Finding the New Hard Drive in CentOS
# ls /dev/sd* /dev/sda /dev/sda1 /dev/sda2 /dev/sdb
Creating Linux Partitions
# su -
# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xd1082b01.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help):
As instructed, switch off DOS compatible mode and change the units to sectors by entering the c and u commands:
Command (m for help): c DOS Compatibility flag is not set Command (m for help): u Changing display/entry units to sectors
In order to view the current partitions on the disk enter the p command:
Command (m for help): p Disk /dev/sdb: 34.4 GB, 34359738368 bytes 255 heads, 63 sectors/track, 4177 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xd1082b01 Device Boot Start End Blocks Id System
As we can see from the above fdisk output, the disk currently has no partitions because it is a previously unused disk. The next step is to create a new partition on the disk, a task which is performed by entering n (for new partition) and p (for primary partition):
Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4):
In this example we only plan to create one partition which will be partition 1. Next we need to specify where the partition will begin and end. Since this is the first partition we need it to start at the first available sector and since we want to use the entire disk we specify the last sector as the end. Note that if you wish to create multiple partitions you can specify the size of each partition by sectors, bytes, kilobytes or megabytes.
Partition number (1-4): 1
First sector (2048-67108863, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-67108863, default 67108863):
Using default value 67108863
Now that we have specified the partition we need to write it to the disk using the w command:
Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. Syncing disks.
If we now look at the devices again we will see that the new partition is visible as /dev/sdb1:
# ls /dev/sd* /dev/sda /dev/sda1 /dev/sda2 /dev/sdb /dev/sdb1
The next step is to create a file system on our new partition.
Creating a File System on a CentOS 6 Disk Partition
# /sbin/mkfs.ext4 -L /backup /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=/backup
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
2097152 inodes, 8388352 blocks
419417 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
256 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
Mounting a File System
# mkdir /backup mount /dev/sdb1 /backup # mount /dev/mapper/vg_CentOS6-lv_root on / type ext4 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0") /dev/sda1 on /boot type ext4 (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw) /dev/sr0 on /media/CentOS_6.0 x86_64 Disc 1 type iso9660 (ro,nosuid,nodev,uhelper=udisks,uid=500,gid=500, iocharset=utf8,mode=0400,dmode=0500) /dev/sdb1 on /backup type ext4 (rw)
Configuring CentOS 6 to Automatically Mount a File System
vim /etc/fstab /dev/mapper/vg_centos6-lv_root / ext4 defaults 1 1 UUID=0d06ebad-ea73-48ad-a50a-1b3b8ef24491 /boot ext4 defaults 1 2 /dev/mapper/vg_centos6-lv_swap swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 LABEL=/backup /backup ext4 defaults 1 2
