Writing large files to NFS mount causes high backlog wait stats, high avg exe or task blocked for more than 120 seconds messages
Issue
- Slow system response times during database backups
- Processes hanging while using I/O over NFS
- Updating to 2.6.18-274.el5 (from 2.6.18-194.17.1.el5) causes very high CPU with NFS IO severely impacted
- WRITE exe time is 10 seconds with high backlog wait.
Environment
- Red Hat Enterprise Linux 5 (NFS client)
- Red Hat Enterprise Linux 6 (NFS client)
- Red Hat Enterprise Linux 7 (NFS client)
- Typically these NFS clients have lots of RAM. e.g. Greater than 50 GiB of RAM.
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