Creation of a partion for an unallocated area
For executing it, have to follow this nice tutorial - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/storage_administration_guide/#s2-disk-storage-parted-create-part
either fron the beginning of OS_setup it's possible to divide storage to proper parts
by creating logical volumes for cache
| lv_cache 12G | lv_cache_meta 24M |
or later, after running newly deployed server
- lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 252:0 0 50G 0 disk
├─vda1 252:1 0 953M 0 part /boot
└─vda2 252:2 0 45.7G 0 part
├─centos7-root 253:0 0 30.8G 0 lvm /
├─centos7-swap 253:1 0 2.8G 0 lvm [SWAP]
├─centos7-home 253:2 0 956M 0 lvm /home
├─centos7-lv_cache 253:3 0 11.2G 0 lvm /cache/lv_cache
└─centos7-lv_cache_meta 253:4 0 24M 0 lvm /cache/lv_cache_meta
- lvconvert --type cache-pool --cachemode writethrough --poolmetadata centos7/lv_cache_meta centos7/lv_cache
WARNING: Converting logical volume centos7/lv_cache and centos7/lv_cache_meta to cache pool's data and metadata volumes with metadata wiping.
THIS WILL DESTROY CONTENT OF LOGICAL VOLUME (filesystem etc.)
Do you really want to convert centos7/lv_cache and centos7/lv_cache_meta? [y/n]: y
Logical volume centos7/lv_cache_meta contains a filesystem in use.
Aborting. Failed to deactivate centos7/lv_cache_meta.
- umount /cache/lv_cache_meta
- umount /cache/lv_cache
- lvconvert --type cache-pool --cachemode writethrough --poolmetadata centos7/lv_cache_meta centos7/lv_cache
WARNING: Converting logical volume centos7/lv_cache and centos7/lv_cache_meta to cache pool's data and metadata volumes with metadata wiping.
THIS WILL DESTROY CONTENT OF LOGICAL VOLUME (filesystem etc.)
Do you really want to convert centos7/lv_cache and centos7/lv_cache_meta? [y/n]: y
Volume group "centos7" has insufficient free space (2 extents): 6 required. - pvs
PV VG Fmt Attr PSize PFree
/dev/vda2 centos7 lvm2 a-- 45.67g 8.00m - lvreduce -L 11G /dev/centos7/lv_cache
Size of logical volume centos7/lv_cache changed from 11.18 GiB (2861 extents) to 11.00 GiB (2816 extents).
Logical volume centos7/lv_cache successfully resized. - lvconvert --type cache-pool --cachemode writethrough --poolmetadata centos7/lv_cache_meta centos7/lv_cache
WARNING: Converting logical volume centos7/lv_cache and centos7/lv_cache_meta to cache pool's data and metadata volumes with metadata wiping.
THIS WILL DESTROY CONTENT OF LOGICAL VOLUME (filesystem etc.)
Do you really want to convert centos7/lv_cache and centos7/lv_cache_meta? [y/n]: y
Converted centos7/lv_cache to cache pool. - lvs -a -o +devices
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert Devices
home centos7 -wi-ao---- 956.00m /dev/vda2(0)
lv_cache centos7 Cwi---C--- 11.00g lv_cache_cdata(0)
[lv_cache_cdata] centos7 Cwi------- 11.00g /dev/vda2(955)
[lv_cache_cmeta] centos7 ewi------- 24.00m /dev/vda2(3816)
[lvol0_pmspare] centos7 ewi------- 24.00m /dev/vda2(3771)
root centos7 -wi-ao---- 30.73g /dev/vda2(3822)
swap centos7 -wi-ao---- 2.80g /dev/vda2(239) - lvconvert --type cache --cachepool centos7/lv_cache centos7/root
Do you want wipe existing metadata of cache pool volume centos7/lv_cache? [y/n]: y
Logical volume centos7/root is now cached. - lvs -a -o +devices
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert Devices
home centos7 -wi-ao---- 956.00m /dev/vda2(0)
[lv_cache] centos7 Cwi---C--- 11.00g 0.00 5.91 0.00 lv_cache_cdata(0)
[lv_cache_cdata] centos7 Cwi-ao---- 11.00g /dev/vda2(955)
[lv_cache_cmeta] centos7 ewi-ao---- 24.00m /dev/vda2(3816)
[lvol0_pmspare] centos7 ewi------- 24.00m /dev/vda2(3771)
root centos7 Cwi-aoC--- 30.73g [lv_cache] [root_corig] 0.00 5.91 0.00 root_corig(0)
[root_corig] centos7 owi-aoC--- 30.73g /dev/vda2(3822)
swap centos7 -wi-ao---- 2.80g /dev/vda2(239) - lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 252:0 0 50G 0 disk
├─vda1 252:1 0 953M 0 part /boot
└─vda2 252:2 0 45.7G 0 part
├─centos7-swap 253:1 0 2.8G 0 lvm [SWAP]
├─centos7-home 253:2 0 956M 0 lvm /home
├─centos7-lv_cache_cdata 253:3 0 11G 0 lvm
│ └─centos7-root 253:0 0 30.8G 0 lvm /
├─centos7-lv_cache_cmeta 253:4 0 24M 0 lvm
│ └─centos7-root 253:0 0 30.8G 0 lvm /
└─centos7-root_corig 253:5 0 30.8G 0 lvm
└─centos7-root 253:0 0 30.8G 0 lvm /Rebuild initramfs
nano /etc/fstab
#/dev/mapper/centos7-lv_cache /cache/lv_cache ext4 defaults 1 2
#/dev/mapper/centos7-lv_cache_meta /cache/lv_cache_meta ext4 defaults 1 2
# dracut -v -f
This will rebuild the initramfs to include the cache LV.
