I'm completely new to linux admin and file system. Recently we acquired an HP MSA P2000 san. I've setup the disk into a vdisk and created 3 volumes on it. On Centos 7, I've also setup the multipath mapper and have those volumes mapped into /dev/mapper/mpatha, mpathb and mpathc.
I saw on a couple of web site that they do the following: (whichever is the underlying disk of e.g. mpatha)
# fdisk /dev/sdd # kpartx -a /dev/mapper/mpatha # mkfs.ext3 /dev/mapper/mpathap1
to format the disk. Redhat DM multipath document recommend
# pvcreate /dev/mapper/mpatha
to create an LVM volume.
My question is
1. For the former, when the volume is expanded later, do I need to backup and fdisk, mkfs the entire /dev/sdd again?
Then when you expand your disk, you do a fdisk to create a new partition and you do a>
pvcreate /dev/mapper/mpatha2 vgextend VOLGROUPNAME /dev/mapper/mpatha2
2.For the latter, it seems like vdisk and volume creation is already managed by the HP P2000 disk management tool, it seems I don't really need to further create partitions/volumes on top of it. Should I probably not LVM here, no?
Believe me, you want to. Managing disk spaces with pvs vgs and lvms is really neat and easy
3.What's the right thing to do? do I really need to 'format' and initialize a further partition?
pvcreate /dev/bla vgcreate vgname /dev/bla lvcreate -n lv_name -L 1G vgname mkfs.ext4 /dev/mapper/<vgname>-<lvname>
When you want to get more space:
lvextend -L +1G /dev/mapper/<vgname>-<lvname> resize2fs /dev/mapper/<vgname>-<lvname>
pvresize /dev/mapper/mpathato re-detect volume size and then automatically expand. — Apr 04, 2017 at 00:41