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孤星119:
好熟悉的数据库字段啊, 上家公司做的项目每天都跟这些字段打招呼 ...
Oracle exp compress参数引起的空间浪费 -
itspace:
quxiaoyong 写道遇到个问题,网上一搜,全他妈这篇文章 ...
数据库连接错误ORA-28547 -
quxiaoyong:
遇到个问题,网上一搜,全他妈这篇文章。你转来转去的有意思吗?
数据库连接错误ORA-28547 -
hctech:
关于version count过高的问题,不知博主是否看过ey ...
某客户数据库性能诊断报告 -
itspace:
invalid 写道写的不错,我根据这个来安装,有点理解错误了 ...
AIX 配置vncserver
Aix平台打开异步io需要fileset支持
查看异步io是否已经打开,available表示已经开启
当然也可以通过以下命令启用aio
修改maxreqs时报如下错误
解决办法如下
可以仔细了解一下-P参数的作用
查看aio进程数
查看目前系统异步io是否遇到瓶颈
下面的列表描述了用于监视 AIO 子系统的一些参数。
* avfc:这个参数用于报告在指定的时间间隔内每秒的平均快速路径请求计数。
* avgc:这个参数用于报告在指定的时间间隔内每秒的平均全局异步 I/O 请求。
* maxgc:这个参数用于报告从上一次获取这个值以来最大的全局异步 I/O 请求。
* maxfc:这个参数用于报告从上一次获取这个值以来快速路径请求计数的最大值。
* maxreqs:这个参数是允许的、异步 I/O 请求的最大值。
在我们的示例中,AIO 服务器不是系统瓶颈。
需要注意的是在AIX 6L中异步io会自动开启,maxreqsminservers、maxservers也会根据应用而自动调整,无须人工干预,当然也没有smitty aio这条命令了,呵呵
附:metalink的说明
Solution
AIX 5L supports asynchronous I/O (AIO) for database files created both on file system partitions and on raw devices.
AIO on raw devices is implemented fully into the AIX kernel, and does not require database processes to service the AIO requests.
When using AIO on file systems, the kernel database processes (aioserver) control each request from the time a request is taken off the queue to the time it is completed. The number of aioserver servers determines the number of AIO requests that can be processed in the system concurrently. So, it is important to tune the number of aioserver processes when using file systems to store Oracle Database data files.
Use one of the following commands to set the number of servers. This applies only when using
asynchronous I/O on file systems rather than raw devices:
smit aio
chdev -l aio0 -a maxservers=' m ' -a minservers='n'
Set the minimum value to the number of servers to be started when the system is started. Set the maximum value to the number of servers that can be started in response to a large number of concurrent requests. These parameters apply to file systems only. They do not apply to raw devices.
The default value for the minimum number of servers is 1. The default value for the maximum number of servers is 10. These values are usually too low to run Oracle Database on large systems with 4 CPUs or more, if you are not using kernelized AIO. Oracle recommends that you set the parameters to the values listed in the following table.
Parameter Values
=============
minservers
Oracle recommends an initial value equal to the number of CPUs on the system or 10, whichever is lower.
maxservers
Starting with AIX 5L version 5.2, this parameter counts the maximum number of AIO servers per CPU. On previous versions of AIX, it was a systemwide value. If you are using GPFS, then set maxservers to worker1threads divided by the number of CPUs. This is the optimal setting.
Increasing maxservers does not lead to improved I/O performance. If you are using JFS/JFS2, then set the initial value to 10 times the number of logical disks divided by the number of CPUs.
Monitor the actual number of aioservers started during a typical workload using the pstat or ps commands. If the actual number of active aioservers is equal to the maxservers, then increase the maxservers value.
maxreqs
Set the initial value to 4 times the number of logical disks multiplied by the queue depth. You can determine the queue depth by running the following command:
$ lsattr -E -l hdiskxx
Typically, the queue depth is 3.
If the value of the maxservers or maxreqs parameter is set too low, then the following warning messages are repeatedly displayed:
"Warning: lio_listio returned EAGAIN
Performance degradation may be seen."
