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February 1st, 2011 13:00
Boot from SAN for Symmetrix/AIX6.
I'm looking for step by step procedures for booting IBM Pseries AIX 6 from SAN (DMX4 using MDS 9506 switches). I'm starting to believe that no such procedures exist. The "EMC Host Connectivity Guide for IBM Aix" is a great document. It even has a section titled "Creating a Fibre Channel boot device on an EMC array". This section shows examples of how to migrate an existing Symmetrix SAN BOOT volume to another volume using TimeFinder (what if we don't own TimeFinder). It never tells how to set up the original SAN Boot volume.
EMC has a great tool called the Symmetrix DMX Procedure Generator. It gives very detailed steps for many different config options - problem is it does not address Boot from SAN.
I opened a case this morning with EMC. The guy had no idea how to boot from disk with DMX4 and AIX6. He has re-assigned the case to someone else but no call back yet.
As I search PowerLink and the Internet - I see lots of references to Boot from Disk with Symm/AIX6 but know one really knows how to do it. I have talked to other customers and I always get the same answer - oh yeah it can be done - we did it at my last company. I say "great can you give me the steps". The reply is something like - I really did not set it up, my colleague did. I say fine, can I talk to him. The reply is something like no he died and no one else knows how to make it work.
There is tons of advice on making sure you have the latest drivers, most current PowerPath and ODM drivers etc. But I still can not find any procedures? Can someone point me to the procedures?
subash159
2 Posts
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March 10th, 2011 00:00
Same boat as Brad...and still searching for the AIX-SAN boot-EMC procedures.
AARoberts
2 Posts
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March 10th, 2011 11:00
Hello,
First off let's get the bad news out of the way... there is no step by step procedure written down anywhere.
The good news? I do it all the time in the lab and I'll tell you how I set up boot from SAN here.
As with any AIX system there are multiple ways to do this. This is how I like to set it up.
You may think I'm a heathen or a simpleton or maybe both, but I prefer smitty for some tasks. So if you want the line commands you can hit F6 from any menu I mention to get them.
My assumption is you are going to be doing this with powerpath.
The alt_disk_clone Method
1) pick a disk for your new boot from san rootvg. Obviously it needs to be big enough to house the rootvg. Since your backend SAN disk has already got some kind of raid protection on it you're probably only going to want to use one disk. If that is the case I suggest you skinny your rootvg down to 1 disk prior to cloning it. If you don't want to do that use two SAN disks and skinny that rootvg down to one after you've cloned it.
2) Enter smitty install
select "Alternate Disk Installation"
3) select "Clone the rootvg to an Alternate Disk"
4) Enter your target SAN disk in "Target Disk(s) to install"
You can enter a powerpath device here and it will work. smitty will tell you it failed at the end because when it goes to update the bootlist it's not going to be able to since bootlist only allows hdisk entries and not hdiskpower entries. That's not an issue and we'll see why later. If you don't like that you can do as in the following example:
powermt display dev=hdiskpower0
Pseudo name=hdiskpower0
Symmetrix ID=000192604026
Logical device ID=00FC
state=alive; policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
---------------- Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
1 fscsi1 hdisk150 FA 7gA active alive 0 0
0 fscsi0 hdisk37 FA 10gA active alive 0 0
powermt remove dev= hdiskpower0
rmdev -dl hdisk37
This will skinny us down to just 1 path and one hdisk. You can now use this as your Target Disk(s) to install. If you have more paths you need to get rid of all of them until you only have 1.
5) There is an option on the Clone menu to "ACCEPT new license agreements?". I always set it to yes.
6) Hit enter and let it start building the clone of your rootvg on an alternate disk. If you didn't pick a disk with enough space it will fail here.
7) If we list out the vg’s we see we have a new vg called altinst_rootvg who lives on the target disk you selected. If this is a hdiskpower device we display the underlying hdisks with a
powermt display dev=hdiskpowerN
We take all of those hdisks and put them in the bootlist with:
bootlist -m normal hdiskn hdiskn hdiskn hdiskn
Now it is time to reboot with: shutdown -Fr
8) When we come back up we see we have an old_rootvg and a new rootvg which is booted off SAN. Your hdisk number will probably change to something different. Now let’s setup for powerpath control of the rootvg (this gives us load balancing and failover protection).
9) To enable powerpath on rootvg you enter:
pprootdev on
You are now good to go after a reboot. Before you reboot make sure your bootlist is correct by doing a:
bootlist -m normal -o
This will display all of the boot devices. Make sure all of the new rootvg hdisks are in there.
10) reboot.
11) When you come up you should see the new rootvg on the power devices.
Now that you're on power devices you need to remember that prior to doing a mksysb, or anything that calls a bosboot or bootlist you need to run the command:
pprootdev fix
This will move the pvids, vgids, and so on from the hdiskpower device to the hdisks so those commands will work properly. We have a lot of customers that that just put pprootdev fix in their startup scripts so they don't have to worry about it. Running pprootdev fix does NOT turn off load balancing or failover protection for the rootvg.
BONUS!
Your old rootvg is right where you left it so if you want to back something of or keep it around as insurance you can do that!
I hope that helps!
subash159
2 Posts
0
March 10th, 2011 21:00
Thanks Roberts for the detailed steps,
Some points on how I implemented :-
EMC.Symmetrix.aix.rte 5.3.0.4 COMMITTED EMC Symmetrix AIX Support
EMC.Symmetrix.fcp.MPIO.rte 5.3.0.4 COMMITTED EMC Symmetrix FCP MPIO Support
EMC.Symmetrix.iscsi.rte 5.3.0.4 COMMITTED EMC Symmetrix iSCSI Support
8 paths
Enabled hdisk2 fscsi0
Enabled hdisk2 fscsi1
Enabled hdisk2 fscsi2
Enabled hdisk2 fscsi3
Enabled hdisk2 fscsi4
Enabled hdisk2 fscsi5
Enabled hdisk2 fscsi6
Enabled hdisk2 fscsi7
5) Then I just added this into rootvg and mirrored...and later unmirrored and reducevg the Virtual disk.
Now system is running and booting fine with SAN disk...we didnt plan for a mirror of rootvg with another SAN Lun,as we felt we have enough paths for redundancy.
All said....I was looking at a "Best Practice" kind of procedure specifically for these kind of setups.