我们在运行 Cent OS 7 的生产系统中遇到了一个问题。/（根）分区已达到磁盘空间的 90%，但该机器上没有任何大文件/隐藏文件。请帮助我们解决这个问题。
供你参考：
Version : CentOS Linux release 7.2.1511 (Core).
Machine : Virtual Machine.
df -h 的输出
[root@dbtestlab ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 50G 45G 5.6G 89% /
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 96K 16G 1% /dev/shm
tmpfs 16G 49M 16G 1% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/sdb 493G 146G 322G 32% /logdata
/dev/sdc 493G 181G 287G 39% /dbdata
/dev/mapper/centos-home 442G 212M 442G 1% /home
/dev/sda1 497M 195M 303M 40% /boot
tmpfs 3.2G 16K 3.2G 1% /run/user/1000
tmpfs 3.2G 0 3.2G 0% /run/user/0
du -sch 的输出 *
[root@dbtestlab /]# du -sch *
0 backupdata
0 bin
169M boot
181G dbdata
96K dev
0 disk1
0 disk2
30M etc
179M home
0 lib
0 lib64
146G logdata
0 media
0 mnt
0 opt
du: cannot access ‘proc/13270/task/13270/fd/4’: No such file or directory
du: cannot access ‘proc/13270/task/13270/fdinfo/4’: No such file or directory
du: cannot access ‘proc/13270/fd/4’: No such file or directory
du: cannot access ‘proc/13270/fdinfo/4’: No such file or directory
0 proc
40M root
du: cannot access ‘run/user/1000/gvfs’: Permission denied
49M run
0 sbin
0 srv
0 sys
8.0K tmp
3.8G usr
2.4G var
333G total
分区信息：
[root@dbtestlab /]# cat /proc/partitions
major minor #blocks name
2 0 4 fd0
8 16 524288000 sdb
8 0 524288000 sda
8 1 512000 sda1
8 2 523774976 sda2
8 32 524288000 sdc
8 48 52428800 sdd
11 0 1048575 sr0
253 0 8273920 dm-0
253 1 52428800 dm-1
253 2 463069184 dm-2
磁盘信息
[root@dbtestlab /]# fdisk -l
Disk /dev/sdb: 536.9 GB, 536870912000 bytes, 1048576000 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 /dev/sda: 536.9 GB, 536870912000 bytes, 1048576000 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: dos
Disk identifier: 0x000daca1
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 1048575999 523774976 8e Linux LVM
Disk /dev/sdc: 536.9 GB, 536870912000 bytes, 1048576000 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 /dev/sdd: 53.7 GB, 53687091200 bytes, 104857600 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 /dev/mapper/centos-swap: 8472 MB, 8472494080 bytes, 16547840 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 /dev/mapper/centos-root: 53.7 GB, 53687091200 bytes, 104857600 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 /dev/mapper/centos-home: 474.2 GB, 474182844416 bytes, 926138368 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
编辑1
Inode 使用情况：
[root@dbtestlab /]# df -i
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/mapper/centos-root 23556176 140689 23415487 1% /
devtmpfs 4093940 408 4093532 1% /dev
tmpfs 4097775 9 4097766 1% /dev/shm
tmpfs 4097775 596 4097179 1% /run
tmpfs 4097775 13 4097762 1% /sys/fs/cgroup
/dev/sdb 32768000 37 32767963 1% /logdata
/dev/sdc 32768000 6612 32761388 1% /dbdata
/dev/mapper/centos-home 463069184 207 463068977 1% /home
/dev/sda1 512000 337 511663 1% /boot
tmpfs 4097775 26 4097749 1% /run/user/1000
tmpfs 4097775 1 4097774 1% /run/user/0
编辑2
大于 1 GB 的文件和文件夹
[root@dbtestlab /]# du -xh / 2> /dev/null | grep '[0-9].[0-9]G'
2.1G /var/log
2.4G /var
1.1G /usr/lib64
1.3G /usr/share
3.8G /usr
6.1G /
内核列表：
[root@dbtestlab /]# rpm -q kernel
kernel-3.10.0-123.el7.x86_64
kernel-3.10.0-327.10.1.el7.x86_64
kernel-3.10.0-327.13.1.el7.x86_64
我使用的内核：
[root@dbtestlab /]# uname -a
Linux dbtestlab 3.10.0-327.13.1.el7.x86_64 #1 SMP Thu Mar 31 16:04:38 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
我已经在该机器上安装了 50 GB 的硬盘，但尚未挂载，因为增加 LVM 的大小可能会损坏系统，因为它是根分区。抱歉问题太长，我正在为这个问题寻找解决方案，我发现这些信息对于调试来说必不可少，所以我添加了所有输出状态。如果需要任何其他进一步的信息，请随时询问我。
编辑3
ls -la 的输出：
[root@dbtestlab /]# ls -la
total 52
dr-xr-xr-x. 22 root root 4096 May 30 15:28 .
