Sign up. By signing in, you agree to our Terms of Use and Privacy Policy. Already have an account? Sign in. By signing up, you agree to our Terms of Use and Privacy Policy. Enter the email address associated with your account. We'll send a magic link to your inbox. Email Address. All Sign in options. When you define a striped logical volume, you must specify the items listed in the following table.
Performance gains from effective use of the LVM can vary greatly, depending on the LVM you use and the characteristics of the workload. For DSS workloads, you can see substantial improvement. For OLTP-type or mixed workloads, you can expect significant performance gains. Address the following considerations when deciding whether or not to use journaled file systems or raw logical volumes:. File systems are continually being improved, as are various file system implementations.
Different vendors implement the file system layer in different ways to capitalize on the strengths of different disks. This makes it difficult to compare file systems across platforms. The introduction of more powerful LVM interfaces substantially reduces the tasks of configuring and backing up logical disks based on raw logical volumes. If you use a journaled file system, then it is easier to manage and maintain database files than if you use raw devices.
In earlier versions of AIX, file systems supported only buffered read and write and added extra contention because of imperfect inode locking.
File System Options. The following table lists file systems available on AIX and the recommended setting. This delivers logging performance within a few percentage points of the performance of a raw device.
Therefore, the Oracle home directory and data files had to be placed in separate file systems for optimal performance. The Oracle home directory was placed on a file system mounted with default options, with the data files and logs on file systems mounted using the dio or cio options. As mentioned earlier, you should still place Oracle Database logs on a separate JFS2 file system for optimal performance. If you are using GPFS, then you can use the same file system for all purposes.
This includes using it for the Oracle home directory and for storing data files and logs. To move from a journaled file system to raw devices without having to manually reload all the data, perform the following steps as the root user:.
Create a raw device preferably, in a BigVG using the new raw logical volume device type -T O , which enables putting the first Oracle block at offset zero for optimal performance:. Use dd to convert and copy the contents of the JFS file to the new raw device as follows:. The first Oracle block on a raw logical volume is not necessarily at offset zero.
However, the first Oracle block on a file system is always at offset zero. When you have determined the offset, you can copy over data from a raw logical volume to a file system using the dd command and skipping the offset. The following example assumes an offset of bytes:. You can instruct Oracle Database to use a number of blocks smaller than the maximum capacity of a raw logical volume. If you do this, then you must add a count clause to ensure that only data that contains Oracle blocks is copied.
The following example assumes an offset of bytes, an Oracle block size of 8 KB, and blocks:. 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. The man pages for more information about the smit aio and chdev commands.
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 Oracle recommends that you set the parameters to the values listed in the following table.
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. If the value of the maxservers or maxreqs parameter is set too low, then the following warning messages are repeatedly displayed:. 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:. 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. Generally, you do not adjust the parameters in the preceding table.
However, on large workloads, the database writer may become a bottleneck. As a general rule, do not increase the number of database writer processes above one for each pair of CPUs in the system or partition. Dima Shcherbakov Dima Shcherbakov 66 3 3 bronze badges.
Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Helping communities build their own LTE networks. Podcast Making Agile work for data science. Newsletters may contain advertising. You can unsubscribe at any time. One of my file size when reached to 1Gb it logged out an error saying exceed 1Gb.
Is there any way I can tune the settings in the env? Thank you for the response. When running the ulimit command make sure you are logged in as the user who you made the change for. I have a question, related to the same subject. If so how? The only way I can think of is that you backup your filesystem and then remove it and re-create using large file enabled.
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