Linux查看文件系統的掛載時間淺析

我們在Linux系統中如何找到文件系統的掛載時間呢,下麵實驗測試環境為RHEL 6.6，其它Linux版本沒有驗證測試。這個簡單測試了一下常用的ext3/4、xfs、nfs文件系統。

ext文件系統

如果文件系統類型為ext3、ext4（ext2沒有測試，這麼老的文件系統也沒有多少意義了），那麼可以使用命令tune2fs查看文件系統最後一次掛載時間。如下所示：

[root@DB-Server ~]# tune2fs -l /dev/sda1

tune2fs 1.39 (29-May-2006)

Filesystem volume name:   /boot

Last mounted on:          <not available>

Filesystem UUID:          582b189c-396c-4da8-a7a3-1effaa3e4000

Filesystem magic number:  0xEF53

Filesystem revision #:    1 (dynamic)

Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery sparse_super

Default mount options:    user_xattr acl

Filesystem state:         clean

Errors behavior:          Continue

Filesystem OS type:       Linux

Inode count:              26104

Block count:              104388

Reserved block count:     5219

Free blocks:              88252

Free inodes:              26070

First block:              1

Block size:               1024

Fragment size:            1024

Reserved GDT blocks:      256

Blocks per group:         8192

Fragments per group:      8192

Inodes per group:         2008

Inode blocks per group:   251

Filesystem created:       Thu Aug 11 14:28:18 2016

Last mount time:          Tue Feb 12 15:36:22 2019

Last write time:          Tue Feb 12 15:36:22 2019

Mount count:              62

Maximum mount count:      -1

Last checked:             Thu Aug 11 14:28:18 2016

Check interval:           0 (<none>)

Reserved blocks uid:      0 (user root)

Reserved blocks gid:      0 (group root)

First inode:              11

Inode size:               128

Journal inode:            8

Default directory hash:   tea

Directory Hash Seed:      b532c8d4-49b6-4d8a-a2e7-96a415daee37

Journal backup:           inode blocks

如上所示，命令會輸出Last mount time這些信息。

xfs文件系統

如果文件類型是xfs的話，可以在日誌/var/log/messages 中搜索XFS關鍵字。當然也可以搜索Mounting關鍵字，具體測試如下所示：

[root@DB-Server ~]# grep XFS  /var/log/messages

Jul 19 15:03:29 DB-Server kernel: SGI XFS with ACLs, security attributes, large block/inode numbers, no debug enabled

Jul 19 15:03:29 DB-Server kernel: SGI XFS Quota Management subsystem

Jul 19 15:03:29 DB-Server kernel: XFS (sdb): Mounting Filesystem

Jul 19 15:03:29 DB-Server kernel: XFS (sdb): Ending clean mount

Jul 19 15:17:39 DB-Server kernel: XFS (sdb): Mounting Filesystem

Jul 19 15:17:40 DB-Server kernel: XFS (sdb): Ending clean mount

[root@DB-Server ~]# umount /u04

[root@DB-Server ~]# date

Fri Jul 19 15:40:52 CST 2019

[root@DB-Server ~]# mount  -t  xfs  /dev/sdb  /u04

[root@DB-Server ~]# grep XFS  /var/log/messages

Jul 19 15:03:29 DB-Server kernel: SGI XFS with ACLs, security attributes, large block/inode numbers, no debug enabled

Jul 19 15:03:29 DB-Server kernel: SGI XFS Quota Management subsystem

Jul 19 15:03:29 DB-Server kernel: XFS (sdb): Mounting Filesystem

Jul 19 15:03:29 DB-Server kernel: XFS (sdb): Ending clean mount

Jul 19 15:17:39 DB-Server kernel: XFS (sdb): Mounting Filesystem

Jul 19 15:17:40 DB-Server kernel: XFS (sdb): Ending clean mount

Jul 19 15:40:55 DB-Server kernel: XFS (sdb): Mounting Filesystem

Jul 19 15:40:56 DB-Server kernel: XFS (sdb): Ending clean mount

或者搜索Mounting關鍵字，grep -ri Mounting /var/log/* | more

[root@DB-Server ~]# grep -ri Mounting /var/log/* | more

/var/log/anaconda.log:02:10:34,361 INFO    : umounting loopback /tmp/product-disk /dev/loop7

/var/log/boot.log:Remounting root filesystem in read-write mode:  [  OK  ]

/var/log/boot.log:Mounting local filesystems:  [  OK  ]

/var/log/boot.log:Mounting filesystems:  [  OK  ]

/var/log/messages:Jul 19 15:03:29 DB-Server kernel: XFS (sdb): Mounting Filesystem

/var/log/messages:Jul 19 15:17:39 DB-Server kernel: XFS (sdb): Mounting Filesystem

/var/log/messages:Jul 19 15:40:55 DB-Server kernel: XFS (sdb): Mounting Filesystem

[root@DB-Server ~]# 

其實，ext3、ext4 也可以搜索/var/log/messages, 例如可以使用下麵命令（不同版本的Linux可能有所不同，以實際情況為準）

grep EXT4 /var/log/messages

nfs文件系統

如果文件格式是nfs的話，可以用命令 cat /proc/self/mountstats，通過age來判斷，這個表示nfs掛載後的時間，單位為秒。

"age" that specified the time in seconds since the nfs volume was mounted.

cat /proc/self/mountstats命令會輸出age信息，如下所示：

device xxx.xxx.xxx.xxx:/docker mounted on /docker with fstype nfs4 statvers=1.1

    opts: rw,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,acregmin=3,acregmax=60,acdirmin=30,acdirmax=60,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=10.10.5.53,local_lock=none

    age:    23049075

    caps:   caps=0xffdf,wtmult=512,dtsize=32768,bsize=0,namlen=255

    nfsv4:  bm0=0xfdffbfff,bm1=0xf9be3e,bm2=0x0,acl=0x3,pnfs=not configured

    sec:    flavor=1,pseudoflavor=1

    events: 933485 16418086 98 204 247406 29 32837386 50 0 303 0 32337916 494048 30 8084851 56 0 8084831 0 2 46 0 0 0 0 0 0

    bytes:  6359097360 190907 0 0 233464 182715 303 48

    RPC iostats version: 1.0  p/v: 100003/4 (nfs)

    xprt:   tcp 839 0 1 0 19 1983681 1983681 0 4743991 0 37 2150 2760316