topic Re: max vg's in Operating System - HP-UX

max vg's

Nobody's Hero — Tue, 17 Dec 2002 14:16:45 GMT

Is it safe to say that I can increase the 'maxvgs' from 10 to lets say 16? Without creating any problems?

Re: max vg's

Nobody's Hero — Tue, 17 Dec 2002 14:18:47 GMT

actually I have vg0-6 created. I need to create 7-14, but then I will remove 1-6. Does this create a problem? do the vg numbers need to be in order or can I have '0' and 7-14.

Re: max vg's

Patrick Wallek — Tue, 17 Dec 2002 14:19:49 GMT

Yes, that kernel parameter should not cause you any problems. Just remember that you will have to reboot the machine in order for it to take effect.

Re: max vg's

T G Manikandan — Tue, 17 Dec 2002 14:21:22 GMT

Yes,by default the value is 10.
If you are to create 14 groups then you need to definitely increase maxvgs.

there is no problem in increasing that.

change the kernel parameter,build a new kernel.

Thanks

Re: max vg's

Pete Randall — Tue, 17 Dec 2002 14:21:55 GMT

Robert,

You can safely increase maxvgs and you can also name your vg's whatever you want.

Pete

Re: max vg's

John Poff — Tue, 17 Dec 2002 14:39:10 GMT

Hi,

One thing to keep in mind is that your minor device numbers for your group files are in hexadecimal, and the 'maxvgs' parameter sets what the maximum value of your minor number can be. Don't make the mistake I made once when I had a box with 'maxvgs' set to 80. I thought I couldn't create any more VGs, even though I had way less than 80 VGs on the box, because my vgcreate kept choking. It turns out that we hadn't used all the possible hex values for the minor numbers [ie. 1a, 1b,...,1f, 2a, 2b,... etc.]. So if you set your maxvgs for 16, your minor numbers will go from 00-09 and then 0a-0f and finally 10.

JP

Re: max vg's

Simon Hargrave — Tue, 17 Dec 2002 14:47:40 GMT

Remember also that the minor number doesn't have to tie in with your vg number (though it does make it easier to manage if it does).

You could, for example, have the following: -

VG Minor
vg00 0x000000
vg01 0x010000
vg10 0x020000
vg11 0x030000

etc...so long as the minor numbers are unique. This way you can have a volume group called vg20, but still have maxvgs set low.