System Administration
cancel
Showing results for 
Search instead for 
Did you mean: 

4MB extent VG limitations...

SOLVED
Go to solution
Dave Cast
Frequent Advisor

4MB extent VG limitations...

Does anyone know off the top of their head what the VG max size limit is with 4mb extents set?

I've searched and searched and for some reason cannot find it -

v/r
Dave
Today is different and tomorrow the same.
15 REPLIES
Pete Randall
Outstanding Contributor

Re: 4MB extent VG limitations...

Wouldn't it depend on max_pe??? According to the vgcreate man page, max_pe can be up to 65535, making total size 65536*4MB. I'll let you do the math.


Pete

Pete
Dave Cast
Frequent Advisor

Re: 4MB extent VG limitations...

Yeah - I started doing the math right after I posted this - I remember seeing a table online showing reccommended PE sizes -

I need a 4TB VG - according to my caculations - I'll need to set a 64MB PE size. Yikes.
Today is different and tomorrow the same.
Torsten.
Acclaimed Contributor

Re: 4MB extent VG limitations...

This also depends on the LVM version, version 1.0 or 2.x ...

Hope this helps!
Regards
Torsten.

__________________________________________________
There are only 10 types of people in the world -
those who understand binary, and those who don't.

__________________________________________________
No support by private messages. Please ask the forum!

If you feel this was helpful please click the KUDOS! thumb below!   
Dave Cast
Frequent Advisor

Re: 4MB extent VG limitations...

I see talk of a 2TB limit in HPUX - is this the case?
Today is different and tomorrow the same.
sangilak
Trusted Contributor

Re: 4MB extent VG limitations...

Hi,


Check the document below for details on the various limits for the different LVM versions 1.0, 2.x in HP-UX:
http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c01914836/c01914836.pdf

You can of course also check the limits on your system itself with the 'lvmadm' command:
# lvmadm -t


sangilak
sangilak
Trusted Contributor

Re: 4MB extent VG limitations...

Whoops, forgot to copy/paste the actual output:

# lvmadm -t
--- LVM Limits ---
VG Version 1.0
Max VG Size (Tbytes) 510 <<<<<<<
Max LV Size (Tbytes) 16
Max PV Size (Tbytes) 2
Max VGs 256
Max LVs 255
Max PVs 255
Max Mirrors 2
Max Stripes 255
Max Stripe Size (Kbytes) 32768
Max LXs per LV 65535
Max PXs per PV 65535
Max Extent Size (Mbytes) 256

VG Version 2.0
Max VG Size (Tbytes) 2048 <<<<<<<
Max LV Size (Tbytes) 256
Max PV Size (Tbytes) 16
Max VGs 512
Max LVs 511
Max PVs 511
Max Mirrors 5
Max Stripes 511
Max Stripe Size (Kbytes) 262144
Max LXs per LV 33554432
Max PXs per PV 16777216
Max Extent Size (Mbytes) 256

VG Version 2.1
Max VG Size (Tbytes) 2048 <<<<<<<
Max LV Size (Tbytes) 256
Max PV Size (Tbytes) 16
Max VGs 2048
Max LVs 2047
Max PVs 2048
Max Mirrors 5
Max Stripes 511
Max Stripe Size (Kbytes) 262144
Max LXs per LV 33554432
Max PXs per PV 16777216
Max Extent Size (Mbytes) 256
Norman_21
Honored Contributor

Re: 4MB extent VG limitations...

Dave,

On an existing VG that I have in a system, it appears that I can increase the file system to 7TB but that will require renumbering the PE which may not be recommended by HP. However, this is an existing VG but in your case, you'll be creating a new one. Just wanted to share to give you an idea.


# vgmodify -t vgwhatever

Current Volume Group settings:
Max LV 255
Max PV 16
Max PE per PV 4357
PE Size (Mbytes) 8
VGRA Size (Kbytes) 624
VGRA space (Kbytes) without PE renumbering 896
VGRA space (Kbytes) PE renumbering lower 8192

Volume Group optimized settings (no PEs renumbered):
max_pv(-p) max_pe(-e) Disk size (Mb)
1 65535 524281
2 53756 430049
3 35836 286689
4 26876 215009
5 21500 172001
6 17916 143329
7 15356 122849
8 13308 106465
9 11772 94177
10 10748 85985
11 9724 77793
12 8956 71649
13 8188 65505
14 7676 61409
15 7164 57313
16 6652 53217
17 6140 49121
18 5884 47073
19 5628 45025
20 5372 42977
21 5116 40929
22 4860 38881
23 4604 36833

# vgmodify -t -n vgwhatever

Current Volume Group settings:
Max LV 255
Max PV 16
Max PE per PV 4357
PE Size (Mbytes) 8
VGRA Size (Kbytes) 624
VGRA space (Kbytes) without PE renumbering 896
VGRA space (Kbytes) PE renumbering lower 8192

