[linux-lvm] understanding large LVM volumes
Randall A. Jones
rajones at svs.gsfc.nasa.gov
Fri Jan 14 17:38:10 UTC 2005
I am trying to understand what the size limitations of VGs are for LVM2.
I am running 2.6.10-1.741_FC3smp, lvm2-2.00.25
The HOWTO document has really helped my understanding of the general
My goal is to create a 4+TB VG with current devices and then be able to
expand this VG to 10+TB when new resources become available.
My questions are as follows.
What is the maximum size of a single VG?
How does the Physical Extent size affect the maximum VG size?
How does one go about chosing a PE size for a VG?
Does anyone have experience with very large LVM VGs?
I want to ensure that I choose a good PE size when creating this large
VG and that
I don't paint myself into a corner, making it difficult to grow to 10TB
when the time
Any information, suggestions, or experiences for/with large volumes would
be much appreciated.
As a test, I created a VG with 3 devices totaling 4.3TB. I used only
[root at damascus ~]# pvscan
PV /dev/sdc1 VG testvg lvm2 [431.99 GB / 0 free]
PV /dev/sdd1 VG testvg lvm2 [1.95 TB / 0 free]
PV /dev/sde1 VG testvg lvm2 [1.95 TB / 0 free]
Total: 3 [4.33 TB] / in use: 3 [4.33 TB] / in no VG: 0 [0 ]
[root at damascus ~]# vgdisplay
--- Volume group ---
VG Name testvg
Metadata Areas 3
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 3
Act PV 3
VG Size 4.33 TB
PE Size 4.00 MB
Total PE 1134586
Alloc PE / Size 1134586 / 4.33 TB
Free PE / Size 0 / 0
VG UUID hnKF8h-Infa-wKiE-KtUT-OByG-q0pe-Nd4taB
Randall Jones GST NASA Goddard Space Flight Center
HPC Visualization Support http://hpcvis.gsfc.nasa.gov
Scientific Visualization Studio http://svs.gsfc.nasa.gov
rajones at svs.gsfc.nasa.gov Code 610.3 301-286-2239
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