<\/p>\n
1. The multipath-tools package is not installed as part of a default installation of the operating system. The recommended multipath-tools rpm package is available from the Novell
\nwebsite. The SLES 9 SP3 installation CD includes the multipath-tools package.<\/p>\n
2. Verify that the required version of uDev has been installed for your environment. To query the uDev version, execute the command:<\/p>\n
Also, to prevent significant boot-up delays, edit \/etc\/sysconfig\/boot and set the value: 4. Load the dm_multipath kernel module if it is not already loaded.<\/p>\n Follow the instructions in the annotated multipath.conf file for masking internal scsi disks or disks that need to be excluded from multipath control.<\/p>\n ## This is the \/etc\/multipath.conf file recommended for 6. Perform a dry run and evaluate the setup by running the multipath command.<\/p>\n • With Symmetrix Logical Units, the output will look similar to:<\/p>\n # multipath –v2 -d • With CLARiiON Logical Units, the output will look similar to:<\/p>\n # multipath –v2 –d 7. If the listing is appropriate, commit the configuration as follows.<\/p>\n a. Start the required multipath processes.<\/p>\n • With Symmetrix attach the following modules should be listed:<\/p>\n 8. To get a listing of the current setup do:<\/p>\n • Use of scsi_id based persistent names.<\/p>\n The scsi_id based persistent names are populated under the “\/dev\/disk\/by-name” directory.<\/p>\n • Use of LVM-2 on top of device-mapper.<\/p>\n To enable LVM access to devices that are under multipath control, edit the \/etc\/lvm\/lvm.conf and add “device-mapper” to the “types” extension. By default, device mapper uses the major number of 253.<\/p>\n Configure logical volumes as necessary. LVM based entries in ‘\/etc\/fstab’ are supported. In the normal boot process, the device mapper and the multipath daemons start before LVM starts the discovery process.<\/p>\n You may optionally reboot the host to verify that the required processes automatically startup.<\/p>\n# rpm -q udev<\/code>
\nIf required, upgrade the uDev package and then execute the command to create a new device under the ‘\/dev’ directory.<\/p>\n# udevstart<\/code>
\n3. Novell recommends that ‘subfs’ auto-mount be disabled when using MPIO. This is achieved by editing the ‘\/etc\/sysconfig\/hotplug’ and setting the value:<\/p>\nHOTPLUG_USE_SUBFS=no<\/code><\/p>\n
\nDISABLE_BLKID=yes<\/p>\n# modprobe dm_multipath<\/code>
\n5. Replace the default \/etc\/multipath.conf with the following multipath.conf file recommended by EMC for attach to EMC storage.<\/p>\n
\n## EMC storage devices.
\n##
\n## OS : SLES 9 SP3
\n## Arrays : CLARiiON and SYMMETRIX
\n##
\n## The blacklist is the enumeration of all devices that are to be
\n## excluded from multipath control
\ndevnode_blacklist {
\n## Replace the wwid with the output of the command
\n## ‘scsi_id -g -u -s \/block\/[internal scsi disk name]’
\n## Enumerate the wwid for all internal scsi disks.
\n## Optionally, the wwid of VCM database may also be listed here.
\nwwid 20010b9fd080b7321
\ndevnode “^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*”
\ndevnode “^hd[a-z][[0-9]*]”
\ndevnode “^cciss!c[0-9]d[0-9]*[p[0-9]*]”
\n}
\ndevices {
\n## Device attributes for EMC SYMMETRIX
\ndevice {
\nvendor “EMC “
\nproduct “SYMMETRIX”
\npath_grouping_policy multibus
\ngetuid_callout “\/sbin\/scsi_id -g -u -s \/block\/%n”
\npath_selector “round-robin 0”
