Linux 如何查看文件是被那個進程占用寫數(shù)據(jù)？
背景
centos7 在某一段時間監(jiān)控報警磁盤使用率達99%，由于監(jiān)控屬于概要形式信息，沒有快照信息的監(jiān)控（能發(fā)現(xiàn)某進程的I/O，CPU消耗情況），所以需要在服務(wù)器上去定時執(zhí)行統(tǒng)計命令獲取快照信息。
需要通過iostat -dx -k去查看avgqu-sz、await、svctm、%util；
sar -u查看%iowait、%user；
pidstat -d 查看進程I/O讀寫的快照信息
步驟
- 生成統(tǒng)計信息文件
cat>/tmp/at_task.sh<<EOF
pidstat -d 2 >/tmp/pidstat_\`date +%F_%T\`.log 2>& 1 &
sar -u 2 >/tmp/sar_\`date +%F_%T\`.log 2>& 1 &
while [ 1 ];do echo -n \`date +%T\` >>/tmp/iostat_\`date +%F\` 2>& 1 && iostat -dx -k 1 1 >>/tmp/iostat_\`date +%F\` 2>& 1; sleep 2; done &
EOF
在while循環(huán)中使用iostat的原因是要輸出?
?date +%T??時間，不然只有數(shù)據(jù)，沒有時間信息也沒有什么用
- 使用at 命令定時執(zhí)行
at 15:14 today -f /tmp/at_task.sh
出現(xiàn)錯誤
Can't open /var/run/atd.pid to signal atd. No atd running?
重啟atd服務(wù)
service atd restart
重新開啟at定時任務(wù)
at 15:14 today -f /tmp/at_task.sh
job 2 at Wed Mar 13 15:14:00 2019
得到如下快照信息
iostat
15:13:35Linux 3.10.0-862.14.4.el7.x86_64 (ip-xxxxx) 03/13/2019 _x86_64_ (4 CPU)
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
vda 0.12 0.07 17.31 19.41 580.79 90.52 36.57 0.09 2.39 4.42 0.57 0.72 2.63
scd0 0.00 0.00 0.00 0.00 0.00 0.00 6.00 0.00 0.28 0.28 0.00 0.25 0.00
sar
03:14:00 PM CPU %user %nice %system %iowait %steal %idle
03:14:02 PM all 0.25 0.00 0.38 0.00 0.00 99.37
03:14:04 PM all 1.25 0.13 0.63 0.00 0.00 97.99
03:14:06 PM all 0.25 0.13 0.50 0.00 0.00 99.12
03:14:08 PM all 0.50 0.00 0.50 0.63 0.00 98.37
pidstat
03:14:00 PM UID PID kB_rd/s kB_wr/s kB_ccwr/s Command
03:14:02 PM 5700 9089 0.00 6.00 0.00 uxxx
03:14:02 PM 5700 9140 0.00 6.00 0.00 uxxx
03:14:02 PM 5700 9292 0.00 10.00 0.00 uxxx
03:14:02 PM 0 18084 0.00 2.00 0.00 bash
kill 掉收集信息的命令
ps -ef | egrep 'iostat|sar|pidstat|while' | grep -v grep | awk '{print $2}' | xargs -l kill
但ps -ef | egrep 命令沒有獲取到while循環(huán)的pid，不kill掉該while循環(huán)，就會一直對/tmp/iostat_2019-03-13寫數(shù)據(jù)-_-
通過lsof 沒有定位到打開文件的進程
lsof /tmp/iostat_2019-03-13
[root@ip-10-186-60-117 ~]#
[root@ip-10-186-60-117 ~]#
通過lsof 可以定位到打開mysql-error.log的進程
lsof /opt/mysql/data/5690/mysql-error.log
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mysqld 12858 actiontech-universe 1w REG 253,1 6345 20083533 /opt/mysql/data/5690/mysql-error.log
mysqld 12858 actiontech-universe 2w REG 253,1 6345 20083533 /opt/mysql/data/5690/mysql-error.log
可見，某進程只有一只持有某文件的inode，才可以通過lsof查看文件在被那些進程使用
獲取寫文件的進程號
安裝sysemtap
yum -y install systemtap
SystemTap 是對 Linux 內(nèi)核監(jiān)控和跟蹤的工具
利用systemtap中的inodewatch.stp工具來查找寫文件的進程號
得到文件的inode
stat -c '%i' /tmp/iostat_2019-03-13
4210339
獲取文件所在設(shè)備的major，minor
ls -al /dev/vda1
brw-rw---- 1 root disk 253, 1 Jan 30 13:57 /dev/vda1
得到寫文件的pid
stap /usr/share/systemtap/examples/io/inodewatch.stp 253 1 4210339
Checking "/lib/modules/3.10.0-862.14.4.el7.x86_64/build/.config" failed with error: No such file or directory
Incorrect version or missing kernel-devel package, use: yum install kernel-devel-3.10.0-862.14.4.el7.x86_64
根據(jù)系統(tǒng)內(nèi)核版本在kernel-devel rpm build for : Scientific Linux 7網(wǎng)站上下載相應(yīng)的kernal-devel包
wget ftp://ftp.pbone.net/mirror/ftp.scientificlinux.org/linux/scientific/7.2/x86_64/updates/security/kernel-devel-3.10.0-862.14.4.el7.x86_64.rpm
rpm -ivh kernel-devel-3.10.0-862.14.4.el7.x86_64.rpm
再次執(zhí)行stap
stap /usr/share/systemtap/examples/io/inodewatch.stp 253 1 4210339
......
