ssd 分区4k对齐 linux,Debian SSD ext4 4K对齐

新入手了一台thinkpad,原来的机械硬盘是500G的, 于是购入一块镁光的MX200 250G的SSD来新装debian stable(jessie)

1,安装系统的之前按住F1进入bios后把模式改为AHCI.

2,用U盘做的启动盘.版本是debian 8.1 AMD64

3,安装系统的时候选择默认推荐分区,也就是一整块

4,debian8 默认是ext4 文件系统.

5,装完后fdisk -lu 发现已经是4K对齐了.

root@debian:/home/tommy# fdisk -lu

Disk /dev/sda: 232.9 GiB, 250059350016 bytes, 488397168 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disklabel type: dos

Disk identifier: 0xa6c609e3

Device    Boot  Start      End  Sectors  Size Id Type

/dev/sda1  *      2048    499711    497664  243M 83 Linux

/dev/sda2      501758 488396799 487895042 232.7G  5 Extended

/dev/sda5      501760 488396799 487895040 232.7G 8e Linux LVM

Disk /dev/mapper/debian--vg-root: 223.2 GiB, 239649947648 bytes, 468066304 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk /dev/mapper/debian--vg-swap_1: 9.5 GiB, 10150215680 bytes, 19824640 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

原来内核>=2.6.3以后ext4就可以直接支持了.

测试下写入

#dd if=/dev/zero of=./largefile bs=1M count=1024

1024+0 records in

1024+0 records out

1073741824 bytes (1.1 GB) copied, 0.800335 s, 1.3 GB/s

#sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"

#dd if=./largefile of=/dev/null bs=4k

262144+0 records in

262144+0 records out

1073741824 bytes (1.1 GB) copied, 4.68755 s, 229 MB/s

这写入速度,1.3GB/s, 读取的速度比较符合接入的是sata2的速度.