About "hpux -lq"

 
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arkie
Super Advisor

About "hpux -lq"

Can someone pls appraise me about the use of "-lq" option to boot with hpux.

About the differences between using only "hpux" and "hpux -lq", when say, my alternate root disk goes bad , and i am booting with only my primary disk. Which option should i go for?

Thanks in advance.
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Pete Randall
Outstanding Contributor
Solution

Re: About "hpux -lq"

Normally booting requires a quorum: both your root disks must be present in order to boot successfully. If you have a third mirrored boot volume, then you could still have a quorum even when one failed, but, in normal, two copy situations, one failed disk will prevent boot from happening. Therefore, the recommended practice is to replace your normal "hpux" boot string with "hpux -lq", which will ignore the quorum requirement when one of the disks fails.

Use "hpux -lq" in a mirrored environment.


Pete

Pete
arkie
Super Advisor

Re: About "hpux -lq"

Hi Pete, thanks for your response.

Suppose the primary disk is OK and the alternate disk has gone faulty. In that situation, as have seen in 9000 systems - the processor does boot from the first available device automatically.

In that situation, and in another, where we interrupt and go with the "hpux -lq" option from ISL, is there any major difference in the environment? Are there any extra processes that get forked when the system keeps looking for the second disk (when not using the -lq option). I remember hearing that kind of a situation someone faced with a SD32 vpar, where lots of like processes (can grep with "evmshow") come alive and eat away the resources. The system becomes very slow and irresponsive. One can start killing the processes, but they keep on coming.
Pete Randall
Outstanding Contributor

Re: About "hpux -lq"

I've honestly never heard of such a thing, but who knows? I would think that, at that point, you would be happy just to have a system, slow or not.


Pete

Pete
arkie
Super Advisor

Re: About "hpux -lq"

Yes Pete. That's right.

Just want to ask - is there any significant performance change between booting hpux using -lq and not using -lq, when one disk is out (in the 2-copy scenario) ?

Sorry for repeating, just want to be clear on that.
Pete Randall
Outstanding Contributor

Re: About "hpux -lq"

There shouldn't be any measureable performance difference. There could be a very slight difference in I/O: writes would only have to happen once (good), reads would only have one source (bad). Overall, however, you shouldn't be able to notice any performance difference.


Pete

Pete
Matti_Kurkela
Honored Contributor

Re: About "hpux -lq"

> Suppose the primary disk is OK and the alternate disk has gone faulty. In that situation, as have seen in 9000 systems - the processor does boot from the first available device automatically.

Yes, the bootloader will successfully load the kernel - but if vg00 is mirrored with MirrorDisk and "-lq" is not specified, as soon as the kernel tries to activate the vg00 volume group for mounting the root filesystem, the kernel will panic if the alternate half of the mirrored system disk is not available.

This is because the standard quorum requirement prevents it from activating vg00 and thus from mounting the root filesystem. Without the root filesystem, the boot cannot complete.


The effect of "hpux -lq" vs. "hpux" for vg00 is similar to "vgchange -a y -q n" vs. "vgchange -a y" when mounting a data volume group that contains failed mirrors: it allows the VG to be activated even if the mirror is not whole. It has no other effects.

If you're not using MirrorDisk, then the "-lq" option is not necessary for you.

For example, if your vg00 is on a single disk and your alternate boot disk is a DRD clone of the primary boot disk, there is no need to use "-lq".

MK
MK
Benoy Daniel
Trusted Contributor

Re: About "hpux -lq"

If your boot disk is mirrored and one of the disk fails, you cant get the system booted without -lq option.

Re: About "hpux -lq"

this is to disable lvm quorum ib hpux.for two disks the quorum insists that 51% of disks should be present.
The quorum is introduced as HP wants to insure if you have atleast a mirror disk.
This quorum checking is removed using hpux -lq.