From the warnquota man page:
warnquota checks the disk quota for each filesystem and mails a warning message
to those users who have reached their softlimit.
This however does not work for nfs based mounts using quotas. This was reported
by a customer.
The support for NFS is disabled in the warnquota code. To confirm this, I posted
a note to the forum on the quota sourceforge.net page and got the confirmation
that it is not supported over NFS and no plans exist currently to add support.
A change instead was made to the warnquota man page to make it clear that
warnquota works only for local filesystems.
Can engineering please change the man page to make it clear that the warnquota
utility only works for local filesystems.
This request was evaluated by Red Hat Product Management for
inclusion, but this component is not scheduled to be updated in
the current Red Hat Enterprise Linux release. If you would like
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Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
The warnquota(8) man page implied that "warnquota" checks the disk quota for all file systems, whereas it actually only checks local file systems. The man page has been clarified in this regard, and no longer contains misleading information.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.