LinuxQuestions.org - Query about the LVM?

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Query about the LVM?

My Fedora 11 hard disk space setup is

Code:

[root@localhost ~]# fdisk -l



Disk /dev/sda: 250.0 GB, 250059350016 bytes

255 heads, 63 sectors/track, 30401 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk identifier: 0x00000001



  Device Boot      Start        End      Blocks  Id  System

/dev/sda1              1        1275    10241406    7  HPFS/NTFS

/dev/sda2            1276      30401  233954595    f  W95 Ext'd (LBA)

/dev/sda5            1276        5099    30716248+  7  HPFS/NTFS

/dev/sda6            5100      11473    51199123+  7  HPFS/NTFS

/dev/sda7          11474      17847    51199123+  7  HPFS/NTFS

/dev/sda8  *      17848      17873      204799+  83  Linux

/dev/sda9          17873      30401  100635204  8e  Linux LVM



Disk /dev/dm-0: 98.8 GB, 98838773760 bytes

255 heads, 63 sectors/track, 12016 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk identifier: 0x00000000



Disk /dev/dm-0 doesn't contain a valid partition table



Disk /dev/dm-1: 4211 MB, 4211081216 bytes

255 heads, 63 sectors/track, 511 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk identifier: 0x00000000



Disk /dev/dm-1 doesn't contain a valid partition table

[root@localhost ~]#

Code:

root@localhost ~]# pvdisplay

  --- Physical volume ---

  PV Name              /dev/sda9

  VG Name              VolGroup

  PV Size              95.97 GB / not usable 580.00 KB

  Allocatable          yes (but full)

  PE Size (KByte)      4096

  Total PE              24569

  Free PE              0

  Allocated PE          24569

  PV UUID              qLL0E0-dSrG-Uw2P-Q3Hi-yMUx-3qtv-VUZQAf

  

[root@localhost ~]# ^C

[root@localhost ~]#

Code:

[root@localhost ~]# vgdisplay

  --- Volume group ---

  VG Name              VolGroup

  System ID            

  Format                lvm2

  Metadata Areas        1

  Metadata Sequence No  3

  VG Access            read/write

  VG Status            resizable

  MAX LV                0

  Cur LV                2

  Open LV              2

  Max PV                0

  Cur PV                1

  Act PV                1

  VG Size              95.97 GB

  PE Size              4.00 MB

  Total PE              24569

  Alloc PE / Size      24569 / 95.97 GB

  Free  PE / Size      0 / 0  

  VG UUID              MxbEko-QoTK-ObyY-cwF1-8Fzf-cvat-SwNccQ

  

[root@localhost ~]#

Code:

[root@localhost ~]# lvdisplay

  --- Logical volume ---

  LV Name                /dev/VolGroup/lv_root

  VG Name                VolGroup

  LV UUID                LSScW6-oe33-fvR0-4hhM-MFHb-Pjv2-ewkeFX

  LV Write Access        read/write

  LV Status              available

  # open                1

  LV Size                92.05 GB

  Current LE            23565

  Segments              1

  Allocation            inherit

  Read ahead sectors    auto

  - currently set to    256

  Block device          253:0

  

  --- Logical volume ---

  LV Name                /dev/VolGroup/lv_swap

  VG Name                VolGroup

  LV UUID                3SUYIk-9juP-ARsq-RATf-f6PO-Us45-15f5pU

  LV Write Access        read/write

  LV Status              available

  # open                1

  LV Size                3.92 GB

  Current LE            1004

  Segments              1

  Allocation            inherit

  Read ahead sectors    auto

  - currently set to    256

  Block device          253:1

  

[root@localhost ~]#

The Linux was installed through automatic partition option.

Few doubts to ask:
1. What partitions are recommended to be created on LVM?
Is boot and swap partition recommended?

2.What more partition I can create with this LVM?

These days you can put what you like on LVM.
Used to be you couldn't put /boot on it.
Read up about it to make sure you want what it does.
It's often used like RAID - only more flexible.

Any specific reason for not putting /boot.
As I think if it put could save our life more.

Quote:

Originally Posted by Simon Bridge (Post 3877754)

These days you can put what you like on LVM.
Used to be you couldn't put /boot on it.

You still can't if you use luks encrypted PVs, but that's a special case.

Simon is correct: create whatever lv's you feel like. Partitioning is a very personal choice.

Here's mine. I'm sure you can guess where they're mounted based on the lv names. :)

Code:

root@nix:~# pvs

  PV                VG    Fmt  Attr PSize  PFree  

  /dev/mapper/pvsda5 rootvg lvm2 a-  306.41G 184.91G

root@nix:~# lvs

  LV      VG    Attr  LSize  Origin Snap%  Move Log Copy%  Convert

  lvhome  rootvg -wi-ao  8.00G                                      

  lvlocal rootvg -wi-ao  80.00G                                      

  lvopt  rootvg -wi-ao 512.00M                                      

  lvroot  rootvg -wi-ao 512.00M                                      

  lvtmp  rootvg -wi-ao 512.00M                                      

  lvusr  rootvg -wi-ao  16.00G                                      

  lvvar  rootvg -wi-ao  16.00G                                      

root@nix:~#

I have enough free ram not to need swap, but should I ever need it, I'll add a lvswap to the collection.

P.S. Some people prefer to keep / (rootfs) and /boot outside of lvm to help with resilience and to ensure that you can still boot the system to a maintenance shell if your lvm config gets corrupted somehow. Personally, I don't subscribe to this and I keep a live-cd to hand to boot from should I ever end up in that situation.

/boot is where the kernel lives... and the kernel contains the drivers which can manage the lvm volume. Thus, it used to be a bit like opening a box with the key locked inside it. These days, the ability has been added to grub.

If you use encryption, you still have the issue that something must be unencrypted to load the keys. ince /boot is not writable in normal operation, it is safe to leave unencrypted. Unlike windows which can write sensitive data anywhere and so needs whole-disk encryption.

It is not too uncommon in linux to put /boot on a keydrive though - so it will only boot with the key in the lock as it were. The internal drive can be totally encrypted then.

Note on swap: if you want to use hibernate - you need swap.
If you have lots of RAM, you can get away with lowering swappiness.