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ORA-27054 when using RMAN to NAS/NFS disks

Posted by John Hallas on March 4, 2008


When an NFS disk is mounted there are a set of requested mount attributes. It is perfectly possible for an NFS disk to mount with the correct actual attributes (rsize/wsize etc) even if these attributes are not explicitly listed in the original mount request. However, on some platforms Oracle does not check the “actual” attributes and can think, incorrectly, that the disk is not mounted properly. Some platforms include an auto-mount feature which auto mounts the NFS disks, again with correct attributes, but Oracle cannot determine the actual mount point and attributes of the auto-mounted disk/s. As the files look like NFS type then again ORA-27054 is thrown even though the disks are mounted correctly as Oracle cannot confirm the mount attributes.


Use correct mount options.


default rsize and wsize for NFS is 4096 Blocks

Do not use auto-mount. Touching a file on the auto-mounted fs from your RMAN script does not wor.

set event=”10298 trace name context forever, level 32″ in the spfile and restart the instance. The event will disable the NFS checks in 10gR2 but it will also have some side effects:

– It will generate some trace files which you can ignore Bug:4998064 ‘Ksfq 10298 Trace Enabled For Levels Other Than Bit Level 0x2’ (unpublished)
– It can have a side effect of disabling direct IO on RAC using regular files on NFS mounts

This information comes from Metalink note 356199.1. I thought it worth commenting on as we have been testing RMAN network backups recently and I kept hitting the same problems as we have a sys admin who likes to use automount.


2 Responses to “ORA-27054 when using RMAN to NAS/NFS disks”

  1. oviwan said


    Have you already used rman with Direct NFS (dnfs) on oracle 11g? I have several problem. for example with native nfs I can restore a database but with dnfs it doesn’t work (with same /etc/fstab or oranfstab). I get the following message in alert log:
    Direct NFS: warn could not mount /nfs/path on svr via dNFS


    • John Hallas said

      I cannot say that I have tried direct NFS but the error message seems to be connected with teh options uses to mount the NFS share

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