Penjelasan terperinci tentang cakera sistem Linux

1. Klasifikasi cakera

Klasifikasi cakera semasa di pasaran termasuk: cakera IDE (kebanyakannya digunakan dalam PC), cakera SATA, cakera SAS, cakera SSD, dll. Kebanyakan pelayan dalam perusahaan adalah dua yang terakhir, dan cakera SATA kebanyakannya digunakan dalam perniagaan dan Cakera SAS kebanyakannya digunakan untuk perniagaan luaran (beberapa platform perniagaan).

Cakera SATA pada masa ini mempunyai kapasiti maksimum 4T, dan cakera SAS biasanya antara 300G dan 600G Kapasiti ini paling biasa digunakan dalam persekitaran pengeluaran perusahaan Penggunaan cakera dalam pengeluaran sebenar terutamanya bergantung pada keperluan prestasi, iaitu saiz kepantasan membaca dan menulis.

2. Seni bina cakera

Situasi berbilang cakera dalam pelayan peringkat perusahaan

3. Pengiraan kapasiti cakera

Struktur cakera secara amnya termasuk trek, permukaan cakera, sektor, pengepala, dll.

Saiz trek = 512 bait * bilangan sektor

Saiz cakera = saiz trek * bilangan trek

Saiz cakera = saiz cakera * bilangan kepala

Oleh itu, kapasiti cakera = 512 bait * bilangan sektor * bilangan trek * bilangan kepala

4. Pembahagian cakera

Semua maklumat partition cakera disimpan dalam jadual partition Sistem Linux hanya menyokong 4 maklumat jadual partition (partition utama + partition extended) Saiz jadual partition ialah 64 bait

Linux biasanya dibahagikan kepada tiga partition: partition boot, partition swap, /root partition

Nombor partition Linux: partition primer 1-4, partition logik bermula dari 5

Keperluan partition persekitaran pengeluaran sebenar

1 Mesti ada sekurang-kurangnya dua partition: / dan swap

2. Swap (memori maya) = 1.5*saiz memori fizikal Secara amnya, untuk pelayan dengan memori fizikal kurang daripada atau sama dengan 16G, partition swap biasanya ditetapkan terus kepada saiz 16G.

3 Adalah disyorkan untuk menyediakan partition /boot, partition boot Linux, seperti fail kernel, dll. Secara amnya, semua fail hanya bersaiz beberapa dozen M, jadi partition ini boleh ditetapkan kepada 100-200M

.

5. Alat partition cakera fdisk

fdisk adalah untuk kapasiti cakera kurang daripada 2T

[root@cairui ~]# fdisk --help
fdisk: invalid option -- '-'

fdisk: Usage:
fdisk [options] change partition table
fdisk [options] -l list partition table(s)
fdisk -s give partition size(s) in blocks

Options:
-b sector size (512, 1024, 2048 or 4096)
-c switch off DOS-compatible mode
-h print help
-u give sizes in sectors instead of cylinders
-v print version
-C specify the number of cylinders
-H specify the number of heads
-S specify the number of sectors per track

: Success

[root@localhost ~]# fdisk /dev/sda1　　#对/dev/sda1进行分区操作
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x02fadd9c.
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): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition　　#删除一个分区
l list known partition types
m print this menu
n add a new partition　　#新建一个分区
o create a new empty DOS partition table
p print the partition table　　#打印出分区表信息
q quit without saving changes　　#不保存退出
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　　#将分区信息写入分区表并退出程序
x extra functionality (experts only)

Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1): 设置起始柱面
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610):
设置大小或柱面
Using default value 2610
Command (m for help): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
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.
Command (m for help): p 打印分区表信息
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
121 / 753
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb712cc55
Device Boot Start End Blocks Id System
/dev/sdb1 1 2610 20964793+ 83 Linux
分区完成后执行 partprobe 通知系统分区表发生改变
接下来进行格式化分区
[root@Centos ~]# mkfs.ext3 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1310720 inodes, 5241198 blocks
262059 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
160 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
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 24 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@Centos ~]# tune2fs -c -1 /dev/sdb1
tune2fs 1.41.12 (17-May-2010)
Setting maximal mount count to -1
[root@Centos ~]# mount /dev/sdb1 /mnt 挂载分区至/mnt 下
[root@Centos ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 50G 3.5G 44G 8% /
tmpfs 932M 0 932M 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
122 / 753
/dev/mapper/VolGroup-lv_home 26G 215M 24G 1% /home
/dev/sdb1 20G 172M 19G 1% /mnt

