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Top Forums UNIX for Advanced & Expert Users How to reduce IOWAIT in linux Post 302126795 by porter on Friday 13th of July 2007 05:34:46 AM
Old 07-13-2007
Not knowing much about your machine here are a few thoughts.

1. Are you using the fastest disks you can, both rotational speed and transfer speed and can your disk controllers support the transfer rates?

2. Consider having a number of disks so binaries live on different disks to data. This will reduce the time spent waiting for seeks to occur.

3. In certain configurations, a RAID arrangement may speed up access to disks.

4, Are you using delayed writes?
 

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vxsplitlines(1M)														  vxsplitlines(1M)

NAME
vxsplitlines - show disks with conflicting configuration copies in a cluster SYNOPSIS
vxsplitlines [-g diskgroup] [-c daname] DESCRIPTION
If you import portions of a disk group on different systems, this can lead to conflicting configuration copies on the disks of the disk group. If the configuration information in a disk group is ambiguous, it may not be possible for Veritas Volume Manager to determine which config- uration copy is most up-to-date. (This is usually termed a serial split brain (SSB) condition when it occurs in a cluster.) You cannot import a disk group in this state unless you specify which disk's configuration copy to use. You can use the vxsplitlines command to see which disks in a disk group have conflicting configuration copies, and use this information together with your knowledge of the history of the disk groups' usage to determine which configuration copy is most valid. The output from vxsplitlines displays the vxdg commands that you can run to import the disk group using the available configuration copies. The -o selectcp option of the vxdg import command is used to select the configuration copy to use for the import. OPTIONS
-c daname Display the SSB IDs for each disk that are stored in the configuration copy on the disk specified by its disk access name. Note: Although the SSB IDs for some disks may match, this does not necessarily mean that those disks' configuration copies have recorded all the configuration changes. When viewed from some other configuration copies, the SSB IDs of the same disks may not match. -g diskgroup Specifies the disk group. If a disk group is not specified, the default disk group is used as determined from the rules on the vxdg(1M) manual page. EXAMPLES
Display the disks on each side of the split in the disk group newdg: vxsplitlines -g newdg Display the SSB IDs stored in the configuration copy on disk c2t4d0: vxsplitlines -g newdg -c c2t4d0 NOTES
The vxsplitlines is primarily intended to be used with private disk groups, but it also works with shared disk groups. The version number of the disk group must be 110 or greater. SEE ALSO
vxdg(1M) Veritas Volume Manager Administrator's Guide VxVM 5.0.31.1 24 Mar 2008 vxsplitlines(1M)
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