while C4 is primary for disk01 and secondary for disk02. If the primary path fails, DMP will switch to the secondary path and the type will show as disabled for the failed path.
15. 通过T3查看 On the T3 -
labt3-1:/:<1>port listmap
port targetid addr_type lun volume owner access u1p1 1 hard 0 v0 u1 primary u1p1 1 hard 1 v1 u1 primary u1p1 1 hard 2 u2v0 u2 failover u1p1 1 hard 3 u2v1 u2 failover u2p1 2 hard 0 v0 u1 failover u2p1 2 hard 1 v1 u1 failover u2p1 2 hard 2 u2v0 u2 primary u2p1 2 hard 3 u2v1 u2 primary
This shows us our LUN ownership and host port target ID's. This is an example of an ES pair in a normal state.
labt3-1:/:<2>port list
port targetid addr_type status host wwn u1p1 1 hard online sun 50020f2300005838 u2p1 2 hard online sun 50020f2300005511
9.关于负载平衡
如果阵列没有两个控制器，且非Active/Active工作方式，（注意：并不是所有厂家的所有阵列都支持这种工作方式）。那么阵列的负载平衡就无法实现。
Depending on the array configuration and running version of Volume Manager,
Active/Active (A/A)
In Active/Active, all sub paths to a disk/lun can be accessed simultaneously. Active/Active allows for load balancing and failover in the event of a path failure. A Sun A5x00 array is an example of an A/A configuration.
Active/Passive - Auto tresspass (A/P)
In Active/Passive, only one of the paths to a disk/LUN can be used at any one time. In the event of an i/o failure on the primary path, i/os will be sent to one of the secondary paths. With an array configured in trespass mode, the failover is invoked by sending the i/os to the second path. Failover is confined to an individual LUN instance level. Active/Passive arrays do not allow load balancing as only one path can be used under normal operating conditions.
Auto trespass is also known as implicit failover.
A Sun T3 array in a single host environment (mp_support=rw) is an example of an A/P - auto-trespass configuration
Active/Passive - Explicit failover (A/PF)
In Active/Passive - explicit failover, only one of the paths (primary) to the disk/LUN can be used at any one time. In the event of an i/o failure, a special command is sent to the array to invoke a failover such that a secondary path can be used. Explicit failover is also known as nonauto-trespass mode.
A Sun T3 array in a multi-host environment (mp_support=std) is an example of an A/PF configuration.
Active/Passive - LUN group failover (A/PG)
In Active/Passive - LUN group failover, a group of one or more LUNs are assigned to a controller on the array, which becomes the primary path to the disks. In the event of an i/o failure to a single LUN, the entire group of LUNs is switched to another controller in the array. This controller becomes the secondary active path. 10.VM的DMP与阵列DMP的结合使用
如果VM的DMP要与阵列的DMP同时使用，请查支持列表，例如HP/CPQ Secure Path 4.0 或EMC PowerPath 3.0.x or ATF，以PKG包的形式存在。
阵列的DMP软件功能是将多路径合并成一条路径，且能实现控制器间的负载均衡。而VM去管理的设备是阵列的DMP软件产生的设备，
通过命令#vxidisk list
emcpower33c simple - - online emcpower38c simple - - online emcpower40c simple - - online emcpower41c simple - - online emcpower42c simple - - online emcpower43c simple - - online emcpower44c simple - - online emcpower45c simple - - online emcpower46c simple - - online emcpower47c simple - - online emcpower48c simple - - online emcpower49c simple - - online emcpower50c simple - - online emcpower51c simple - - online emcpower52c simple - - online
11.一个配置PowerPath的例子
Reconfiguring Solaris Hosts running EMC PowerPath and Veritas VxVM...
For configuration purposes, PowerPath stores a primary and alternate device path in the /kernel/drv/emcpower.conf configuration file, and the Symmetrix device number in stored in the /etc/emcpower_to_volnum file.
Due to hardware reconfiguration, the PowerPath configuration may become invalid for the following reasons:
a) primary and/or alternate hardware address for the underlying device has changed
b) a different volume may be placed behind a hardware address..
The objective of this procedure is to completely reconfigure PowerPath and reimport VxVM disk groups:
Assumptions:
1. emcpower/safe devices are not part of an encapsulated root disk
2. when the hardware configuration is implemented, all the physical disks belonging to the disk groups will still be visible to the host
3. VxVM disk groups are defined on emcpower devices
NOTE: This procedure is to be used only when it is sure that the emcpower devices will be renumbered due to hardware changes.
Do not use this procedure unless you fully understand the situations when it is to be used. Please contact the EMC Customer Support Center should you have any questions.
Obtain a copy of inq version 6.02 or higher as previous versions of inq were not built to see \
SAVE THE CONFIGURATION
1. inq > inq.before - save a copy of the hardware config
2. vxprint -ht > vxprint.ht.out - save a copy of all disk group configurations 3. vxdisk list > vxdisk.list.out - save a copy of each disk and it's associated device 4. for each disk group: vxprint -hvmps -mg
5. Save the above configuration files on a non-PowerPath filesystem
SHUTDOWN AND RECONFIGURE
6. vxdg deport
9. implement the hardware changes
10. boot -rs - reconfigure reboot to reconfigure devices
11. inq - verify that the hardware reconfiguration was successful and that all paths are visible to the host
12. rm /dev/dsk/emcpower* - delete the old emcpower nodes 13. rm /dev/rdsk/emcpower* - delete the old emcpower nodes 14. mv /kernel/drv/emcpower.conf /kernel/drv/emcpower.conf.old 15. mv /etc/emcpower_to_volnum /etc/emcpower_to_volnum.old
16. powercf -q - quietly reconfigure PowerPath. Creates a new emcpower.conf and emcpower_to_volnum.
17. reboot -- -r - reboot reconfigure
MAKE POWERPATH DEVICES VISIBLE TO VERITAS SO THAT AN IMPORT SCAN WILL SUCCEED 18. powervxvm setup - create the /dev/vx/(r)dmp/emcpower nodes 19. vxdctl enable - rescan all the devices on the system
20. powervxvm define - bring the emcpower devices into the VxVM disk list 21. powervxvm online - bring devices with valid private regions online 22. vxdisk list - ensure that all the emcpower devices are \23. vxdg import
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