Eu estava tentando determinar um VP ruim que estava fazendo com que o LV reportasse um erro de Buffer I / O e encontrei este comportamento interessante na mensagem "Buffer I / O error".
Em um Large LV mapeado para PVs diferentes, tentei usar o "bloco lógico" informado no erro, para combinar com a tabela dmsetup para descobrir em qual dispositivo de destino estava. No entanto, este método não parece ser confiável.
Eu usei o dmsetup para criar um dispositivo de mapeamento de dispositivo, com um ou vários buracos nele. E as mensagens de erro são muito interessantes e não consigo entender o padrão.
Parece que o número "Logical Block" na mensagem de erro depende do tamanho do buraco e também da sua posição. Existe uma maneira definitiva de localizar o bloqueio ruim real?
Aqui estão os testes que fiz
+++ TESTE 1 bloco de erro em 8, erro de buffer i / o em LB 8
root@ubuntu:~# dmsetup create test x.tab
root@ubuntu:~# dmsetup table test
0 8 linear 8:16 0
8 1 error
9 1000 linear 8:16 8
root@ubuntu:~# dd if=/dev/mapper/test of=/dev/null bs=512 count=1000
dd: error reading ‘/dev/mapper/test’: Input/output error
8+0 records in
8+0 records out
4096 bytes (4.1 kB) copied, 0.000977434 s, 4.2 MB/s
root@ubuntu:~#
Sep 5 17:21:07 ubuntu kernel: [ 1358.811671] bio: create slab <bio-1> at 1
Sep 5 17:21:07 ubuntu kernel: [ 1358.817045] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:07 ubuntu kernel: [ 1358.817192] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:07 ubuntu kernel: [ 1358.817199] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:07 ubuntu kernel: [ 1358.817201] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:07 ubuntu kernel: [ 1358.817203] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:07 ubuntu kernel: [ 1358.817629] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:07 ubuntu kernel: [ 1358.817633] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:07 ubuntu kernel: [ 1358.818649] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:19 ubuntu kernel: [ 1370.324905] Buffer I/O error on device dm-0, logical block 8
Sep 5 17:21:19 ubuntu kernel: [ 1370.325245] Buffer I/O error on device dm-0, logical block 8
+++ TEST 2 bloco de erro em 9, buffer i / o erro em LB 4
root@ubuntu:~# dmsetup create test x.tab
root@ubuntu:~# dmsetup table test
0 9 linear 8:16 0
9 1 error
10 1000 linear 8:16 9
root@ubuntu:~# dd if=/dev/mapper/test of=/dev/null bs=512 count=1000
dd: error reading ‘/dev/mapper/test’: Input/output error
8+0 records in
8+0 records out
4096 bytes (4.1 kB) copied, 0.000630946 s, 6.5 MB/s
root@ubuntu:~#
Sep 5 17:23:28 ubuntu kernel: [ 1499.435904] bio: create slab <bio-1> at 1
Sep 5 17:23:28 ubuntu kernel: [ 1499.440980] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:28 ubuntu kernel: [ 1499.441010] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:28 ubuntu kernel: [ 1499.441037] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:28 ubuntu kernel: [ 1499.441062] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:28 ubuntu kernel: [ 1499.441087] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:28 ubuntu kernel: [ 1499.441314] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:28 ubuntu kernel: [ 1499.441340] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:28 ubuntu kernel: [ 1499.441805] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:53 ubuntu kernel: [ 1524.710414] Buffer I/O error on device dm-0, logical block 4