You can avoid these errors by increasing the value of the maxservers parameter. To display the number of AIO servers running, enter the following commands as the root user:
# pstat -a | grep -c aios
# ps -k | grep aioserver
Check the number of active AIO servers periodically, and change the values of the minservers and maxservers parameters if required. The changes take place when the system is restarted.
引用
# lslpp -l bos.rte.aio
Fileset Level State Description
----------------------------------------------------------------------------
Path: /usr/lib/objrepos
bos.rte.aio 5.3.0.60 COMMITTED Asynchronous I/O Extension
Path: /etc/objrepos
bos.rte.aio 5.3.0.60 COMMITTED Asynchronous I/O Extension
Fileset Level State Description
----------------------------------------------------------------------------
Path: /usr/lib/objrepos
bos.rte.aio 5.3.0.60 COMMITTED Asynchronous I/O Extension
Path: /etc/objrepos
bos.rte.aio 5.3.0.60 COMMITTED Asynchronous I/O Extension
查看异步io是否已经打开,available表示已经开启
引用
# lsattr -El aio0
autoconfig available STATE to be configured at system restart True
fastpath enable State of fast path True
kprocprio 39 Server PRIORITY True
maxreqs 4096 Maximum number of REQUESTS True
maxservers 10 MAXIMUM number of servers per cpu True
minservers 1 MINIMUM number of servers True
autoconfig available STATE to be configured at system restart True
fastpath enable State of fast path True
kprocprio 39 Server PRIORITY True
maxreqs 4096 Maximum number of REQUESTS True
maxservers 10 MAXIMUM number of servers per cpu True
minservers 1 MINIMUM number of servers True
引用
# aioo -a
minservers = 1
maxservers = 10
maxreqs = 4096
fsfastpath = 0
minservers = 1
maxservers = 10
maxreqs = 4096
fsfastpath = 0
当然也可以通过以下命令启用aio
引用
# chdev -P -l aio0 -a autoconfig='available'
aio0 changed
aio0 changed
修改maxreqs时报如下错误
引用
# chdev -l aio0 -a maxreqs=16384
Method error (/usr/lib/methods/chgaio):
0514-064 Cannot perform the requested function because the
AIO kernel extension is permanent and cannot be unloaded.
Method error (/usr/lib/methods/chgaio):
0514-064 Cannot perform the requested function because the
AIO kernel extension is permanent and cannot be unloaded.
解决办法如下
引用
# chdev -l aio0 -P -a maxreqs=16384
aio0 changed
aio0 changed
可以仔细了解一下-P参数的作用
引用
-P
Changes the device's characteristics permanently in the Customized Devices object class without actually changing the device.This is useful for devices that cannot be made unavailable and cannot be changed while in the available state. The change ismade to the database, and the changes are applied to the device when the system is rebooted. This flag cannot be used withthe -T flag. Not all devices support the -P flag.
Changes the device's characteristics permanently in the Customized Devices object class without actually changing the device.This is useful for devices that cannot be made unavailable and cannot be changed while in the available state. The change ismade to the database, and the changes are applied to the device when the system is rebooted. This flag cannot be used withthe -T flag. Not all devices support the -P flag.