Volume Group optimized settings (PEs renumbered lower):
max_pv(-p) max_pe(-e) Disk size (Mb)
15 65535 524288
16 63228 505832
17 59388 475112
18 56060 448488
19 53244 425960
20 50428 403432
21 48124 385000
22 45820 366568
23 44028 352232
24 41980 335848
25 40444 323560
26 38908 311272
27 37372 298984
28 36092 288744
29 34812 278504
30 33532 268264
31 32508 260072
32 31484 251880
33 30460 243688
34 29692 237544

# echo 524288*15|bc
7864320
# echo 7864320/1024|bc
7680
"Attitudes are contagious, is yours worth catching"/ My first point was given by SEP on January 31, 2003
Dave Cast
Frequent Advisor

Re: 4MB extent VG limitations...

# vgdisplay /dev/lv_images
--- Volume groups ---
VG Name /dev/vg_whatever
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 0
Open LV 0
Max PV 16
Cur PV 1
Act PV 1
Max PE per PV 16383
VGDA 2
PE Size (Mbytes) 128
Total PE 16383
Alloc PE 0
Free PE 16383
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0
VG Version 1.0.0

So it seems I have 1.0.0 which doesn't seem like it supports VG's above 2TB.

Today is different and tomorrow the same.
chris huys_4
Honored Contributor

Re: 4MB extent VG limitations...

Hi Dave,

Install the latest LVM command and kernel cumulative patches on HP-UX 11.23, which will up the max size of a volumegroup/logical volume to 16TB.

Patch Name: PHKL_40918

Patch Description: s700_800 11.23 LVM Cumulative Patch

[..]

No (superseded patches contained enhancements)

PHKL_36745:

This patch provides the kernel component for
the LVM Striped/Mirror and 16TB logical volume features. The Striped/Mirror LV feature allows the creation and use of logical volumes that are simultaneously striped and mirrored.

The 16TB LV feature allows accessing data
past the 2TB offset in logical volumes
(formerly logical volumes larger than 2TB could be created but could not be accessed beyond the 2TB boundary). To use these features, they must be explicitly enabled by installing PHCO_36746 or a superseding patch, because using them results in volume groups that are incompatible with prior releases and systems without these features. See the
Other Dependencies section of this document for the details.

Greetz,
Chris
Bill Hassell
Honored Contributor
Solution

Re: 4MB extent VG limitations...

> So it seems I have 1.0.0 which doesn't seem like it supports VG's above 2TB.

Only 11.31 will allow version 2.x VGs. If you are running 11.31 (an older release), you can upgrade to the latest LVM package:

https://h20392.www2.hp.com/portal/swdepot/displayProductInfo.do?productNumber=BaseLVM

Attached is the LVM limits document which covers HP-UX 11.00 through 11.31.


Bill Hassell, sysadmin
Dave Cast
Frequent Advisor

Re: 4MB extent VG limitations...

Only one problem - this is 11.31 September of 2007 - not 11.23.

Are there patches for 11.31 September of 2007?
Today is different and tomorrow the same.
Dave Cast
Frequent Advisor

Re: 4MB extent VG limitations...

THAT WAS IT! What made you think to check the software portion of the HP website? I've been digging through the patch database on the HP website, and found some rather confusing patches related to LVM (more to do with clustering and striping etc.) - never thinking it would be under software -


THANKS
Today is different and tomorrow the same.
Dennis Handly
Acclaimed Contributor

Re: 4MB extent VG limitations...

>Are there patches for 11.31 September of 2007?

You probably have to upgrade, rather than patch.
Ismail Azad
Esteemed Contributor

Re: 4MB extent VG limitations...

Hi Dave,

Dave

>I see talk of a 2TB limit in HPUX - is this the case?
> So it seems I have 1.0.0 which doesn't seem like it supports VG's above 2TB.

I beleive you have got the entities of LVM confused or it should be a typo error. Apparently, there is a 2TB limit but that is for a PV and not_a_VG. So that would make it possible to have VGs upto 510TB on LVM v1 . Max PVs of 255 are possible making that 255*2TB=510TB. Well if a VG size limit were to be limited to 2TB, then why not use a whole disk approach!. :)

Or are you for some reason not considering the feature of disk spanning at partition level which would limit the size of that pool of space to let's say 2Tb where you have one P.V in that V.G...

Regards
Ismail Azad

Read, read and read... Then read again until you read "between the lines".....
chris huys_4
Honored Contributor

Re: 4MB extent VG limitations...

> Attached is the LVM limits document which
> covers HP-UX 11.00 through 11.31.

Attached. tss.. Learn to fish.

http://docs.hp.com/

Moved to BSC (http://www.hp.com/go/hpux-core-docs)

HP-UX 11i Volume Management (LVM/VxVM) Software

HP-UX LVM Supported Limits (September 2008)

http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02019992/c02019992.pdf

Greetz,
Chris