[CentOS] pvcreate limitations on big disks?

Alan McKay

alan.mckay at gmail.com
Wed May 23 19:24:44 UTC 2012


OK folks, I'm back at it again.  Instead of taking my J4400 ( 24 x 1T
disks) and making a big RAID60 out of it which Linux cannot make a
filesystem on, I'm created 4 x RAID6 which each are 3.64T

I then do :

sfdisk /dev/sd{b,c,d,e} <<EOF
,,8e
EOF

to make a big LVM partition on each one.

But then when I do :

pvcreate /dev/sd{b,c,d,e}1

and then

pvdisplay

It shows each one as only half its actual size.

But if I take the last one and wipe the partition table and just do
pvcreate on the entire disk, it works

pvcreate /dev/sde

And then if I take the results from that and use the size to force a
size on another PV I get it right too

pvcreate /dev/sdd1 --setphysicalvolumesize=3.64T

I'd use the entire disk expect that this seems dangerous to me because
you do "sfdisk -l" and the disk appears to have no partition table
which might entice someone to thing it is unused.
And I'm not sure whether it is safe to use setphysicalvolumesize.
Anyone know for sure?

What are my alternatives?


  "/dev/sdb1" is a new physical volume of "1.64 TB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb1
  VG Name
  PV Size               1.64 TB
  Allocatable           NO
  PE Size (KByte)       0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               7bzxpQ-Md1o-Z73g-YzLX-xxj7-nszh-LucEFW

  "/dev/sdc1" is a new physical volume of "1.64 TB"
  --- NEW Physical volume ---
  PV Name               /dev/sdc1
  VG Name
  PV Size               1.64 TB
  Allocatable           NO
  PE Size (KByte)       0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               tlpJ6A-LPs1-NFbl-h1AZ-5aBX-yOuO-phcwWD

  "/dev/sdd1" is a new physical volume of "3.64 TB"
  --- NEW Physical volume ---
  PV Name               /dev/sdd1
  VG Name
  PV Size               3.64 TB
  Allocatable           NO
  PE Size (KByte)       0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               ifwmQQ-AOvK-Ke6L-2gEy-aJgJ-bb8d-DaJJDD

  "/dev/sde" is a new physical volume of "3.64 TB"
  --- NEW Physical volume ---
  PV Name               /dev/sde
  VG Name
  PV Size               3.64 TB
  Allocatable           NO
  PE Size (KByte)       0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               VPptAS-CFul-Awe9-TI7E-W9jq-zVdx-1mJjDR

[root at solexa1 ~]#


-- 
“Don't eat anything you've ever seen advertised on TV”
         - Michael Pollan, author of "In Defense of Food"



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