Managing Storage

Overview of Storage Hardware

Device files

the device files for disk drives appear in the /dev/ directory.

Device type

sd – the device is SCSI-based

hd – the device is ATA-based

The first hard drive on system may appear as hda or sda

Unit

Following the two-letter device type are one or two letters denoting the specific unit

Partition

the partition on the device is represented by number in the end of device name

/dev/hda1 (ATA drive)

/dev/sdad4 (SCSI device)

Mounting file system

Mounting point

Basically, mounting points are where you mount your file systems or devices.

Seeing What is Mounted

Viewing /etc/mtab

# vi /etc/mtab

The /etc/mtab file is meant to be used to display the status of currently-mounted file systems only. It should not be manually modified.

Viewing /proc/mounts

# vi /proc/mounts

(The Proc psuedo file system is a real time, memory resident file system that tracks the processes running on your machine and the state of your system.)

df – command

Lets we know what file systems are currently mounted and the amount of free space on them.

Filesystem 1K-ブロック 使用 使用可 使用% マウント位置

/dev/mapper/VolGroup00-LogVol00

99636632 10652432 83841264 12% /

/dev/sda1 101086 16258 79609 17% /boot

/dev/mapper/VolGroup00-LogVol02

49611460 1517004 45533640 4% /data

tmpfs 511684 0 511684 0% /dev/shm

Network-Accessible Storage Under Linux

NFS (Network File System)

is a file system that may be accessed via a network connection.

The file systems an NFS server makes available to clients is controlled by the configuration file /etc/exports.

SMB (Server Message Block)

is the name for the communications protocol used by various operating systems produced by Microsoft.

Red Hat Linux supports SMB via the Samba server program.

Mounting File systems automatically with /etc/fstab

#vi /etc/fstab

Mornitoring Disk Space

df – command

# df

-h option for understand by human

Automated Monitoring Using diskcheck

Automatically check disk and send email to administrator.

Adding/Removing Storage

Adding Storage

• Partitioning

  • Using the command-line fdisk utility program

  • Using parted, another command-line utility program

• Formatting the partition(s)

  # mkfs

• Updating /etc/fstab

  to automatically mount to system.

Removing Storage

• Remove the disk drive's partition from /etc/fstab

• Unmount the disk drive's active partitions.

  # umount path

• Erase the contents of the disk drive.

  # badblocks -ws

Disk Quotas

Disk quotas under Red Hat Linux have the following features:

• Per-file-system implementation

• Per-user space accounting

• Per-group space accounting

• Tracks disk block usage

• Tracks disk inode usage

• Hard limits

• Soft limits

• Grace periods