log file parallel write

The log file parallel write Oracle metric indicates the process is waiting for blocks to be written to all online redo log members in one group. LGWR is typically the only process to see this wait event. It will wait until all blocks have been written to all members.

Recommendation:
NOLOGGING / UNRECOVERABLE operations may be possible for certain operations to reduce the overall rate of redo generation. Use of the /*+ APPEND */ SQL Hint should be used on all UPDATE/INSERT statements that have transient data.

Note:
• RAW devices can be faster file system files
• RAID5 is not a good candidate for redo log members
• Redo log members must be on high speed disks
• Redo log members should be on disks with little/no IO activity from other sources (including low activity from other sources against the same disk controller)