Sep 5 17:23:53 ubuntu kernel: [ 1524.710572] Buffer I/O error on device dm-0, logical block 4
+++ TEST 3 blocos de erro começam em 1000 por 10 blocos, erro de buffer I / O em LB 500
root@ubuntu:~# dmsetup create test x.tab
root@ubuntu:~# dmsetup table test
0 1000 linear 8:17 0
1000 10 error
1010 1000 linear 8:17 1010
root@ubuntu:~# dd if=/dev/mapper/test of=/dev/null bs=512 count=12000
dd: error reading ‘/dev/mapper/test’: Input/output error
1000+0 records in
1000+0 records out
512000 bytes (512 kB) copied, 0.00278218 s, 184 MB/s
root@ubuntu:~#
Sep 5 17:37:04 ubuntu kernel: [ 2314.961989] bio: create slab <bio-1> at 1
Sep 5 17:37:12 ubuntu kernel: [ 2322.956596] Buffer I/O error on device dm-0, logical block 500
Sep 5 17:37:12 ubuntu kernel: [ 2322.956600] Buffer I/O error on device dm-0, logical block 501
Sep 5 17:37:12 ubuntu kernel: [ 2322.956602] Buffer I/O error on device dm-0, logical block 502
Sep 5 17:37:12 ubuntu kernel: [ 2322.956603] Buffer I/O error on device dm-0, logical block 503
Sep 5 17:37:12 ubuntu kernel: [ 2322.956605] Buffer I/O error on device dm-0, logical block 504
Sep 5 17:37:12 ubuntu kernel: [ 2322.957147] Buffer I/O error on device dm-0, logical block 500
Sep 5 17:37:12 ubuntu kernel: [ 2322.957149] Buffer I/O error on device dm-0, logical block 501
Sep 5 17:37:12 ubuntu kernel: [ 2322.957151] Buffer I/O error on device dm-0, logical block 502
Sep 5 17:37:12 ubuntu kernel: [ 2322.957152] Buffer I/O error on device dm-0, logical block 503
+++ TEST 4 bloco de erro em 1000, erro de buffer I / O em LB 1000
root@ubuntu:~# dmsetup create test x.tab
root@ubuntu:~# dmsetup table test
0 1000 linear 8:17 0
1000 1 error
1001 1000 linear 8:17 1010
root@ubuntu:~# dd if=/dev/mapper/test of=/dev/null bs=512 count=12000
dd: error reading ‘/dev/mapper/test’: Input/output error
1000+0 records in
1000+0 records out
512000 bytes (512 kB) copied, 0.00379868 s, 135 MB/s
root@ubuntu:~#
Sep 5 17:38:48 ubuntu kernel: [ 2419.516088] bio: create slab <bio-1> at 1
Sep 5 17:38:54 ubuntu kernel: [ 2425.506135] Buffer I/O error on device dm-0, logical block 1000
Sep 5 17:38:54 ubuntu kernel: [ 2425.506953] Buffer I/O error on device dm-0, logical block 1000
+++ TESTE 5 blocos de erro começam em 1001 para 2 blocos, buffer de erro de E / S em LB 1001
root@ubuntu:~# dmsetup create test x.tab
root@ubuntu:~# dmsetup table test
0 1001 linear 8:17 0
1001 2 error
1003 1000 linear 8:17 1010
root@ubuntu:~# dd if=/dev/mapper/test of=/dev/null bs=512 count=12000
dd: error reading ‘/dev/mapper/test’: Input/output error
1000+0 records in
1000+0 records out
512000 bytes (512 kB) copied, 0.00362554 s, 141 MB/s
root@ubuntu:~#
Sep 5 17:42:16 ubuntu kernel: [ 2627.373744] bio: create slab <bio-1> at 1
Sep 5 17:42:24 ubuntu kernel: [ 2635.080482] Buffer I/O error on device dm-0, logical block 1001
Sep 5 17:42:24 ubuntu kernel: [ 2635.080486] Buffer I/O error on device dm-0, logical block 1002
Sep 5 17:42:24 ubuntu kernel: [ 2635.081327] Buffer I/O error on device dm-0, logical block 1001
Sep 5 17:42:24 ubuntu kernel: [ 2635.081329] Buffer I/O error on device dm-0, logical block 1002