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检查分区是否正确对齐以提高性能？

tag-icon • tag-icon partition performance gpt parted partition-table
检查分区是否正确对齐以提高性能？

我刚刚为硬盘 ( /dev/sda) 上的整个空间创建了一个 GPT 磁盘标签，如下所示：

# parted

(parted) select /dev/sda
(parted) mklabel gpt
Warning: The existing disk label on /dev/sda will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes/No? Y
(parted) mkpart primary 0% 100%
Warning: The resulting partition is not properly aligned for best performance.
Ignore/Cancel? I
(parted) quit

现在进一步阅读，我意识到“忽略”对于性能来说可能是一个坏主意。

但...

# parted

(parted) print
Model: ATA ST33000650NS (scsi)
Disk /dev/sda: 3001GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name  Flags
 5      1049kB  2097kB  1049kB                     bios_grub
 1      2097kB  8592MB  8590MB                     raid
 2      8592MB  9129MB  537MB                      raid
 3      9129MB  43.5GB  34.4GB                     raid
 4      43.5GB  3001GB  2957GB                     raid

(parted) align-check optimal 1
1 aligned
(parted) align-check optimal 2
2 aligned
(parted) align-check optimal 3
3 aligned
(parted) align-check optimal 4
4 aligned
(parted) align-check optimal 5
5 aligned
(parted)

那么parted分区是自己对齐的吗？align-check optimal *这么说。

  1. 如果不是这种情况，如何检查磁盘的分区是否需要重新对齐以提高性能？我该怎么做呢？

  2. 如果确实如此，mkpart primary 0% 100%实际上会在所有情况下自动执行对齐分区的过程吗？有什么边缘情况不会发生吗？

答案1

parted从该选项开始--align optimal告诉程序与设备物理块大小的倍数对齐以确保最佳性能。

该--align选项还有其他类型可用。

请参阅man parted获取更多信息。

答案2

我刚刚在centos 6.7的虚拟机上测试：

# parted /dev/sdb 
GNU Parted 2.1
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print
Error: /dev/sdb: unrecognised disk label                                  
(parted) mklabel gpt                                                      
(parted) mkpart primary 1m 100%
(parted) quit                                                             
Information: You may need to update /etc/fstab.                           

[root@localhost ~]# parted /dev/sdb print 
Model: VMware Virtual disk (scsi)
Disk /dev/sdb: 1074MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name     Flags
 1      1049kB  1073MB  1072MB               primary

[root@localhost ~]# parted /dev/sdb "unit s print"
Model: VMware Virtual disk (scsi)
Disk /dev/sdb: 2097152s
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start  End       Size      File system  Name     Flags
 1      2048s  2095103s  2093056s               primary

这样，gpt 分区就正确对齐了。

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