use the dracut -f command to rebuild the initial ramdisk ( initrd ), and reboot the system for the changes to take effect.
https://wiki.centos.org/TipsAndTricks/CreateNewInitrd
dracut --regenerate-all -f && grub2-mkconfig -o /boot/grub2/grub.cfg
Creating a New Initial RAM Disk
If you have changed a motherboard or moved a disk to a different system it may fail to boot due to the lack of appropriate drivers in the initial RAM disk image (initramfs for CentOS 6).
Boot in Rescue Mode
- Boot from a CentOS installation disc (for example, CD #1 or DVD).
Type "linux rescue" at the "boot:" prompt.
- Mount all filesystems in read-write mode.
Create the New Initramfs or Initrd
Change root to real root ('/') on your hard disk and make the new initramfs or initrd.
mount --bind /proc /mnt/sysimage/proc mount --bind /dev /mnt/sysimage/dev mount --bind /sys /mnt/sysimage/sys chroot /mnt/sysimage
For CentOS 7 and multipathed root ('/') issue the following before chroot-ing to '/mnt/sysimage':
mount --bind /run /mnt/sysimage/run systemctl start multipathd.service
For CentOS 6:
Create a backup copy of the current initramfs:
cp -p /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img.bak
Now create the initramfs for the current kernel:
dracut -f
If you need to build it for a specific kernel version (replace the version appropriately):
dracut -f /boot/initramfs-2.6.32-358.el6.x86_64.img 2.6.32-358.el6.x86_64
One useful option you might want to add is -H (--hostonly). With this option dracut installs only what is needed for booting your system. Otherwise dracut by default adds many drivers to the initramfs making its size larger than necessary. Many other options may be exercised. Please see man dracut, man dracut.conf and the upstream Deployment Guide.
Reboot
cd / sync telinit 6
umount /cache
pvcreate /dev/vda3
vgextend centos7 /dev/vda3
lvcreate -L 12G -n lv_cache centos7 /dev/vda3
lvcreate -L 12M -n lv_cache_meta centos7 /dev/vda3
lvextend -L 24M /dev/centos7/lv_cache_meta
lvconvert --type cache-pool --cachemode writethrough --poolmetadata centos7/lv_cache_meta centos7/lv_cache
lvs -a -o +devices
lvconvert --type cache --cachepool centos7/lv_cache centos7/root
lvs -a -o +devices
pvs
2 lsblk
3 blkid
4 fdisk /dev/vda
6 partprobe
7 blkid
8 lsblk
9 cat /proc/partitions
10 mkfs.ext4 /dev/vda3
11 e2label /dev/vda3 "LVM Cache"
13 mkdir /storage/cache
14 mount /dev/vda3 /storage/cache
15 blkid -o list
16 cat /etc/fstab
18 yum install nano
19 nano /etc/fstab
20 systemctl daemon-reload
21 mount /storage/cache
22 reboot
Creation -> Logical Volume inside of Partition
fdisk /dev/vdb
pvcreate /dev/vdb2 /dev/vdb1
vgcreate storage /dev/vdb1 /dev/vdb2
lvcreate -n website -L 12G storage /dev/vdb1
mkfs.ext4 /dev/storage/website
e2label /dev/storage/website "Web Storage"
mkdir /storage_data
mount /dev/storage/website /storage_data
- fdisk /dev/vdb
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): p
Disk /dev/vdb: 27.9 GB, 27917287424 bytes, 54525952 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x07abb460
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p):
Using default response p
Partition number (1-4, default 1):
First sector (2048-54525951, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-54525951, default 54525951):
Using default value 54525951
Partition 1 of type Linux and of size 26 GiB is set
Command (m for help): 8e
8: unknown command
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
g create a new empty GPT partition table
G create an IRIX (SGI) partition table
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
- pvcreate /dev/vdb1
Physical volume "/dev/vdb1" successfully created. - vgcreate storage /dev/vdb1
Volume group "storage" successfully created - lvcreate -n rescue -L 25.9G storage /dev/vdb1
Rounding up size to full physical extent 25.90 GiB
Logical volume "rescue" created. - lvdisplay
--- Logical volume ---
LV Path /dev/storage/rescue
LV Name rescue
VG Name storage
LV UUID Dup9lR-m3Iu-rGs4-utWs-Lsmn-3Aii-fks4qe
LV Write Access read/write
LV Creation host, time website.development.hk, 2019-04-12 12:17:09 +0100
LV Status available
# open 0
LV Size 25.90 GiB
Current LE 6631
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:6 - mkfs.xfs /dev/storage/rescue
meta-data=/dev/storage/rescue isize=512 agcount=4, agsize=1697536 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=6790144, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=3315, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0 - lsblk
- mkdir /rescue
- mount /dev/storage/rescue /rescue
- blkid
- man fstab
- nano /etc/fstab
- systemctl daemon-reload