这样做，RMAN备份速度可提高6倍！

墨墨导读：本文来自读者投稿，详述一则给客户备份优化的实际案例，通过这次优化，数据库性能提高了6倍。

数据库现状

SQL> select * from v$version;


BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production
CORE  11.2.0.4.0  Production
TNS for Linux: Version 11.2.0.4.0 - Production
NLSRTL Version 11.2.0.4.0 - Production
SQL> set pagesize 0;
select tablespace_name ,sum(bytes)/1024/1024/1024 as GB from dba_data_files group by tablespace_name;
SQL> CMCC10             66.7578125
SYSAUX         .6640625
UNDOTBS1           4.83886719
CMCC3             165.399414
CMCC8             66.7578125
CMCC1             165.399414
CMCC7             66.7578125
USERS             .004882813
CMCC6             165.399414
SYSTEM         .7421875
CMCC2             165.399414
CMCC4             165.399414
CMCC5             165.399414
CMCC9             66.7578125
CMCC11             66.7578125
SQL> alter session set nls_date_format = 'yyyy-mm-dd hh24:mi:ss';
Session altered.
SQL> select max(LAST_ANALYZED) from dba_tables;
2020-02-25 22:20:26

数据文件大小

 du -sh  /test-nvme/oradata/orcl
1.4T  /test-nvme/oradata/orcl

修改linux内核参数shmmax和shmall

修改之前共享内存

[oracle@base-test-01 ~]$ ipcs -m


------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status
0x00000000 114458624  oracle     640        4096       0
0x00000000 114491393  oracle     640        4096       0
0x00000000 114524163  oracle     640        4096       0
0x00000000 1212420    root       644        80         2
0x00000000 1245189    root       644        16384      2
0x00000000 1277958    root       644        280        2
0x00000000 297435143  root       600        524288     2          dest
0x00000000 114556936  oracle     640        4096       0
0x00000000 114589705  oracle     640        4096       0
0x00000000 114622474  oracle     640        4096       0
0x00000000 114655243  oracle     640        4096       0
0x00000000 114688012  oracle     640        4096       0
0x00000000 114720781  oracle     640        4096       0
0x00000000 114753550  oracle     640        4096       0
0x00000000 114786319  oracle     640        4096       0
0x00000000 114819088  oracle     640        4096       0
0x00000000 114851857  oracle     640        4096       0
0x00000000 114884626  oracle     640        4096       0
0x00000000 114917395  oracle     640        4096       0
0x00000000 114950164  oracle     640        4096       0
0x00000000 114982933  oracle     640        4096       0
0x00000000 115015702  oracle     640        4096       0
0x00000000 115048471  oracle     640        4096       0
0x00000000 115081240  oracle     640        4096       0
0x00000000 115114009  oracle     640        4096       0
0x00000000 115146778  oracle     640        4096       0
0x00000000 115179547  oracle     640        4096       0
0x00000000 115212316  oracle     640        4096       0
0x00000000 115245085  oracle     640        4096       0
0x00000000 115277854  oracle     640        4096       0
0x00000000 115310623  oracle     640        4096       0
0x00000000 115343392  oracle     640        4096       0
0x00000000 115376161  oracle     640        4096       0
0x00000000 115408930  oracle     640        4096       0
0x00000000 297762851  root       600        4194304    2          dest
0x00000000 297861156  root       600        524288     2          dest
0x00000000 115441701  oracle     640        4096       0
0x00000000 115474470  oracle     640        4096       0
0x00000000 115507239  oracle     640        4096       0
0x00000000 115540008  oracle     640        4096       0
0x42e38fd0 115572777  oracle     640        4096       0
0x00000000 127959083  root       600        832920     2          dest

修改之前linux内核参数

$ cat /etc/sysctl.conf
# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
#
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
#
# For more information, see sysctl.conf(5) and sysctl.d(5).
fs.aio-max-nr = 1048576
fs.file-max = 6815744
kernel.shmall = 2097152
kernel.shmmax = 4294967295
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
vm.swappiness=1
[oracle@base-test-01 ~]$

修改之后共享内存

[root@base-test-01 oracle]# ipcs -m


------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status
0x00000000 504037376  oracle     640        536870912  72
0x00000000 504070145  oracle     640        107911053312 72
0x42e38fd0 504102915  oracle     640        2097152    72
0x00000000 1212420    root       644        80         2
0x00000000 1245189    root       644        16384      2
0x00000000 1277958    root       644        280        2
0x00000000 297435143  root       600        524288     2          dest
0x00000000 508821513  root       600        832920     2          dest
0x00000000 297762851  root       600        4194304    2          dest
0x00000000 297861156  root       600        524288     2          dest
#  sysresv -l orcl -d on


