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Red Hat / RHEL 5.x 6.x & PowerPath
Is there any doucmentation other than this for for someone who runs RHEL boxes and wants to use PowerPath?
EMC ® PowerPath ® for Linux
Version 5.7
Installation and Administration Guide
P/N 300-014-166
REV 02
I am completely boot to san. I have a few existing systems that are LVM, never had the native multipathing configured, and have had PowerPath installed.
I also have a handful of systems that are boot to san where the native multipath driver is in use. I prefer this becuase I know how to configure multipathd and make it work. Powerpath for Linux is a huge headache for me.
I have searched the forums and the internet. I can find 5 or 6 different blogs that have some notes or tips on installing RH and using powerpath, but every one has a completely different set of instructions to install a new system... I have dealt with my sales team and support engineers. Getting someone who knows how Linux works with Powerpath is nearly impossible.
I've never gotten an answer from anyone at EMC about how to make powerpath update the links in /dev/disk/by-label - So if I do a disk rescan on the host, all of those links are reset from the emcpower devices to the /dev/sdX devices... I have to reboot to add a disk, and be able to mount the emcpower device by label.
Am I missing something, or should I just stick with the native multipath setup?
dynamox
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February 14th, 2013 12:00
have you alos looked at "Host Connectivity guide for Linux" document ? We are booting from SAN ..and you are right there are some steps that you need to do to make it work correctly, they are all documented in these two documents. Let us know when you get stuck
AaronAnderson1
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February 15th, 2013 11:00
Getting a new RHEL 6.x install is easy, so far.
The PowerPath admin guide references this script over and over but I don't have it...
/etc/opt/emcpower/emcpbfs_linux
any ideas on where to get that?
SKT2
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1.3K Posts
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February 15th, 2013 12:00
It should be part of power path rpm and if you have the it installled and not seeing this file , just ignore it. I had the same question in the past once
AaronAnderson1
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February 18th, 2013 06:00
I found the file in the RPM. It looks like the file doesn't get copied/installed with the rpm installation...
Alex_Ye
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February 23rd, 2013 22:00
There is a primus that describes how to enable Powerpath boot from SAN for RHEL 6: emc287613
1. Make sure that only one Fibre Channel cable is plugged into the host.
2. Enable the BIOS on one HBA, disable it on all others.
3. Make sure only ONE LUN is presented to the host (this is IMPORTANT!!!).
4. Select LUN 0 in the BIOS on HBA 1 for boot.
5. Boot the host and install RHEL 6.2 (no options, straight installation).
6. Select Specialized Storage Devices (as this is a SAN).
7. Select /dev/sda - Make sure that it is an active disk, not a LUNZ device.
8. Allow installation to proceed normally. Reboot at end of installation (as normal).
9. Move /boot/initramfs-xxxxx.img to /boot/initramfs-xxxxx.orig.img, where xxxxx is the kernel version.
10. Install the PowerPath, license and run "/etc/init.d/PowerPath start". Check the PowerPath configuration. Run the powermt save command.
11. Edit /etc/fstab to mount boot from /dev/emcpowera1.
12. Remountd /boot.
13. Change LVM filter to [ "a/emcpower.*/", "r/sd.*/", "r/disk.*/" ].
14. Build a new initramfs with "dracut /boot/initramfs-PP-$(uname -r).img $(uname -r)".
15. Add initramfs-PP-xxxxxx.img to /boot/grub/menu.lst.
16. Add the rest of the LUNs to the configuration via array masking.
17. Plug in the second FC cable, scan in the LUNs, run powermt config, and make sure all paths are active.
18. Reboot.
If not installing boot-from-SAN, the best approach is to load the OS without the SAN cables configured (thus bypassing dm-multipath installation) or to bring down the host, disconnect the FC cables, reboot the host, disable multipath (by editing multipath.conf), install PowerPath, then reconnect the cables and reboot the host. EMC is working on improved documentation of this procedure.