Missing separate debuginfos, use: debuginfo-install kernel-3.10.0-862.14.4.el7.x86_64
Pass 2: analysis failed. [man error::pass2]
Number of similar error messages suppressed: 2.
安裝debuginfo kernal
debuginfo-install kernel-3.10.0-862.14.4.el7.x86_64
Verifying : kernel-debuginfo-common-x86_64-3.10.0-862.14.4.el7.x86_64 1/3
Verifying : yum-plugin-auto-update-debug-info-1.1.31-50.el7.noarch 2/3
Verifying : kernel-debuginfo-3.10.0-862.14.4.el7.x86_64 3/3
Installed:
kernel-debuginfo.x86_64 0:3.10.0-862.14.4.el7
yum-plugin-auto-update-debug-info.noarch 0:1.1.31-50.el7
Dependency Installed:
kernel-debuginfo-common-x86_64.x86_64 0:3.10.0-862.14.4.el7
再次執(zhí)行stap
stap /usr/share/systemtap/examples/io/inodewatch.stp 253 1 4210339
ERROR: module version mismatch (#1 SMP Tue Sep 25 14:32:52 CDT 2018 vs #1 SMP Wed Sep 26 15:12:11 UTC 2018), release 3.10.0-862.14.4.el7.x86_64
WARNING: /usr/bin/staprun exited with status: 1
添加 -v查看詳細報錯
stap -v /usr/share/systemtap/examples/io/inodewatch.stp 253 1 4210339
Pass 1: parsed user script and 471 library scripts using 240276virt/41896res/3368shr/38600data kb, in 300usr/20sys/320real ms.
Pass 2: analyzed script: 2 probes, 12 functions, 8 embeds, 0 globals using 399436virt/196284res/4744shr/197760data kb, in 1540usr/560sys/2106real ms.
Pass 3: using cached /root/.systemtap/cache/f5/stap_f5c0cd780e8a2cac973c9e3ee69fba0c_7030.c
Pass 4: using cached /root/.systemtap/cache/f5/stap_f5c0cd780e8a2cac973c9e3ee69fba0c_7030.ko
Pass 5: starting run.
ERROR: module version mismatch (#1 SMP Tue Sep 25 14:32:52 CDT 2018 vs #1 SMP Wed Sep 26 15:12:11 UTC 2018), release 3.10.0-862.14.4.el7.x86_64
WARNING: /usr/bin/staprun exited with status: 1
Pass 5: run completed in 0usr/10sys/38real ms.
Pass 5: run failed. [man error::pass5]
修改
vim /usr/src/kernels/3.10.0-862.14.4.el7.x86_64/include/generated/compile.h
#define UTS_VERSION "#1 SMP Tue Sep 25 14:32:52 CDT 2018"
改為
#define UTS_VERSION "#1 SMP Wed Sep 26 15:12:11 UTC 2018"
rm -rf /root/.systemtap/cache/f5/stap_f5c0cd780e8a2cac973c9e3ee69fba0c_7030*
再次執(zhí)行
stap /usr/share/systemtap/examples/io/inodewatch.stp 253 1 4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4671) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4677) vfs_write 0xfd00001/4210339
iostat(4683) vfs_write 0xfd00001/4210339
............
可見已經(jīng)得到了寫/tmp/iostat_??date +%F?? 文件的進程號，但進程號一直在打印出來，因為后臺進程iostat -dx -m 的在while循環(huán)中的，每隔sleep 2s 后就會執(zhí)行一次iostat 產(chǎn)生新的pid。
那要怎樣才能讓iostat -dx -m 停止寫/tmp/iostat_??date +%F?? 文件了？除了重啟大法好 $_$
rm -rf 也不能終止后臺的while iostat進程寫文件，刪除了文件后，while循環(huán)又會生成新的文件
rm -rf /tmp/iostat_2019-03-1*
stat /tmp/iostat_2019-03-1*
File: ‘/tmp/iostat_2019-03-13’
Size: 146700 Blocks: 512 IO Block: 4096 regular file
Device: fd01h/64769d Inode: 4210339 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-03-14 16:07:26.211888899 +0800
Modify: 2019-03-14 16:18:17.854019793 +0800
Change: 2019-03-14 16:18:17.854019793 +0800
正確做法
cat>/tmp/iostat.sh<<EOF
while [ 1 ];do echo -n \`date +%T\` >>/tmp/iostat_\`date +%F\` 2>& 1 && iostat -dx -m 1 1 >>/tmp/iostat_\`date +%F\` 2>& 1; sleep 2; done &
EOF
at now + 1 minute today
bash /tmp/iostat.sh
#這樣就能方便的獲取到進程號pid了
ps -ef | grep iostat
root 8593 1 0 16:16 pts/2 00:00:00 bash /tmp/iostat.sh