IPC Resources for ORACLE_SID "orcl" :
Shared Memory:
ID    KEY
504037376  0x00000000
504070145  0x00000000
504102915  0x42e38fd0

修改之后linux内核参数

[root@base-test-01 oracle]# sysctl -p
fs.aio-max-nr = 1048576
fs.file-max = 6815744
kernel.shmall = 67108864
kernel.shmmax = 256000000000
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
vm.swappiness = 1

前后对比

Oracle的共享内存从35个减少到3个，碎片大大减少。

改成异步IO

SQL> SELECT NAME,ASYNCH_IO FROM V$DATAFILE F,V$IOSTAT_FILE I WHERE F.FILE#=I.FILE_NO AND FILETYPE_NAME='Data File';
/test-nvme/oradata/orcl/system01.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/sysaux01.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/undotbs01.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/users01.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc1.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc2.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc3.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc4.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc5.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc6.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc7.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc8.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc9.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc10.dbf       ASYNC_OFF
/test-nvme/oradata/orcl/cmcc11.dbf       ASYNC_OFF
SQL>   alter system set filesystemio_options=setall  scope=spfile;


System altered.
SQL> STARTUP FORCE;
ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance
ORACLE instance started.
Total System Global Area 1.0796E+11 bytes
Fixed Size        2266024 bytes
Variable Size     5.6371E+10 bytes
Database Buffers   5.1540E+10 bytes
Redo Buffers       50450432 bytes
Database mounted.
Database opened.
SQL>  SELECT NAME,ASYNCH_IO FROM V$DATAFILE F,V$IOSTAT_FILE I WHERE F.FILE#=I.FILE_NO AND FILETYPE_NAME='Data File';
/test-nvme/oradata/orcl/system01.dbf       ASYNC_ON
/test-nvme/oradata/orcl/sysaux01.dbf       ASYNC_ON
/test-nvme/oradata/orcl/undotbs01.dbf       ASYNC_ON
/test-nvme/oradata/orcl/users01.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc1.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc2.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc3.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc4.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc5.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc6.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc7.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc8.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc9.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc10.dbf       ASYNC_ON
/test-nvme/oradata/orcl/cmcc11.dbf       ASYNC_ON


15 rows selected.


SQL>

修改成hugepage

过程比较复杂，另外写一个文档。

没有优化前备份性能

修改环境变量，将rman中的时间提示最小单位从天改到秒：

export NLS_DATE_FORMAT=‘YYYY-MM-DD HH24:MI:SS’
export NLS_LANG=AMERICAN_AMERICA.ZHS16GBK   # 或：export NLS_LANG=AMERICAN

rman备份

RMAN>  backup validate database;


Starting backup at 2020-02-26 14:42:44
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00005 name=/test-nvme/oradata/orcl/cmcc1.dbf
input datafile file number=00006 name=/test-nvme/oradata/orcl/cmcc2.dbf
input datafile file number=00007 name=/test-nvme/oradata/orcl/cmcc3.dbf
input datafile file number=00008 name=/test-nvme/oradata/orcl/cmcc4.dbf
input datafile file number=00009 name=/test-nvme/oradata/orcl/cmcc5.dbf
input datafile file number=00010 name=/test-nvme/oradata/orcl/cmcc6.dbf
input datafile file number=00011 name=/test-nvme/oradata/orcl/cmcc7.dbf
input datafile file number=00012 name=/test-nvme/oradata/orcl/cmcc8.dbf
input datafile file number=00013 name=/test-nvme/oradata/orcl/cmcc9.dbf
input datafile file number=00014 name=/test-nvme/oradata/orcl/cmcc10.dbf
input datafile file number=00015 name=/test-nvme/oradata/orcl/cmcc11.dbf
input datafile file number=00003 name=/test-nvme/oradata/orcl/undotbs01.dbf
input datafile file number=00001 name=/test-nvme/oradata/orcl/system01.dbf
input datafile file number=00002 name=/test-nvme/oradata/orcl/sysaux01.dbf
input datafile file number=00004 name=/test-nvme/oradata/orcl/users01.dbf
channel ORA_DISK_1: backup set complete, elapsed time: 00:31:25
.........


