How to tell how much free disk space can be allocated?

[Gino Castoldi_2]

Hi,

System: L2000 HP-UX 11.0 SureStore E Disk Array
12H.

We have a SureStore E Disk Array with 6 - 18GB drives installed. The system has two LV groups,
vg00 is for the system disk and vg01 is for our apps. I would like to know a way to figure out how much free space can I allocate to VG=vg01 volume group? We are running VxFS (not the Online option) so I know we can allocate more disk space to VG=vg01, I would like to know how to go about it.

(10 points to any good answer).
Thank you Gino.

[Mark Mitchell · Accepted solution]

There are a few ways depending on what level you are starting at.
On the 12h there are 8 max luns that can be set up and going over 50% of the disk allocated to lunds moves the array from a mirror to a raid with less performance.
To start here load the ARMserver from this website and you can get a good look at the 12h through sam by highlighting the main controler listed under disks and hit the tools-more information tab at the top.
If space has already been added to vg00 and vg01 and you want to see what is free to allocate then do a vgdisplay on the vg in question. Most out of the box setups are 4 meg per extent so multiplying the listed PE size by the free PE will show how much space can be added to a new or existing logical volume.
Here is the info on the ARMserver patch
PHCO_23262

[Eric Ladner]

A new VG means another physical volume. Your terminology might be a little off here. Physical volumnes are grouped into volume groups, then logical volumes are created on the volume group.

To see if there is extra unallocated space on your disk array, you'd have to use a utility or monitor. You could create another physical volume that you can allocate to a new or existing volume group. (not familiar with the E disk array, sorry).

If there is extra space on the vg01 volume group that was not allocated to the logical volume on that drive, you can see the extra space by doing a 'vgdisplay vg01' and looking at the 'Free PE' entry. Multply that number by 4 and that's the number of meg free you can allocate to another logical volume in that volume group.

Once you add free space or have unallocated space there now, it becomes a simple matter of unmounting the file system, doing a lvextend, and extendfs then remounting (see the man pages for more details on lvextend and extendfs)

[Uday_S_Ankolekar]

Hi,
It depends how you want to design it.
Since you have 6*18 GB You can use 5*18GB as vg01. But If you want to have one mirror copy then you can design as
2*18 as primary and 2*18 as mirror. And remaining 1 18G can be mirrored to system Files on vg00. This way you will have redundancy.

Just a thought,,

[Josh_13]

i agree with Eric, your terminology is confusing.

things i would like to know to be able to answer better:

how many physical disks are there?
what is the capacity of each one?
what are the sizes of the logical volumes upon each physical disk?
which logical volume do you wnat to allocate space to? some cannot simply be extended.

[S.K. Chan]

If I understand you correctly ..
First check your disk array to find out how many LUNs are configured and how much space is left unallocated for LUN.
# arraydsp -i
==> shows array serial number
# arraydsp -a | more
==> show details of the disk array.
From the LUNs number you would then determine in ..
# ioscan -fnC disk
if all the LUNs are seen by the system or not. Pick up those device path and cross check those against your vg00 and vg01 to find out which device is not assinged to a VG yet.
Once you've determine that, you can extend vg01 ..
# vgextend vg01
Now your vg01 should have more space.

[harry d brown jr]

Gino,

arraydsp -a ARRAYID

live free or die
harry

[Gino Castoldi_2]

Hi Everyone,

Thank you for your replies. (I'll be assigning
the ten points after this message).

Here is our setup as far as I can determine.
(We didn't set it up ourselves).
I looked at the Disk Array itself and I found the AutoRAID Capacity Planning Tool 1.0 website for some information.

Controller A:
One 18GB drive for each "slot".
Slots numbers 6, 5, and 4.

Controller B:
Same as Controller A.

All of these disks (as far as I can tell) are
in one Volume Group (/dev/vg01).
# vgdisplay vg01
--- Volume groups ---
VG Name /dev/vg01
VG Write Access read/write
VG Status available, exclusive
Max LV 255
Cur LV 3
Open LV 3
Max PV 16
Cur PV 2
Act PV 2
Max PE per PV 4097
VGDA 4
PE Size (Mbytes) 4
Total PE 8190
Alloc PE 1250
Free PE 6940
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

There are three logical volumes under this VG.
--------------------------------------------
--- Logical volumes ---
LV Name /dev/vg01/lvu01
LV Status available/syncd
LV Size (Mbytes) 3000
Current LE 750
Allocated PE 750
Used PV 1

LV Name /dev/vg01/lvolOV1
LV Status available/syncd
LV Size (Mbytes) 1000
Current LE 250
Allocated PE 250
Used PV 1

LV Name /dev/vg01/lvolOV2
LV Status available/syncd
LV Size (Mbytes) 1000
Current LE 250
Allocated PE 250
Used PV 1

Hopefully this extra info will help.
If you need more info just let me know.

Thank you Gino.

[Gino Castoldi_2]

Hi everyone,

I forgot to include this info:

--- Physical volumes ---
PV Name /dev/dsk/c4t5d0
PV Name /dev/dsk/c5t4d0 Alternate Link
PV Status available
Total PE 4095
Free PE 3345

PV Name /dev/dsk/c4t5d1
PV Name /dev/dsk/c5t4d1 Alternate Link
PV Status available
Total PE 4095
Free PE 3595

Thank you Gino.
(Ten points to any good answer).

[S.K. Chan]

Need this output ..

# strings /etc/lvmtab
# ioscan -fnC disk
# arraydsp -a