标签归档：trim置空数据

ssd trim导致fdisk格式化磁盘之后无法恢复

发表于 2023 年 12 月 21 日 由 惜分飞

8个节点的rac,有一个节点有点问题,重装系统的时候,没有选择任何磁盘
20231221191215

结果发现该机器上的所有磁盘都被分区并且加入到centos的vg中了,导致另外7个节点的asm disk的所有磁盘全部异常,磁盘组无法正常mount,在以前正常的rac节点上pvs扫描发现如下结果
20231221191551
对原asm disk(现在被分区加入到vg中的磁盘)进行分析发现所有的ssd磁盘被的以前记录被置空,机械磁盘的数据正常,机械磁盘kfed看到的记录

[root@xxxrac5 oracle]#  kfed read /dev/mapper/hdisk60 aun=2 aus=4096k
kfbh.endian:                          1 ; 0x000: 0x01
kfbh.hard:                          130 ; 0x001: 0x82
kfbh.type:                            3 ; 0x002: KFBTYP_ALLOCTBL
kfbh.datfmt:                          2 ; 0x003: 0x02
kfbh.block.blk:                    2048 ; 0x004: blk=2048
kfbh.block.obj:              2147483682 ; 0x008: disk=34
kfbh.check:                  2349679586 ; 0x00c: 0x8c0d43e2
kfbh.fcn.base:                   998219 ; 0x010: 0x000f3b4b
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
kfdatb.aunum:                    916608 ; 0x000: 0x000dfc80
………………
kfdate[446].free.hi:                  0 ; 0xe1c: S=0 V=0 L=0 ASZM=0x0 S=0
kfdate[447].discriminator:            0 ; 0xe20: 0x00000000
kfdate[447].free.lo.next:             0 ; 0xe20: 0x0000
kfdate[447].free.lo.prev:             0 ; 0xe22: 0x0000
kfdate[447].free.hi:                  0 ; 0xe24: S=0 V=0 L=0 ASZM=0x0 S=0

分析ssd磁盘的记录情况,发现磁盘中记录全部被置空

[root@xxxrac5 oracle]# kfed read /dev/mapper/ssdisk30 aun=2 aus=4096k
kfbh.endian:                          0 ; 0x000: 0x00
kfbh.hard:                            0 ; 0x001: 0x00
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                       0 ; 0x004: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
kfbh.check:                           0 ; 0x00c: 0x00000000
kfbh.fcn.base:                        0 ; 0x010: 0x00000000
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
000800000 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

[root@xxxrac5 oracle]# kfed read /dev/mapper/ssdisk30 aun=11 aus=4096k
kfbh.endian:                          0 ; 0x000: 0x00
kfbh.hard:                            0 ; 0x001: 0x00
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                       0 ; 0x004: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
kfbh.check:                           0 ; 0x00c: 0x00000000
kfbh.fcn.base:                        0 ; 0x010: 0x00000000
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
002C00000 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

[root@xxxrac5 oracle]# kfed read /dev/mapper/ssdisk30 aun=100
kfbh.endian:                          0 ; 0x000: 0x00
kfbh.hard:                            0 ; 0x001: 0x00
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                       0 ; 0x004: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
kfbh.check:                           0 ; 0x00c: 0x00000000
kfbh.fcn.base:                        0 ; 0x010: 0x00000000
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
006400000 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

[root@xxxrac5 oracle]# kfed read /dev/mapper/ssdisk30 aun=1000
kfbh.endian:                          0 ; 0x000: 0x00
kfbh.hard:                            0 ; 0x001: 0x00
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                       0 ; 0x004: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
kfbh.check:                           0 ; 0x00c: 0x00000000
kfbh.fcn.base:                        0 ; 0x010: 0x00000000
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
03E800000 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

[root@xxxrac5 oracle]# kfed read /dev/mapper/ssdisk30 aun=10000
kfbh.endian:                          0 ; 0x000: 0x00
kfbh.hard:                            0 ; 0x001: 0x00
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                       0 ; 0x004: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
kfbh.check:                           0 ; 0x00c: 0x00000000
kfbh.fcn.base:                        0 ; 0x010: 0x00000000
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
271000000 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

