硬碟的常見事情

由 datahunter 在六, 08/09/2012 - 18:52 發表

最後更新: 2015-04-24

介紹

fsck
tune2fs
Bypass a fsck
介分區後看不到新介的分區
找 USB HardDisk
blktrace
重讀 partion table

fsck

-y option will cause the fs-specific fsck to always attempt to fix any detected filesystem corruption automatically. ( 一定要小心用, 可能會出事架 @@!!)

tune2fs

-l: List the contents of the filesystem superblock

tune2fs 1.41.12 (17-May-2010)
Filesystem volume name:   <none>
Last mounted on:          /
Filesystem UUID:          9ae9f254-1a5c-455f-975f-90628cc88386
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              1281120
Block count:              5120000
Reserved block count:     256000
Free blocks:              1953546
Free inodes:              1107416
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1022
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8160
Inode blocks per group:   510
Flex block group size:    16
Filesystem created:       Tue Feb 18 23:31:05 2014
Last mount time:          Wed Feb 19 12:38:06 2014
Last write time:          Wed Feb 19 11:18:40 2014
Mount count:              10
Maximum mount count:      28
Last checked:             Tue Feb 18 23:31:05 2014
Check interval:           15552000 (6 months)
Next check after:         Sun Aug 17 23:31:05 2014
Lifetime writes:          533 MB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
First orphan inode:       661608
Default directory hash:   half_md4
Directory Hash Seed:      f1e66d6f-6636-4619-992d-b03eb383a4d7
Journal backup:           inode blocks

保留幾多空間比 root

-m <percentage> //保留塊的百分比, default 5%

Example:

tune2fs -m 1 /dev/sda3

Setting reserved blocks percentage to 0% (0 blocks)

Checking

Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)

有關 fsck 的設定

-c max-mount-counts <-- 0 or -1 => disregarded by e2fsck(8) and the kernel.

-C mount-count <-- 每次 mount 時會自動 update

Checking

Mount count:              70
Maximum mount count:      -1

P.S.

Enable 它的原因

Bad disk drives, cables, memory, and kernel bugs could all corrupt a filesystem without marking the filesystem dirty

Label

-L volume-label

Errors-behavior

errors-behavior:

continue (Default)
remount-ro
panic

i.e.

# -e errors-behavior

tune2fs -e remount-ro /dev/sdc1

tune2fs 1.42.13 (17-May-2015)
Setting error behavior to 2

Bypass a fsck

touch /forcefsck

它是由 /etc/init.d/checkfs.sh 引發

sudo touch /forcefsck

有機會出現的問題:

touch: cannot touch `/forcefsck': Read-only file system

fsck 的設定

-i <n> N 天 check 一次 // interval-between-checks, m as months, w as weeks, default 6 個月

-c <n> // 每當檔案系統被掛載成讀寫模式時 mount count ++, 當到 n 時, 那就 fsck

-C mount-count // 設置 mount count // 當 -C > -c 時, 下次 reboot就一定會 fsck

-n // fsck to avoid attempting to repair any problems, report problems to stdout

設置開機完全不 fsck

tune2fs -c 0 -i 0 /dev/sdb1

介分區後看不到新介的分區

fdisk -l 看到, 而 ls /dev/sd* 看不到

parted
+ partprobe

Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (Device or resource busy).

As a result, it may not reflect all of your changes until after reboot.

掛載信息

/etc/mtab <-- 已掛載的分區信息

/etc/fstab

獲得 HardDisk 的 UUID

ls -l /dev/disk/by-uuid/

vol_id /dev/sda1

blkid /dev/sda1

not aligned

parted: "The resulting partition is not aligned... "

Modern HDD starting after about 1TB can use 4kB physical sectors.

Its important for performance that filesystems are aligned on 4kB boundaries,

as the drive will do read/modify/write to fake 512B physical sectors.

找 USB HardDisk

找出本機的 Block Device

ls /sys/block

lsblk

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 232.9G  0 disk
├─sda1   8:1    0    94M  0 part /boot
├─sda2   8:2    0   9.3G  0 part /
├─sda3   8:3    0   1.9G  0 part [SWAP]
├─sda4   8:4    0     1K  0 part
├─sda5   8:5    0  18.5G  0 part
├─sda6   8:6    0  18.6G  0 part
├─sda7   8:7    0  18.6G  0 part
├─sda8   8:8    0  18.6G  0 part
└─sda9   8:9    0  44.7G  0 part /mnt/vm

是不是 hotplug 的 Disk ?

cat /sys/block/sd*/removable

lsscsi:

apt-get install lsscsi

lsscsi

[0:0:0:0]    disk    ATA      Hitachi HDP72502 GM2O  /dev/sd

ls -al /dev/disk/by-id/

total 0
lrwxrwxrwx 1 root root  9 Oct 24 08:51 scsi-3600508e000000000cc17b439c8f08602 -> ../../sda
lrwxrwxrwx 1 root root 10 Oct 24 08:51 scsi-3600508e000000000cc17b439c8f08602-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 Oct 24 08:51 scsi-3600508e000000000cc17b439c8f08602-part2 -> ../../sda2
lrwxrwxrwx 1 root root 10 Oct 24 08:51 scsi-3600508e000000000cc17b439c8f08602-part3 -> ../../sda3
lrwxrwxrwx 1 root root  9 Oct 24 08:51 usb-BUFFALO_External_HDD_0000000204019FA -> ../../sdc
lrwxrwxrwx 1 root root 10 Oct 24 08:51 usb-BUFFALO_External_HDD_0000000204019FA-part1 -> ../../sdc1
lrwxrwxrwx 1 root root  9 Oct 24 08:51 usb-BUFFALO_External_HDD_00000002E077D26 -> ../../sdb
lrwxrwxrwx 1 root root 10 Oct 24 08:51 usb-BUFFALO_External_HDD_00000002E077D26-part1 -> ../../sdb1

blktrace

用它可以獲得以下資訊

sync
read
write
queue
requeue
issue
complete

安裝:

apt-get install blktrace

使用:

blktrace -a write /dev/sda5

重讀 partion table

partprobe /dev/sdX

相當於

echo 1 > /sys/block/sdd/device/rescan

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