How to increase VG size that exists on SAN (STK D280)

[M Bilal]

Hi,
I am using HP-UX 11iv1 Release B.11.11, I have a Volume Group that physically exists on the SAN (StorageTek D280), I have increased the size of this VG on SAN but on my HP-UX machine I still see the same old size of that VG.
My question is that how can I increase the VG size on my HP-UX whose size is already increased on SAN.

--
Muhammad Bilal

[Duncan Edmonstone · Accepted solution]

well the "VG" doesn't exist on the SAN does it (by which I mean the STK cas no "concept" or knowledge of the VG) - only the LUNs do - so what did you do to those LUNs? Did you resize them? That's a bad idea as LVM in 11.11 can't deal with an underlying disk size change - better to just add more LUNs and extend the volume group on the host...

A very similar question came up recently - see this thread here:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1335775

HTH

Duncan

[Pete Randall]

http://forums13.itrc.hp.com/service/forums/questionanswer.do?threadId=1335775


Pete

[Emil Velez]

YOu increase the size of a volume group by adding additional physical volumes to the volume group.

If you extend the LUN itself you may not be able to use the space except with 11.23 and 11.31 with the vgmodify command.

I am pretty sure 11.11 does not support dynamic lun expansion.

[M Bilal]

Hi Duncan

I am managing StorageTek-D280 SAN through SANtricity Storage Manager utility. On my SANtricity Storage Manager I have volume group named "Volume Group 5" in which I have volume "Ora1" I have increased the size of "Ora1" from 20Gb to 30 Gb. Thats good increased with no errors, but when I checked on my HP-UX the mapped volume "Ora1" was 20 Gb. Kindly suggest me what to do.
1). How to get 30Gb logical volume on my HP-UX, keeping in mind I can't backup,remove,create and restore new logical volume due to some policy constraints.

2). If I create a new volume on my SAN, what will be the procedure to extend my existing logical volume into new volume in HP-UX.

3). If I got LUN of new volume from SAN how to work with LUN in HP-UX and add it into my existing Logical Volume.
...
Bilal

[Duncan Edmonstone]

Muhammad,

The volume group on the STK device is not releated in any way to the volume group you see on the HP-UX host, except in your head and at some abstract level in terms of grouping LUNs together.

You will need to reset the LUN you increased in size back to the size it was previous to the change. I hope you know *exactly* what size it was previously, as if you make it too small, you risk corrupting the data you have on the LUN. If you're not sure, best probably to just leave it for the moment - you just won't have access to that extra 10GB of space...

So to get extra space in your volumes on HP-UX, do the following:

First identify which volume group the volume is in by running "bdf" on the host and looking at the volume nae associated with the filesystem - should be something like /dev/vgNN/lvolX - where vgNN is the volume group name, and lvolX is the logical volume name

i) Create a new KLUN in the group you hgave defined on the STYK device of 10GB in size, and present this LUN to the HP-UX host (I can't give you more details on this as I don't know the SANtricity tool)

ii) run the commands:

ioscan
insf -C disk

If you've presented the LUN correctly, that should show you the new disk device that has been created (the output of insf should tell you that)

iii) extend the disk into the volume group:

pvcreate /dev/rdsk/cXtYdZ
vgextend vgNN /dev/dsk

if there is more than one "path" to your LUN, you should include the other patsh as well when you vgextend

iv) once the new is in the volume group, check how much additional space you have in the volume group using vgdisplay:

vgdisplay vgNN

you should see a number of "Free PE" which indicates the number of free physical extents in the VG - multiply this by the value of "PE Size (MBytes)" and it should come to around the 10GB you have added

now extend the logical volume you want to grow by running lvextend using the value from "Free PE" as N below to add all these free extents to your logical volume:

lvextend -l N /dev/vgNN/lvolX

v) Now you need to grop the filesystem into the new space in the LV - how you do this depends on whether you have OnlineJFS installed - if you do you can do it online, if you don't you'll need to stop all IO to the filesystem (probably by stopping your application) anmd unmount it while you extend the filesystem. Check if you have OnlineJFS using "swlist | grep -i jfs"

HTH

Duncan

[Duncan Edmonstone]

Bilal,

Are you the admin for this system? If you're not clear on how to do basic tasks like this, you need to speak to your boss about some training.

Without going on a rant, there are far too many individuals working on IT systems these days with no training and no experience of what they are doing - if it wasn't for forums like this, and google there would be a lot of systems down for a lot of the time.

HTH

Duncan

[M Bilal]

I have created new LUN and extended my VG by using that LUN. Thanks to Duncan for his support and guidance.