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Slow Performance for NFS Repository Mounted with Options: "noac" and "forcedirectio" (Doc ID 2734341.1)

Last updated on SEPTEMBER 08, 2022

Applies to:

Oracle VM - Version 3.4.5 and later
Solaris (SPARC) - Version 10 and later


OVM Sparc servers is experiencing performance issues on EMC VNX NFS storage.

Running a simple dd command on the mounted repository shows the performance degradation:

root@<Hostname>:/mnt# time dd if=/dev/zero of=/OVS/Repositories/<Repository ID>/1GB bs=1024000 count=1024
1024+0 records in
1024+0 records out
real 0m39.304s
user 0m0.004s
sys 0m2.091s

The degradation of performance is also seen only after a Reboot.
If the repository is unpresented and presented back to the server OR if a repository is presented on the fly the performance is better. 


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