[root@xxxrac5 oracle]# kfed read /dev/mapper/ssdisk30 aun=100000
kfbh.endian:                          0 ; 0x000: 0x00
kfbh.hard:                            0 ; 0x001: 0x00
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                       0 ; 0x004: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
kfbh.check:                           0 ; 0x00c: 0x00000000
kfbh.fcn.base:                        0 ; 0x010: 0x00000000
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
186A000000 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

[root@xxxrac5 oracle]# kfed read /dev/mapper/ssdisk30 aun=100000
kfbh.endian:                          0 ; 0x000: 0x00
kfbh.hard:                            0 ; 0x001: 0x00
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                       0 ; 0x004: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
kfbh.check:                           0 ; 0x00c: 0x00000000
kfbh.fcn.base:                        0 ; 0x010: 0x00000000
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
186A000000 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

dd ssd磁盘100M数据压缩前后大小比较(压缩之后只有150kb左右,除了分区和lv信息之外其他全部是0)
100M
20231221193859

通过linux命令查看磁盘是否是为ssd（cat /sys/block/sdfr/queue/rotational为1表示机械磁盘,0表示ssd磁盘）

hdisk66 (360060e8007c550000030c55000000223) dm-66 HITACHI ,OPEN-V          
size=2.0T features='0' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
  |- 10:0:1:4  sdfr               130:208 active ready running
  |- 7:0:0:4   sds                65:32   active ready running
  |- 8:0:1:4   sdu                65:64   active ready running
  `- 9:0:1:4   sdx                65:112  active ready running
ssdisk58 (26e8d69b6480c854f6c9ce90091cfe58e) dm-22 Nimble  ,Server          
size=2.0T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=50 status=active
| `- 7:0:1:48  sdfu               131:0   active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
  `- 10:0:0:48 sdek               128:192 active ghost running
ssdisk43 (2e0e493e08cfd75996c9ce90091cfe58e) dm-8 Nimble  ,Server          
size=2.0T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=50 status=active
| `- 7:0:1:35  sdev               129:112 active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
  `- 10:0:0:35 sddj               71:16   active ghost running
ssdisk60 (2696bc3246f81fb116c9ce90091cfe58e) dm-34 Nimble  ,Server          
size=2.0T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=50 status=active
| `- 7:0:1:59  sdgq               132:96  active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
  `- 10:0:0:59 sdfg               130:32  active ghost running
ssdisk08 (2629f870548db01a76c9ce90091cfe58e) dm-35 Nimble  ,Server          
size=2.0T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=50 status=active
| `- 7:0:1:6   sdcq               69:224  active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
  `- 10:0:0:6  sdz                65:144  active ghost running
[root@odsrac5 oracle]# cat /sys/block/sdcq/queue/rotational
0
[root@odsrac5 oracle]# cat /sys/block/sdcu/queue/rotational
0
[root@odsrac5 oracle]# cat /sys/block/sdfr/queue/rotational
1

出现该问题是由于ssd盘的trim操作导致,相关知识补充:TRIM(SATA), Deallocate(NVMe), UNMAP(SCSI)指的是同一类指令，都是为了减少不必要的数据搬移。
原因：
在文件系统中，删除文件并没有真正的删除物理的数据，只是清空了记录表。而此时，对SSD来说，它并不知道文件已经被删除了，只有下次覆写的时候，SSD才能发现之前被删除的文件对应的page是无效的，从而启动GC。然而，如果在此之前发生了GC等数据搬移动作，无效的page仍然会被当做是有效的。重新磁盘分区,重建文件系统也可能触发类似操作
作用：
Trim 只是一个指令，它让操作系统通知 SSD 主控某个页的数据已经‘无效’后，任务就已完成，并没有更多的操作。TRIM 的先进性在于它可以让固态硬盘在进行垃圾回收的时候跳过移动无用数据的过程，从而不再用重新写入这些无用的数据，达到节省时间的目的。

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