Emc powerpath devices can still be configured as foreign devices in vxvm 4. Verify multiple paths using below commands once youve installed emc powerpath, execute powermt display devall as shown below to verify whether multiple paths as displayed accordingly. However i have now recieved the final production server and need to set this all up again. As gurutc says, the powerpath psuedo device names should remain static. This is not a blocking issue since native devices can be used under the format command instead of the pseudo device. Emc powerpath powermt command examples ramesh peram. We can say that the lun is mapped with the pseudo name at the host. List available powerpath pseudo device nameslist used powerpath pseudo device names or rename powerpath pseudo device. Emc powerpath powermt command examples if your server has two hba cards connected to emc san storage device, you can implement loadbalancing, and failover on the hba cards using the emc powerpath software. Server considerations deployment best practices for. Since powerpath and the thirdparty software cannot comanage devices, do not initiate comanagement by executing this command if this software is present support for this array type is disabled in powerpath hdlm hitachi lightning, hitachi tagmastore devices, do not initiate comanagement by executing this command if this software is present support for this. After doing powermt config, the pseudo devices for my new luns appear on format like this. Emc powerpath powermt command examples aix,solaris,hp. In this post we will cover how to install, license and scan for newly attached storage.
Download the powerpath software from emc powerlink website. Part of the unix paradigm is that everything is a file and programs can use file operations read andor write to interact with the system, so to load up randomness for crypto functions, you do a file read on devrandom or devurandom which connects you to the rng. On the lspv output i noticed 4 of 8 hdiskpower devices without pvids those pvids are now seen on plane emcs hdisk devices. In the following example, emc powerpath 5 emcpower. How to install and configure emc powerpath on linux. Mar 27, 2019 some daemon is still keeping the pseudo device andor its native paths open. Server considerations deployment best practices for oracle. Aix and powerpath issue emc symmetrix aix forum forum. If powerpath is installed and configured correctly, then it will fail over, whether or not you have the alternate path set up with pv links.
But due to this activity the mapping between pseudo name and logical device id changed due to unknown reason. Either powerpath of the native fcnvme multipath software should be configured and present the devices using pseudo device names for example, devemcpowera when using powerpath, or devnvme0n1 when using native fcnvme multipath. Oct 03, 2016 before starting with the procedure to replace the pseudo devices, lets have a look at what is a pseudo device name. Since powerpath and the third party software cannot co. This driver software creates a single pseudo device for a given array volume lun regardless of how many physical paths on which it appears. I do understand the concept of they not being physically present.
If your server has two hba cards connected to emc san storage device, you can implement loadbalancing, and failover on the hba cards using the emc powerpath software powermt management utility helps you manage io paths from the server to the emc storage device. This software allows one to map the os devices to a pseudo block device without having to worry about the device paths. Identification and versioning on the unix platform. While seeing the lun, you will not see its name but will see the. Mar 15, 2019 powerpath is emc licensed software for managing san attached storage on your systems. The problems that youre experiencing suggest that you have a connectivity issue, so there are a few things to check. List all used powerpath pseudo device names with corresponding instance numbers. Some daemon is still keeping the pseudo device andor its native paths open. Dec 05, 2012 emc powerpath is one of the best multipathing software that is used on the servers and not only it is stable but it is very easy to use, today i would like to show how to install it and to change the pseudo device name, sometimes when you are working on server where the luns are shared you want the device name to be same so that you can find them easily and sometime make your troubleshooting. Using emc powerpath devices with vxvm in previous versions of vxvm, it was necessary to perform powervxvm init and powervxvm online to use emc powerpath devices with vxfas in vxvm 4. If you are not installing powerpath software then reboot the server. In tku july 2008 an additional pattern was added to the module that enables identification of emc powerpath on the unix solaris and linux at this stage platform. What can change however, is the devsd devices that make up the pseudo device. The following sections describe procedures for using powerpath pseudo emcpower devices with vxfas.
Emc powerpath is a software designed for load balancing, path management, and device management. Boot lun is on san hitachi, in gold image we are with powerpath, but hitachi wants us to go for multipath only. Since powerpath and the thirdparty software cannot comanage devices, do not initiate comanagement by executing this command if this software is present support for this array type is disabled in powerpath hdlm hitachi lightning, hitachi tagmastore. But then i check in powermt display devall i see all hdiskpower devices with complete number of paths corresponding hdiskx devices. As soon as the powerpath services were started, the device mapping config changed. Now we were left with a situation where the older devemcpowera device was actually mapped to devemcpowerc. Now i needs to export the rootvg which is again not possible in normal circumstance before uninstall the powerpath software and reboot the server with multipath such as external devices will come up with multipath device. The powerpath pseudo device naming convention and therefore the device permission is the same, regardless of whether you are using fc or fcnvme. Troubleshooting powerpath on page 95 for procedures to resolve problems while installing and administering powerpath. Installing powerpath and changing the emc pseudo device name.