RMAN>

从14:42:44开始到15:14:11结束，31分钟27秒，一共1887秒。

从os层查看io情况

$ iostat 60 nvme0n1


Device:            tps    kB_read/s    kB_wrtn/s   kB_read    kB_wrtn
nvme0n1        5091.10    650829.00        93.44   39049740       5606


avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.84    0.00    2.11    0.75    0.00   96.30


Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
nvme0n1        5483.45    701698.13        11.38   42101888        683


avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.93    0.00    2.20    0.72    0.00   96.15


Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
nvme0n1        5589.93    715302.93        12.60   42918176        756


[oracle@base-test-01 ~]$ iostat -x 60 nvme0n1




Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
nvme0n1           0.00     0.00 5255.30    0.93 672465.47     9.53   255.88     1.24    0.24    0.24    0.00   0.16  83.82


avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.77    0.00    2.11    0.73    0.00   96.39


Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
nvme0n1           0.00     0.00 5425.92    1.08 694424.67    11.71   255.92     1.25    0.23    0.23    0.05   0.16  85.25

优化后的备份性能

rman备份

[oracle@base-test-01 ~]$ rman target /


Recovery Manager: Release 11.2.0.4.0 - Production on Wed Feb 26 18:28:40 2020


Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.


connected to target database: ORCL (DBID=1560763823)


RMAN>  backup validate database;


Starting backup at 2020-02-26 18:28:47
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=9391 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00005 name=/test-nvme/oradata/orcl/cmcc1.dbf
input datafile file number=00006 name=/test-nvme/oradata/orcl/cmcc2.dbf
input datafile file number=00007 name=/test-nvme/oradata/orcl/cmcc3.dbf
input datafile file number=00008 name=/test-nvme/oradata/orcl/cmcc4.dbf
input datafile file number=00009 name=/test-nvme/oradata/orcl/cmcc5.dbf
input datafile file number=00010 name=/test-nvme/oradata/orcl/cmcc6.dbf
input datafile file number=00011 name=/test-nvme/oradata/orcl/cmcc7.dbf
input datafile file number=00012 name=/test-nvme/oradata/orcl/cmcc8.dbf
input datafile file number=00013 name=/test-nvme/oradata/orcl/cmcc9.dbf
input datafile file number=00014 name=/test-nvme/oradata/orcl/cmcc10.dbf
input datafile file number=00015 name=/test-nvme/oradata/orcl/cmcc11.dbf
input datafile file number=00003 name=/test-nvme/oradata/orcl/undotbs01.dbf
input datafile file number=00001 name=/test-nvme/oradata/orcl/system01.dbf
input datafile file number=00002 name=/test-nvme/oradata/orcl/sysaux01.dbf
input datafile file number=00004 name=/test-nvme/oradata/orcl/users01.dbf
channel ORA_DISK_1: backup set complete, elapsed time: 00:05:15
List of Datafiles
=================
File Status Marked Corrupt Empty Blocks Blocks Examined High SCN
---- ------ -------------- ------------ --------------- ----------
1    OK     0              15274        97280           10829000
  File Name: /test-nvme/oradata/orcl/system01.dbf
  Block Type Blocks Failing Blocks Processed
  ---------- -------------- ----------------
  Data       0              65126
  Index      0              13578
  Other      0              3302
......


channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
List of Control File and SPFILE
===============================
File Type    Status Blocks Failing Blocks Examined
------------ ------ -------------- ---------------
SPFILE       OK     0              2
Control File OK     0              3146
Finished backup at 2020-02-26 18:34:04

5分钟15秒完成。

从OS层看磁盘的IO性能

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
nvme0n1           0.00     0.02 35998.80    0.45 4607693.07     5.99   255.99    90.92    2.53    2.53    0.41   0.03 100.00


avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.74    0.00    1.23    0.00    0.00   97.03


Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
nvme0n1           0.00     0.00 35901.82    0.45 4595201.33     5.73   255.98    90.03    2.51    2.51    0.44   0.03 100.00


avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.78    0.00    1.24    0.01    0.00   96.98


Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
nvme0n1           0.00     0.00 36015.75    0.52 4609726.14     5.54   255.98    88.58    2.46    2.46    0.26   0.03 100.00


avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.66    0.00    1.19    0.00    0.00   97.14


Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
nvme0n1           0.00     0.00 36069.02    0.58 4616505.08     5.75   255.98    91.41    2.53    2.53    0.23   0.03 100.00

对比分析

项目	优化前	优化后	提高
1.4T全量备份时间	31分钟27秒	5分钟15秒	提高5.99倍
读nvme磁盘的速度	672465.47rkB/s	4607693.07rkB/s	提高6.8倍
iostate中磁盘利用率	80%	100%	提高20%

1. 将同步IO改成异步IO，大大提高IO性能；

2. 修改linux内核参数shmmax和shmall，将共享内存段从35个减少到3个，碎片大大减少；

3. 配置hugepage，Oracle的共享内存管理单位从4K增加到2M，性能大幅提高。

作者：姚远，Oracle 10G和12C OCM，MySQL 5.6 和 5.7 OCP，现在鼎甲公司任顾问，专注于Oracle，MySQL数据库多年。

墨天轮原文链接：https://www.modb.pro/db/25395（复制到浏览器中打开或者点击“阅读原文”）

推荐阅读：144页！分享珍藏已久的数据库技术年刊

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