1)需求说明
在虚拟机中,我们在服务器开机的状态下添加新的磁盘或者说从存储上映射某个LUN区域给服务器,不重启系统的情况下,往往不能够直接识别到磁盘,在遇到这种情况的时候,我们可以让系统重新扫描让服务器重新识别到磁盘。
2)处理步骤
下面看一下在系统不重启的情况,如何让系统认识新的磁盘,并能对其分区与格式化
1、在开机状态下新增磁盘
2、执行下面的命令
echo "- – -" > /sys/class/scsi_host/host0/scan
特别注意
① “- – -” 这三个-之间是有空格的
② 假如 fdisk -l 还是未发现新硬盘,则将上面命令中的host0,替换为host1,host2,….看看
我们再查看系统日志/var/log/messages,发现对SCSI设备进行了一次重新扫描,用fdisk -l也看到了新增加的磁盘了。上面的命令主要的目的就是scan the SCSI bus。
3)操作步骤
a、查看磁盘分区信息(这里我们在虚拟机中已经添加了磁盘)
[root@localhost ~]# fdisk -l 磁盘 /dev/sda:107.4 GB, 107374182400 字节,209715200 个扇区 Units = 扇区 of 1 * 512 = 512 bytes 扇区大小(逻辑/物理):512 字节 / 512 字节 I/O 大小(最小/最佳):512 字节 / 512 字节 磁盘标签类型:dos 磁盘标识符:0x00039749 设备 Boot Start End Blocks Id System /dev/sda1 * 2048 1026047 512000 83 Linux /dev/sda2 1026048 105883647 52428800 83 Linux /dev/sda3 105883648 114010111 4063232 82 Linux swap / Solaris /dev/sda4 114010112 209715199 47852544 5 Extended /dev/sda5 114012160 134983679 10485760 83 Linux
b、执行操作指令
[root@localhost ~]# cd /sys/class/scsi_host/ [root@localhost scsi_host]# ls host0 host1 host2 [root@localhost scsi_host]# echo "- - -" > /sys/class/scsi_host/host0/scan
c、再次查看磁盘的分区信息
[root@localhost scsi_host]# fdisk -l 磁盘 /dev/sda:107.4 GB, 107374182400 字节,209715200 个扇区 Units = 扇区 of 1 * 512 = 512 bytes 扇区大小(逻辑/物理):512 字节 / 512 字节 I/O 大小(最小/最佳):512 字节 / 512 字节 磁盘标签类型:dos 磁盘标识符:0x00039749 设备 Boot Start End Blocks Id System /dev/sda1 * 2048 1026047 512000 83 Linux /dev/sda2 1026048 105883647 52428800 83 Linux /dev/sda3 105883648 114010111 4063232 82 Linux swap / Solaris /dev/sda4 114010112 209715199 47852544 5 Extended /dev/sda5 114012160 134983679 10485760 83 Linux 磁盘 /dev/sdb:21.5 GB, 21474836480 字节,41943040 个扇区 Units = 扇区 of 1 * 512 = 512 bytes 扇区大小(逻辑/物理):512 字节 / 512 字节 I/O 大小(最小/最佳):512 字节 / 512 字节 磁盘 /dev/sdc:21.5 GB, 21474836480 字节,41943040 个扇区 Units = 扇区 of 1 * 512 = 512 bytes 扇区大小(逻辑/物理):512 字节 / 512 字节 I/O 大小(最小/最佳):512 字节 / 512 字节 磁盘 /dev/sdd:21.5 GB, 21474836480 字节,41943040 个扇区 Units = 扇区 of 1 * 512 = 512 bytes 扇区大小(逻辑/物理):512 字节 / 512 字节 I/O 大小(最小/最佳):512 字节 / 512 字节 磁盘 /dev/sde:21.5 GB, 21474836480 字节,41943040 个扇区 Units = 扇区 of 1 * 512 = 512 bytes 扇区大小(逻辑/物理):512 字节 / 512 字节 I/O 大小(最小/最佳):512 字节 / 512 字节
经过对比,可以发现,磁盘已经被识别了!