查看aio进程数
引用
# pstat -a | grep aio
20 a 1478 1 1478 0 0 1 posix_aioserver
21 a 1540 1 1540 0 0 1 aioserver
48 a 30c4 1 30c4 0 0 1 aioserver
50 a 3250 1 3250 0 0 1 aioserver
68 a 44be 1 44be 0 0 1 aioserver
75 a 4baa 1 4baa 0 0 1 aioserver
76 a 4ca6 1 4ca6 0 0 1 aioserver
80 a 50b6 1 50b6 0 0 1 aioserver
89 a 59bc 1 59bc 0 0 1 aioserver
125 a 7d28 1 7d28 0 0 1 aioserver
127 a 7f0c 1 7f0c 0 0 1 aioserver
20 a 1478 1 1478 0 0 1 posix_aioserver
21 a 1540 1 1540 0 0 1 aioserver
48 a 30c4 1 30c4 0 0 1 aioserver
50 a 3250 1 3250 0 0 1 aioserver
68 a 44be 1 44be 0 0 1 aioserver
75 a 4baa 1 4baa 0 0 1 aioserver
76 a 4ca6 1 4ca6 0 0 1 aioserver
80 a 50b6 1 50b6 0 0 1 aioserver
89 a 59bc 1 59bc 0 0 1 aioserver
125 a 7d28 1 7d28 0 0 1 aioserver
127 a 7f0c 1 7f0c 0 0 1 aioserver
查看目前系统异步io是否遇到瓶颈
引用
# iostat -A 1 1
System configuration: lcpu=1 drives=3 paths=0 vdisks=0
aio: avgc avfc maxg maif maxr avg-cpu: % user % sys % idle % iowait
0 0 33 0 4096 0.4 0.8 98.8 0.0
Disks: % tm_act Kbps tps Kb_read Kb_wrtn
hdisk1 0.0 0.0 0.0 0 0
hdisk0 0.0 0.0 0.0 0 0
cd0 0.0 0.0 0.0 0 0
System configuration: lcpu=1 drives=3 paths=0 vdisks=0
aio: avgc avfc maxg maif maxr avg-cpu: % user % sys % idle % iowait
0 0 33 0 4096 0.4 0.8 98.8 0.0
Disks: % tm_act Kbps tps Kb_read Kb_wrtn
hdisk1 0.0 0.0 0.0 0 0
hdisk0 0.0 0.0 0.0 0 0
cd0 0.0 0.0 0.0 0 0
下面的列表描述了用于监视 AIO 子系统的一些参数。
* avfc:这个参数用于报告在指定的时间间隔内每秒的平均快速路径请求计数。
* avgc:这个参数用于报告在指定的时间间隔内每秒的平均全局异步 I/O 请求。
* maxgc:这个参数用于报告从上一次获取这个值以来最大的全局异步 I/O 请求。
* maxfc:这个参数用于报告从上一次获取这个值以来快速路径请求计数的最大值。
* maxreqs:这个参数是允许的、异步 I/O 请求的最大值。
在我们的示例中,AIO 服务器不是系统瓶颈。
需要注意的是在AIX 6L中异步io会自动开启,maxreqsminservers、maxservers也会根据应用而自动调整,无须人工干预,当然也没有smitty aio这条命令了,呵呵
附:metalink的说明
Solution
AIX 5L supports asynchronous I/O (AIO) for database files created both on file system partitions and on raw devices.
AIO on raw devices is implemented fully into the AIX kernel, and does not require database processes to service the AIO requests.
When using AIO on file systems, the kernel database processes (aioserver) control each request from the time a request is taken off the queue to the time it is completed. The number of aioserver servers determines the number of AIO requests that can be processed in the system concurrently. So, it is important to tune the number of aioserver processes when using file systems to store Oracle Database data files.
Use one of the following commands to set the number of servers. This applies only when using
asynchronous I/O on file systems rather than raw devices:
smit aio
chdev -l aio0 -a maxservers=' m ' -a minservers='n'
Set the minimum value to the number of servers to be started when the system is started. Set the maximum value to the number of servers that can be started in response to a large number of concurrent requests. These parameters apply to file systems only. They do not apply to raw devices.
The default value for the minimum number of servers is 1. The default value for the maximum number of servers is 10. These values are usually too low to run Oracle Database on large systems with 4 CPUs or more, if you are not using kernelized AIO. Oracle recommends that you set the parameters to the values listed in the following table.
Parameter Values
=============
minservers
Oracle recommends an initial value equal to the number of CPUs on the system or 10, whichever is lower.
maxservers
Starting with AIX 5L version 5.2, this parameter counts the maximum number of AIO servers per CPU. On previous versions of AIX, it was a systemwide value. If you are using GPFS, then set maxservers to worker1threads divided by the number of CPUs. This is the optimal setting.
