463

檢視 multipath 可支援的裝置清單

multipath -t

沒有看到 NetApp 的裝置。

解決方法:編輯 multipath.conf,加入 NetApp 的參數設定

NOTE: 僅適合 NetApp Storage。

defaults {
user_friendly_names yes
find_multipaths yes
}

devices {
device {
vendor "NETAPP"
product "LUN.*"
path_grouping_policy "group_by_prio"
path_checker "tur"
features "3 queue_if_no_path pg_init_retries 50"
hardware_handler "0"
prio "ontap"
failback immediate
rr_weight "uniform"
rr_min_io 128
flush_on_last_del "yes"
dev_loss_tmo "infinity"
user_friendly_names yes
retain_attached_hw_handler yes
detect_prio yes
}

載入新設定

#> systemctl reload multipathd

#> multipath -ll
mpatha (360a98000443437576f2444726e556d76) dm-2 NETAPP ,LUN
size=800G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 4:0:0:0 sdb 8:16 active ready running
| `- 6:0:0:0 sdd 8:48 active ready running
`-+- policy='service-time 0' prio=10 status=enabled
|- 4:0:3:0 sdc 8:32 active ready running
`- 6:0:3:0 sde 8:64 active ready running
Q: 安裝 netapp_linux_host_utilities 時,出現錯誤訊息

Warning: libnl.so library not found, some sanlun commands may not work. Refer Li nux Host Utilities Installation and Set up Guide for more details
    Warning: libHBAAPI.so library not found, some sanlun commands may not work. Refe r Linux Host Utilities Installation and Setup Guide for more details

Solution: 先安裝 libnl

yum install libnl

再安裝以下套件任一個

Q: 執行 pvscan、vgscan 或開機時出現以下訊息

Found duplicate PV XXXXXXXXXXXXXXXX: using /dev/sdb not /dev/sda

Solution: 

這通常會發生在系統有作 multipath 與 LVM 設定後,原因是 CentOS 4/5 預設 LVM 的設定會掃描所有的磁碟裝置,然而,當系統設定有 multipath 時,LVM 應該管理 mpathX 或 dm-X 的裝置,而不再是 sdX 裝置。

要使 LVM 不再對 sdX 裝置作管理,可以修改 /etc/lvm/lvm.conf,此外,如果要使每次系統開機時,LVM 不要對 sdX 裝置作掃描,還必須要重建 initrd 開機映像檔,並且修改 grub.conf 相關的設定。

操作步驟如下:

1. 編輯 /etc/lvm/lvm.conf

...
filter = [ "r|/dev/sd.*|", "a|/.*|" ]
...

r|/dev/sd.*| 這設定會排除所有 sda, sdb, ...等所有磁碟裝置掃描,如果系統有使用其中某個裝置,必須自行修改這規則。

存檔離開

執行 pvscan 或 vgscan,如果不再出現 Warning,繼續步驟 2。

2. 重建 initrd 開機映像檔

#> cd /boot
#> mkinitrd -f -v /boot/initrd-$(uname -r).multipath.img $(uname -r)

編輯 /boot/grub/grub.conf
複製 title 段落的所有行,並依照實際狀況修改

title CentOS (2.6.18-398.el5-Multipath)                      <== 加上 Multipath
root (hd0,0)
kernel /vmlinuz-2.6.18-398..........
initrd /initrd-2.6.18-398.el5.multipath.img <== 重建後的initrd 開機映像檔名

存檔離開

3. 重新開機後,出現開機選單後,選擇第二個開機項目。

如果開機訊息不再出現警告文字,而且系統一切正常,就可以再修改 grub.conf 的 default=1。