6. Alat partition cakera dipisahkan

Disebabkan sekatan persekitaran, adalah mustahil untuk mempunyai cakera bersaiz 2T atau lebih, jadi kami hanya boleh mensimulasikan persekitaran dan menggunakan alat partition parted untuk partition

[root@Centos ~]# parted /dev/sdb mklabel gpt
将磁盘转换成 gpt 的格式
[root@Centos ~]# parted /dev/sdb mkpart primary 0 200（200M）
Warning: The resulting partition is not properly aligned for best
performance.
Ignore/Cancel? Ignore
[root@Centos ~]# parted /dev/sdb p 打印分区表信息
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sdb: 1074MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number Start End Size File system Name Flags
1 17.4kB 200MB 200MB primary
[root@Centos ~]# parted /dev/sdb mkpart primary 201 1073
分区并设置大小
Information: You may need to update /etc/fstab.
[root@Centos ~]# parted /dev/sdb p 打印分区表信息
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sdb: 1074MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number Start End Size File system Name Flags
1 17.4kB 200MB 200MB primary
2 201MB 1073MB 871MB primary
[root@Centos ~]# mkfs.ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
123 / 753
Stride=0 blocks, Stripe width=0 blocks
48960 inodes, 195296 blocks
9764 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67371008
24 block groups
8192 blocks per group, 8192 fragments per group
2040 inodes per group
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729
Writing inode tables: done
Creating journal (4096 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.
[root@Centos ~]# tune2fs -c -1 /dev/sdb1
tune2fs 1.41.12 (17-May-2010)
Setting maximal mount count to -1
[root@Centos ~]# mount /dev/sdb1 /mnt
[root@Centos ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 50G 3.5G 44G 8% /
tmpfs 932M 0 932M 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 26G 215M 24G 1% /home
/dev/sdb1 185M 5.6M 170M 4% /mnt

[root@cairui ~]# parted --help
Usage: parted [OPTION]... [DEVICE [COMMAND [PARAMETERS]...]...]
Apply COMMANDs with PARAMETERS to DEVICE. If no COMMAND(s) are given, run in
interactive mode.

OPTIONs:
-h, --help displays this help message
-l, --list lists partition layout on all block devices
-m, --machine displays machine parseable output
-s, --script never prompts for user intervention
-v, --version displays the version
-a, --align=[none|cyl|min|opt] alignment for new partitions

COMMANDs:
align-check TYPE N check partition N for TYPE(min|opt)
alignment
check NUMBER do a simple check on the file system
cp [FROM-DEVICE] FROM-NUMBER TO-NUMBER copy file system to another partition
help [COMMAND] print general help, or help on
COMMAND
mklabel,mktable LABEL-TYPE create a new disklabel (partition
table)
mkfs NUMBER FS-TYPE make a FS-TYPE file system on
partition NUMBER
mkpart PART-TYPE [FS-TYPE] START END make a partition
mkpartfs PART-TYPE FS-TYPE START END make a partition with a file system
move NUMBER START END move partition NUMBER
name NUMBER NAME name partition NUMBER as NAME
print [devices|free|list,all|NUMBER] display the partition table,
available devices, free space, all found partitions, or a particular
partition
quit exit program
rescue START END rescue a lost partition near START
and END
resize NUMBER START END resize partition NUMBER and its file
system
rm NUMBER delete partition NUMBER
select DEVICE choose the device to edit
set NUMBER FLAG STATE change the FLAG on partition NUMBER
toggle [NUMBER [FLAG]] toggle the state of FLAG on partition
NUMBER
unit UNIT set the default unit to UNIT
version display the version number and
copyright information of GNU Parted

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