Increasing maxservers does not lead to improved I/O performance. If you are using JFS/JFS2, then set the initial value to 10 times the number of logical disks divided by the number of CPUs.
Monitor the actual number of aioservers started during a typical workload using the pstat or ps commands. If the actual number of active aioservers is equal to the maxservers, then increase the maxservers value.
maxreqs
Set the initial value to 4 times the number of logical disks multiplied by the queue depth. You can determine the queue depth by running the following command:
$ lsattr -E -l hdiskxx
Typically, the queue depth is 3.
If the value of the maxservers or maxreqs parameter is set too low, then the following warning messages are repeatedly displayed:
"Warning: lio_listio returned EAGAIN
Performance degradation may be seen."
You can avoid these errors by increasing the value of the maxservers parameter. To display the number of AIO servers running, enter the following commands as the root user:
# pstat -a | grep -c aios
# ps -k | grep aioserver
Check the number of active AIO servers periodically, and change the values of the minservers and maxservers parameters if required. The changes take place when the system is restarted.
发表评论
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记一次rsync在nfs环境下错误处理
2011-05-26 13:44 2402公司有一应用,即利用rsync开源工具从生产机拉归档日志至备份 ... -
浅谈AIX /var/adm/wtmp
2010-12-11 18:42 4969今天登陆系统时报如下错误 引用telnet (mcsvr) ... -
AIX和linux之间挂载nfs错误
2010-11-25 12:12 1858linux作为nfs服务器,其/etc/exports文件为 ... -
记一次存储不可读修复
2010-08-31 14:05 2136同事告诉我一AIX主机文件系统不可写 引用# touch ll ... -
记一次AIX平台存储脏块处理
2010-08-06 13:36 2517客户数据库出现问题,归档日志不可读,具体表现为 引用$ du ... -
AIX 配置vncserver
2010-06-08 09:40 8294我们安装数据库时,很多情况下客户现场并没有配置图形界面,这是就 ... -
vi替换文本中的^M
2010-04-16 13:27 2990工作中经常碰到^M结尾的文本,可以用以下方法替换 引用:%s/ ... -
AIX 挂载NFS错误nfsmnthelp: 1831-019之解决
2010-04-10 12:56 11721介绍解决方法之前,先简单说明系统环境,共涉及到4台主机。为了保 ... -
AIX 查看网卡是否做绑定
2010-04-08 11:49 5056可以通过lsattr命令查看网卡是否做过绑定,以下仅作记录 引 ... -
AIX查看rootvg是否做镜像
2010-04-08 11:22 2916因工作需要,仅作记录 AIX查看rootvg是否做镜像,只需要 ... -
AIX 使用lsof查看端口占用进程
2010-03-12 10:05 10751lsof功能很强大,这里主要介绍使用lsof查看端口占用进程, ... -
AIX 关闭ftp服务
2010-03-12 09:29 6393很多情况下,比如处于安全考虑,我们需要关闭ftp服务。在AIX ... -
AIX working with the LDR_CNTRL environment variable
2010-03-11 08:48 2441The LDR_CNTRL environment varia ... -
Aix 查看进程占用内存大小(按从大小排列)
2010-03-08 13:43 14783主要通过以下两条命令进行观察,单位为K RSS表示the am ... -
AIX 6L虚拟内存参数变化
2010-02-08 14:31 1971操作系统版本为: 引用P590_lpar1/>oslev ... -
AIX 查看HA脚本位置
2010-01-20 09:14 2805#smitty hacmp =>Initializati ... -
AIX 虚拟内存管理(VMM)优化
2010-01-14 16:17 2408AIX版本为 引用#oslevel -r 5300-04 查看 ... -
AIX 域名解析顺序
2010-01-07 15:55 2978AIX 主机IP地址的解析顺序依次是dns/bind,nis, ... -
AIX ruby调用openssl LoadError
2010-01-05 16:35 2450ruby调用openssl时报如下错误: 引用 # oslev ... -
AIX 平台ruby卸载
2010-01-05 16:27 1431ruby在AIX平台下默认安装路径如下,将以下文件删除即可 引 ...
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