d、查看日志相关的信息
[root@localhost scsi_host]# tail -20 /var/log/messages Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] 41943040 512-byte logical blocks: (21.4 GB/20.0 GiB) Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] Write Protect is off Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] Cache data unavailable Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] Assuming drive cache: write through Jul 18 15:49:19 localhost kernel: sdb: unknown partition table Jul 18 15:49:19 localhost kernel: sd 0:0:2:0: [sdc] Attached SCSI disk Jul 18 15:49:19 localhost kernel: scsi target0:0:4: Domain Validation skipping write tests Jul 18 15:49:19 localhost kernel: scsi target0:0:4: Ending Domain Validation Jul 18 15:49:19 localhost kernel: scsi target0:0:4: FAST-40 WIDE SCSI 80.0 MB/s ST (25 ns, offset 127) Jul 18 15:49:19 localhost kernel: sd 0:0:1:0: [sdb] Attached SCSI disk Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] 41943040 512-byte logical blocks: (21.4 GB/20.0 GiB) Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] Write Protect is off Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] Cache data unavailable Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] Assuming drive cache: write through Jul 18 15:49:19 localhost kernel: sdd: unknown partition table Jul 18 15:49:19 localhost kernel: sde: unknown partition table Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] Attached SCSI disk Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] Attached SCSI disk Jul 18 15:50:01 localhost systemd: Starting Session 132 of user root. Jul 18 15:50:01 localhost systemd: Started Session 132 of user root. [root@localhost scsi_host]# tail -40 /var/log/messages Jul 18 15:49:18 localhost kernel: sd 0:0:1:0: [sdb] Write Protect is off Jul 18 15:49:18 localhost kernel: sd 0:0:1:0: [sdb] Cache data unavailable Jul 18 15:49:18 localhost kernel: sd 0:0:1:0: [sdb] Assuming drive cache: write through Jul 18 15:49:18 localhost kernel: scsi 0:0:2:0: Direct-Access VMware, VMware Virtual S 1.0 PQ: 0 ANSI: 2 Jul 18 15:49:18 localhost kernel: scsi target0:0:2: Beginning Domain Validation Jul 18 15:49:19 localhost kernel: scsi target0:0:2: Domain Validation skipping write tests Jul 18 15:49:19 localhost kernel: scsi target0:0:2: Ending Domain Validation Jul 18 15:49:19 localhost kernel: scsi target0:0:2: FAST-40 WIDE SCSI 80.0 MB/s ST (25 ns, offset 127) Jul 18 15:49:19 localhost kernel: scsi 0:0:3:0: Direct-Access VMware, VMware Virtual S 1.0 PQ: 0 ANSI: 2 Jul 18 15:49:19 localhost kernel: scsi target0:0:3: Beginning Domain Validation Jul 18 15:49:19 localhost kernel: scsi target0:0:3: Domain Validation skipping write tests Jul 18 15:49:19 localhost kernel: scsi target0:0:3: Ending Domain Validation Jul 18 15:49:19 localhost kernel: scsi target0:0:3: FAST-40 WIDE SCSI 80.0 MB/s ST (25 ns, offset 127) Jul 18 15:49:19 localhost kernel: scsi 0:0:4:0: Direct-Access VMware, VMware Virtual S 1.0 PQ: 0 ANSI: 2 Jul 18 15:49:19 localhost kernel: scsi target0:0:4: Beginning Domain Validation Jul 18 15:49:19 localhost kernel: sd 0:0:2:0: [sdc] 41943040 512-byte logical blocks: (21.4 GB/20.0 GiB) Jul 18 15:49:19 localhost kernel: sd 0:0:2:0: [sdc] Write Protect is off Jul 18 15:49:19 localhost kernel: sd 0:0:2:0: [sdc] Cache data unavailable Jul 18 15:49:19 localhost kernel: sd 0:0:2:0: [sdc] Assuming drive cache: write through Jul 18 15:49:19 localhost kernel: sdc: unknown partition table Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] 41943040 512-byte logical blocks: (21.4 GB/20.0 GiB) Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] Write Protect is off Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] Cache data unavailable Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] Assuming drive cache: write through Jul 18 15:49:19 localhost kernel: sdb: unknown partition table Jul 18 15:49:19 localhost kernel: sd 0:0:2:0: [sdc] Attached SCSI disk Jul 18 15:49:19 localhost kernel: scsi target0:0:4: Domain Validation skipping write tests Jul 18 15:49:19 localhost kernel: scsi target0:0:4: Ending Domain Validation Jul 18 15:49:19 localhost kernel: scsi target0:0:4: FAST-40 WIDE SCSI 80.0 MB/s ST (25 ns, offset 127) Jul 18 15:49:19 localhost kernel: sd 0:0:1:0: [sdb] Attached SCSI disk Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] 41943040 512-byte logical blocks: (21.4 GB/20.0 GiB) Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] Write Protect is off Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] Cache data unavailable Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] Assuming drive cache: write through Jul 18 15:49:19 localhost kernel: sdd: unknown partition table Jul 18 15:49:19 localhost kernel: sde: unknown partition table Jul 18 15:49:19 localhost kernel: sd 0:0:3:0: [sdd] Attached SCSI disk Jul 18 15:49:19 localhost kernel: sd 0:0:4:0: [sde] Attached SCSI disk Jul 18 15:50:01 localhost systemd: Starting Session 132 of user root. Jul 18 15:50:01 localhost systemd: Started Session 132 of user root.
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