dr-xr-xr-x. 22 root root 4096 May 30 15:28 ..
-rw-r--r-- 1 root root 0 Apr 7 12:36 .autorelabel
drwxr-xr-x 2 root root 6 Apr 26 12:44 backupdata
lrwxrwxrwx. 1 root root 7 Mar 22 16:56 bin -> usr/bin
dr-xr-xr-x. 4 root root 4096 May 30 15:35 boot
drwxrwxrwx 4 mysql mysql 4096 Apr 8 16:49 dbdata
drwxr-xr-x 19 root root 3320 May 26 23:56 dev
drwxr-xr-x. 2 root root 6 Apr 5 23:22 disk1
drwxr-xr-x. 2 root root 6 Apr 5 23:22 disk2
drwxr-xr-x. 141 root root 8192 May 30 15:33 etc
drwxr-xr-x. 6 root root 4096 May 30 15:59 home
lrwxrwxrwx. 1 root root 7 Mar 22 16:56 lib -> usr/lib
lrwxrwxrwx. 1 root root 9 Mar 22 16:56 lib64 -> usr/lib64
drwxrwxrwx 8 mysql mysql 4096 Apr 9 22:59 logdata
drwxr-xr-x. 2 root root 6 Aug 12 2015 media
drwxr-xr-x. 2 root root 6 Aug 12 2015 mnt
drwxr-xr-x. 3 root root 15 Aug 12 2015 opt
dr-xr-xr-x 250 root root 0 May 26 23:53 proc
dr-xr-x---. 14 root root 4096 May 30 14:37 root
drwxr-xr-x 38 root root 1180 May 30 17:23 run
lrwxrwxrwx. 1 root root 8 Mar 22 16:56 sbin -> usr/sbin
drwxr-xr-x. 2 root root 6 Aug 12 2015 srv
dr-xr-xr-x 13 root root 0 May 26 23:53 sys
drwxrwxrwt. 14 root root 4096 May 31 03:28 tmp
drwxr-xr-x. 13 root root 4096 Mar 22 16:56 usr
drwxr-xr-x. 23 root root 4096 May 26 23:53 var
cat /proc/swaps 的输出
[root@dbtestlab /]# cat /proc/swaps
Filename Type Size Used Priority
/dev/dm-0 partition 8273916 899852 -1
pvdisplay的输出
[root@dbtestlab /]# pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name centos
PV Size 499.51 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 127874
Free PE 0
Allocated PE 127874
PV UUID KP0RnD-kAZ3-sJ0o-B7SH-ePI3-8zig-2Vhmq3
du -sch /* --exclude=/{dev,run,sys,logdata,dbdata,home,boot} 的输出
[root@dbtestlab /]# du -sch /* --exclude=/{dev,run,sys,logdata,dbdata,home,boot}
0 /backupdata
0 /bin
0 /disk1
0 /disk2
30M /etc
0 /lib
0 /lib64
0 /media
0 /mnt
0 /opt
du: cannot access ‘/proc/13991/task/13991/fd/4’: No such file or directory
du: cannot access ‘/proc/13991/task/13991/fdinfo/4’: No such file or directory
du: cannot access ‘/proc/13991/fd/4’: No such file or directory
du: cannot access ‘/proc/13991/fdinfo/4’: No such file or directory
0 /proc
40M /root
0 /sbin
0 /srv
8.0K /tmp
3.8G /usr
2.4G /var
6.1G total