Backup and protection storage backup and protection software shop all data protection products. Emc powerpath powermt command windows administrators blog. Getting the powerpath to work is a huge problem, and i am trying to determine what the best course of action. But what i do not understand is the need of having such files. Nov 18, 2008 this software allows one to map the os devices to a pseudo block device without having to worry about the device paths. Emc powerpath not creating hdiskpower devices i have an aix 5. To find out what devices are configured under powerpath, issue a powermt display devall command. Separate pattern was created due to the significant difference in the way the product is identified on the windows and unix platforms. Emc powerpath multipathing automatically tunes your storage area network san and selects alternate paths for your data if necessary. Mapping between pseudo name and logical device id in. If youve purchased emc support, you should have access to powerlink. Powerpath powermt commands emc unix knowledge base. I have installed powerpath and was expecting to see hdiskpower emc devices for powerpath, but powerpath doesnt create hdiskpower devices. I have configured powerpath to have the pseudo devices for my luns in server.
Power path installation and config in linux servers. Would someone be kind enough to define pseudo and native devices where ppme is concerned please. When powerpath tries to configure the pseudo device, it needs to open all the paths. It was taling over 20 minutes to complete a rescan because it was parsing all those devices. At the heart of powerpath ve path management is serverresident software inserted between the scsi device driver layer and the rest of the operating system. Multipath io is a faulttolerance and performance enhancement technique in computer storage area networks, whereby there is more than one physical path between the cpu in a computer storage system. List available powerpath pseudo device namesused pseudo device names rename powerpath pseudo device. Change the pseudo device name emcpower in powerpath. In the case of hdisk3,the open fails because the device is hold by asm. How to migrate from powerpath to multipath boot lun is on. Powerpath just keeps track of opens sent down from the userland to determine if any process or processes is using a device and if any opens are active, then powerpath will not allow to remove the device from its control.
Also, in what kinda of applications will pseudo device files be helpful. Running powermt display devall will show you which devsd devices are associated with each of your pseudo devices. Emc powerpath on solaris linux administration blog. Now i needs to export the rootvg which is again not possible in normal circumstance before uninstall the powerpath software and reboot the server with multipath such as external devices will come up with multipathdevice. This happened as emc powerpath software assigned the pseudo device ids based on the new device config as recognized by os and without noticing the. Upgrading powerpath on page 69 for prerequisites and procedures to upgrade powerpath. That isnt really a problem so long as you make sure to use the pseudo device name rather than the underlying real names. Powermt management utility helps you manage io paths from the server to the emc storage device. Since this server is using powerpath, i have four devices, all with the same uuid sda, sdb, sdc and sdd. This happened as emc powerpath software assigned the pseudo device ids based on the new device config as recognized by os and without noticing the difference, they issued powermt config.
Hi, i migrated data from our dmx to our clarion and would like to reclaim the dmx luns. How to migrate from powerpath to multipath boot lun is on san. Powermax fcnvme deployment with linux part ii setup. Start navisphere, right click on the array serial number and select connectivity status from the menu. One way to recover from such a scenario would have been to copy the device config from the good node to this node. The physical multipath is through the buses, controllers, switches. Emc lun to device mapping solutions experts exchange. In this article, let us discuss how to use powermt command with practical examples. If underlying singlepath devices are not filtered out, lvm discovers, thus reports the duplicate device paths that all reference the same lvm device. At the heart of powerpathve path management is serverresident software inserted between the scsi devicedriver layer and the rest of the operating system. Residing on the server, powerpath multipathing enhances san performance and application availability.
Since powerpath and the third party software cannot co manage. The issue i am having is that no matter what i do, power path see the luns as active and alive. Hello emc community, i have a doubt that maybe some of you have already figured out. It also integrates multiplepath io capabilities, automatic load balancing, and path failover functions for complete. I once reinstalled the powerpath and found that the pseudo names are changing. I have a backup software that requires that all the devices presented in linux to have different uuid. Emc powerpath how to change psuedo names using powermt. Linux device mapper example fc only when you use device mapper, there are multiple ways for you to set pseudo device names or aliases. I want to keep the device to pseudo name mapping intact even after reinstalling the powerpath software. Powerpath is emc licensed software for managing san attached storage on your systems. Before starting with the procedure to replace the pseudo devices, lets have a look at what is a pseudo device name. The physical multipath is through the buses, controllers, switches, and bridge devices connecting the mass storage. A pseudo device name is automatically assigned to the lun when powerpath is configured.
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