Red Hat Bugzilla – Bug 675058
iostat: bogus value appears when device is unmounted/mounted
Last modified: 2011-07-21 06:41:18 EDT
Description of problem: When a filesystem partition is unmounted or mounted while iostat -kn is running, iostat reports bogus values. Also if a filesystem partition is mounted while the command is running, iostat seems not be aware of it at all. Version-Release number of selected component (if applicable): sysstart-7.0.2-3.el5 How reproducible: Always Steps to Reproduce: 1. mount NFS share # mount nfs:/share /nfs 2. run iostat # iostat -kn 1 | grep nfs:/share 3. iostat will report correct value. nfs:/share 10912.00 0.00 0.00 0.00 10912.00 0.00 341.00 341.00 0.00 nfs:/share 10048.00 0.00 0.00 0.00 10048.00 0.00 314.00 314.00 0.00 nfs:/share 10784.00 0.00 0.00 0.00 10784.00 0.00 337.00 337.00 0.00 nfs:/share 8595.04 0.00 0.00 0.00 8595.04 0.00 268.60 268.60 0.00 nfs:/share 10666.67 0.00 0.00 0.00 10698.04 0.00 333.33 334.31 0.00 4. umount the NF share # umount /nfs 5. iostat keeps reporting values for non-existing mount point nfs:/share 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 nfs:/share 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 nfs:/share 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 nfs:/share 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6. re-mount the NFS share # mount nfs:/share /nfs 7. Now iostat reports correct value though the 1st value looks invalid nfs:/share 18014398509162156.00 0.00 0.00 0.00 18014398509172004.00 0.00 18446744073709543424.00 18446744073709543424.00 0.00 nfs:/share 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 nfs:/share 0.00 0.00 0.00 0.00 Actual results: iostat is not aware of unmounted filesysem partition; it's not aware of the filesystem partition mounted again; and it's not aware of any filesystem partition mounted while it's running. Expected results: iostat must be umount/mount aware. Additional info:
Add CC List
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. New Contents: In previous versions of the iostat utility, the number of NFS mount points was hard-coded. Consequently, various issues occurred while iostat was running and NFS mount points were mounted or unmounted; certain values in iostat reports overflowed and some mount points were not reported at all. With this update, a patch has been provided for iostat to properly recognize when an NFS mount point mounts or unmounts, fixing these issues. See also: 706095, 694767
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. http://rhn.redhat.com/errata/RHSA-2011-1005.html