\nfeatures “0”
\nhardware_handler “0”
\nfailback immediate
\n}
\n## Device attributes for EMC CLARiiON
\ndevice {
\nvendor “DGC”
\nproduct “*”
\npath_grouping_policy group_by_prio
\ngetuid_callout “\/sbin\/scsi_id -g -u -s \/block\/%n”
\nprio_callout “\/sbin\/mpath_prio_emc \/dev\/%n”
\nhardware_handler “1 emc”
\nfeatures “1 queue_if_no_path”
\nno_path_retry 300
\npath_checker emc_clariion
\nfailback immediate
\n}
\n}<\/p>\n
\ncreate: 360060480000190100501533030383842
\n[size=898 MB][features=”0″][hwhandler=”0″]
\n_ round-robin 0 [prio=4]
\n_ 2:0:2:105 sdaa 65:160 [ready]
\n_ 2:0:3:105 sdas 66:192 [ready]
\n_ 3:0:2:105 sdcj 69:112 [ready]
\n_ 3:0:3:105 sddb 70:144 [ready]
\ncreate: 360060480000190100501533030383843
\n[size=898 MB][features=”0″][hwhandler=”0″]
\n_ round-robin 0 [prio=4]
\n_ 2:0:2:106 sdab 65:176 [ready]
\n_ 2:0:3:106 sdat 66:208 [ready]
\n_ 3:0:2:106 sdck 69:128 [ready]
\n_ 3:0:3:106 sddc 70:160 [ready]
\ncreate: 360060480000190100501533030383844
\n[size=898 MB][features=”0″][hwhandler=”0″]
\n_ round-robin 0 [prio=4]
\n_ 2:0:2:107 sdac 65:192 [ready]
\n_ 2:0:3:107 sdau 66:224 [ready]
\n_ 3:0:2:107 sdcl 69:144 [ready]
\n_ 3:0:3:107 sddd 70:176 [ready]
\ncreate: 360060480000190100501533030383845
\n[size=898 MB][features=”0″][hwhandler=”0″]
\n_ round-robin 0 [prio=4]
\n_ 2:0:2:108 sdad 65:208 [ready]
\n_ 2:0:3:108 sdav 66:240 [ready]
\n_ 3:0:2:108 sdcm 69:160 [ready]
\n_ 3:0:3:108 sdde 70:192 [ready]<\/p>\n
\ncreate: 360060160aa4018002ae6839182a8da11
\n[size=3 GB][features=”1 queue_if_no_path”][hwhandler=”1 emc”]
\n_ round-robin 0 [prio=2]
\n_ 3:0:0:6 sdbe 67:128 [ready]
\n_ 2:0:0:6 sdbk 67:128 [ready]
\n_ round-robin 0
\n_ 3:0:1:6 sdbr 68:80 [ready]
\n_ 2:0:1:6 sdi 8:128 [ready]
\ncreate: 360060160aa4018002ce6839182a8da11
\n[size=3 GB][features=”1 queue_if_no_path”][hwhandler=”1 emc”]
\n_ round-robin 0 [prio=2]
\n_ 3:0:0:7 sdbf 67:144 [ready]
\n_ 2:0:0:7 sdbl 67:128 [ready]
\n_ round-robin 0
\n_ 3:0:1:7 sdbs 68:96 [ready]
\n_ 2:0:1:7 sdj 8:144 [ready]
\ncreate: 360060160aa4018002de6839182a8da11
\n[size=3 GB][features=”1 queue_if_no_path”][hwhandler=”1 emc”]
\n_ round-robin 0 [prio=2]
\n_ 3:0:1:8 sdbt 68:112 [ready]
\n_ 2:0:1:8 sdk 8:160 [ready]
\n_ round-robin 0
\n_ 3:0:0:8 sdbg 67:160 [ready]
\n_ 2:0:0:8 sdbm 67:128 [ready]
\ncreate: 360060160aa4018002ee6839182a8da11
\n[size=3 GB][features=”1 queue_if_no_path”][hwhandler=”1 emc”]
\n_ round-robin 0 [prio=2]
\n_ 3:0:0:9 sdbh 67:176 [ready]
\n_ 2:0:0:9 sdbn 67:128 [ready]
\n_ round-robin 0
\n_ 3:0:1:9 sdbu 68:128 [ready]
\n_ 2:0:1:9 sdl 8:176 [ready]<\/p>\n# \/etc\/init.d\/boot.multipath start
\n# \/etc\/init.d\/multipathd start<\/code>
\nb. Perform an ‘lsmod’ and verify that the processes are running.<\/p>\n# lsmod |grep dm
\ndm_round_robin 20480 1
\ndm_multipath 38544 2 dm_round_robin
\ndm_mod 77536 10 dm_multipath<\/code>
\n• With CLARiiON attach the following modules will be listed:<\/p>\n# lsmod |grep dm
\ndm_emc 10880 1
\ndm_round_robin 7680 1
\ndm_multipath 25352 3 dm_emc,dm_round_robin
\ndm_mod 61312 1 dm_multipath<\/code><\/p>\n# multipath -ll<\/code>
\n9. Integrate the startup of the appropriate daemons in the boot sequence as follows:<\/p>\n# insserv boot.device-mapper multipathd boot.multipath<\/code>
\n10. Device-mapper (dm) names and sd device names may not be persistent across reboots. There are two mechanisms to achieve persistence:<\/p>\ntypes = [ \"device-mapper\", 253 ]<\/code><\/p>\n