Use the commands in this section to control the write behavior of dirty blocks from the cache to the disk. These commands are available only on OES 2 Linux and later. For more information about using these commands, see Section 31.3, Configuring or Tuning Group I/O.
Specify the elapsed time to wait before group writes of journal blocks.
Replace seconds with the maximum number of seconds to elapse before forcing journal blocks to be written to the volume. The default value of seconds is 1.
Example
To group write journal blocks every 2 seconds, enter
nss Journal GroupWriteTime=2
Specify the elapsed time to wait before group writes of metadata blocks. Decreasing the metadata group write timer can help reduce the mount time for the volume after a crash.
Replace seconds with the maximum number of seconds to elapse before forcing metadata blocks to be written to the volume. The default value of seconds is 40.
Example
To group write metadata blocks every 30 seconds, enter
nss MetadataGroupWriteTime=30
Specify the elapsed time to wait before group writes of user data blocks. Decreasing the user data group write timer can help reduce the risk of data loss for a volume after a crash.
Replace seconds with the maximum number of seconds to elapse before forcing user data blocks to be written to the volume. The default value of seconds is 3.
Example
To group write user data blocks every 1 second, enter
nss UserDataGroupWriteTime=1
Specify the maximum number of metadata blocks that can be dirty before a group write is performed.
Replace blocks with the maximum number of metadata blocks that can be dirty before forcing them to be written to the volume. The default value of blocks is 20000.
Examples
To decrease the maximum number of dirty metadata blocks to 15,000 for the purpose of reducing the mount time, enter
nss MetadataGroupWriteLimit=15000
To increase the maximum number of dirty metadata blocks to 30,000 for the purpose of increasing the file system performance, enter
nss MetadataGroupWriteLimit=30000