刚申请的用于XenServer虚拟化测试服务器已于昨天到手，基本存储配置为：
- 1 × 三星960 EVO 250G M.2 NVMe PCI-E固态硬盘，计划安装XenServer系统
- 6 × 西部数据 SATA 3.0 6Gb/s 2T机械硬盘，计划组装RAID
XenServer安装完成后，发现操作系统的用量很少，50G都不到，那么还有近200G的空间是可以使用的。关键这是一块M.2 PCI-E的固态硬盘啊，并非普通的固态硬盘，读写速度是常规SSD的10倍。
# fdisk -l /dev/nvme0n1
WARNING: fdisk GPT support is currently new, and therefore in an experimental phase.
Use at your own discretion.
Disk /dev/nvme0n1: 250.1 GB, 250059350016 bytes, 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: gpt
# Start End Size Type Name
1 46139392 83888127 18G Microsoft basic
2 8390656 46139391 18G Microsoft basic
3 83888128 84936703 512M BIOS boot parti
5 2048 8390655 4G Microsoft basic
6 84936704 87033855 1G Linux swap
京东上关于“三星960 EVO 250G”固态硬盘的参数说明：
反正是台虚拟化测试机器，硬盘又有那么高的读写速度，这部分闲置的空间可不能浪费啊，要好好利用，最简单的就是做文件共享。
还有一点，通过fdisk -l命令查看到的M2 SSD硬盘的分区格式是GPT，并非传统的MBR分区模式。在Linux下，fdisk工具不支持GPT，得使用另一个GUN发布的强大分区工具parted。
# parted
GNU Parted 3.1
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) help
align-check TYPE N check partition N for TYPE(min|opt) alignment
help [COMMAND] print general help, or help on COMMAND
mklabel,mktable LABEL-TYPE create a new disklabel (partition table)
mkpart PART-TYPE [FS-TYPE] START END make a partition
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
rm NUMBER delete partition NUMBER
select DEVICE choose the device to edit
disk_set FLAG STATE change the FLAG on selected device
disk_toggle [FLAG] toggle the state of FLAG on selected device
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
选择要操作的M2 SSD硬盘：
(parted) select /dev/nvme0n1
Using /dev/nvme0n1
查看磁盘的分区表信息及未分配磁盘空间，可以看到，该SSD磁盘还有205G的空间未分配，这也正是我想要利用的一部分空间。
(parted) print free
Model: Unknown (unknown)
Disk /dev/nvme0n1: 250GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: pmbr_boot
Number Start End Size File system Name Flags
17.4kB 1049kB 1031kB Free Space
5 1049kB 4296MB 4295MB ext3
2 4296MB 23.6GB 19.3GB
1 23.6GB 43.0GB 19.3GB ext3
3 43.0GB 43.5GB 537MB bios_grub, legacy_boot
6 43.5GB 44.6GB 1074MB linux-swap(v1)
44.6GB 250GB 205GB Free Space
创建一个文件系统为ext3格式的主分区，并把剩余空闲空间全部分给该分区。注意结尾处是“-1s”，表示要划分空间的结尾是磁盘的最后一个扇区。过程中parted工具会自动调整扇区分配信息，输入“Yes”表示同意，如果输入的是“No”，则会忽略创建分区。若是要创建指定空间的新分区，例如要创建100GB的分区，则命令为：mkpart primary ext3 44.6GB 144.6GB
(parted) mkpart primary ext3 44.6GB -1s
Warning: You requested a partition from 44.6GB to 250GB (sectors 87109375..488397167).
The closest location we can manage is 44.6GB to 250GB (sectors 87033856..488397134).
Is this still acceptable to you?
Yes/No? Yes
(parted) print free
Model: Unknown (unknown)
Disk /dev/nvme0n1: 250GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: pmbr_boot
Number Start End Size File system Name Flags
17.4kB 1049kB 1031kB Free Space
5 1049kB 4296MB 4295MB ext3
2 4296MB 23.6GB 19.3GB
1 23.6GB 43.0GB 19.3GB ext3
3 43.0GB 43.5GB 537MB bios_grub, legacy_boot
6 43.5GB 44.6GB 1074MB linux-swap(v1)
4 44.6GB 250GB 205GB ext3 primary
新分区创建完后，就可以退出parted分区操作了，然后再对新分区进行格式化：
(parted) quit
Information: You may need to update /etc/fstab.
新分区格式化。这里要注意分区的编号，其组成格式为：磁盘路径+小写字母p+要格式化的GPT分区编号。
# mkfs.ext3 /dev/nvme0n1p4
mke2fs 1.42.9 (28-Dec-2013)
Discarding device blocks: done
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
12550144 inodes, 50170409 blocks
2508520 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
1532 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, 11239424, 20480000, 23887872
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
查看分区情况：
# fdisk -l /dev/nvme0n1
WARNING: fdisk GPT support is currently new, and therefore in an experimental phase.
Use at your own discretion.
Disk /dev/nvme0n1: 250.1 GB, 250059350016 bytes, 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: gpt
# Start End Size Type Name
1 46139392 83888127 18G Microsoft basic
2 8390656 46139391 18G Microsoft basic
3 83888128 84936703 512M BIOS boot parti
4 87033856 488397134 191.4G Microsoft basic primary
5 2048 8390655 4G Microsoft basic
6 84936704 87033855 1G Linux swap
最后就是挂载分区了：
# mkdir -p /nfs0252
# mount -t ext3 /dev/nvme0n1p4 /nfs0252
# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 320M 0 320M 0% /dev
tmpfs 330M 72K 330M 1% /dev/shm
tmpfs 330M 924K 329M 1% /run
tmpfs 330M 0 330M 0% /sys/fs/cgroup
/dev/nvme0n1p1 18G 1.7G 16G 10% /
xenstore 330M 0 330M 0% /var/lib/xenstored
/dev/loop0 55M 55M 0 100% /var/xen/xc-install
/dev/nvme0n1p5 3.9G 13M 3.7G 1% /var/log
tmpfs 66M 0 66M 0% /run/user/0
/dev/nvme0n1p4 189G 60M 179G 1% /nfs0252
设置开机自动挂载：
# vi /etc/fstab，新增挂载配置：
/dev/nvme0n1p4 /nfs0252 ext3 defaults 0 0