I have two fresh new IBM servers with DS3524 storage. Each server has two Qlogic HBA adapters with FC ports.
I have configured raid arrays with host mappings on ds3524. Each server has one HBA connected to DS controller A and and another HBA to DS controller B for redundancy.
The goal is to install OEL 5.9 on each server with multipathing enabled.
I have successfully installed OEL5.9 on the each server (linux mpath) on the local drives and multipath drives are successfully mounted on their mountpoints.
At this point all is ok, multipath -ll shows me all my multipathed drives with two paths for each.
By default OEL has installed with UEK kernel, but I need rhel native kernel.
I have booted with rhel kernel, then have downloaded rdac-LINUX-09.03.0C05.0652-source.tar.gz from netapp and installed kernel module and new initrd image.
After boot with new initrd multipath -ll shows me only one path for each drive.
This is my first expirience with network storages and multipathing.
What I am doing wrong ?
What is the difference between kernel bundled and ibm/netapp rdac drivers?
If you mess around with manual builds, then you are pretty much on your own ito of support and getting things to work.
Questions. Why do you need the RHEL kernel? Why does the UEK kernel not suffice (with better and latest driver support)? Why did you manually build RDAC drivers? Why do you want to use RDAC drivers? If RDAC drivers need to be build, why do it on RHEL and not UEK?
Just FYI - most of our RAC servers are Fibre Channel based for accessing storage. We use the UEK (newer RACs) and RHEL kernels (older RACs), with multipath.
Nothing else. No 3rd party drivers.
As these are RAC clusters, we are using ASM as storage manager (also not running ASMlib kernel driver either).
Thus my questions above - trying to determine just why you need the kernel and drivers you are having problems with.
Thanks for your replies.
I've solved the problem. It was my mistake. dm-multipath and RDAC are doing the same thing. But I tried to run their together.
IBM recommends to use RDAC, but rdac drivers build has failed with UEK kernel.
As far as RHEL kernel is certified for EBS, we're going to it + rdac drivers.
We're dont using RAC, just simple installation - 2 servers for apps and db tiers and one storage with two raids, one for each node.