Bug 484439 - iostat -n enhancement not report NFS client stats correctly
iostat -n enhancement not report NFS client stats correctly
Status: CLOSED ERRATA
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: sysstat (Show other bugs)
5.3
All Linux
urgent Severity medium
: rc
: 5.4
Assigned To: Ivana Varekova
BaseOS QE
: OracleCert, ZStream
Depends On:
Blocks: 609991
  Show dependency treegraph
 
Reported: 2009-02-06 14:39 EST by Jeffrey Needham
Modified: 2011-07-21 06:40 EDT (History)
8 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Previously, the "iostat -n" command used invalid data to create statistics for read and write operations. With this update, the data source for these statistics has been fixed, and the iostat utility now returns correct information.
Story Points: ---
Clone Of:
Environment:
Last Closed: 2011-07-21 06:40:14 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
CRM:
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---


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Description Jeffrey Needham 2009-02-06 14:39:55 EST
Description of problem:
iostat -n shows exactly the same values for rops and wops 

Version-Release number of selected component (if applicable):
7.0.2-3

How reproducible:
iostat -kxn 2 (with NFS volumes mounted)

Steps to Reproduce:
1. mount an NFS volume
2. cp a file from this volume to local storage
3. iostat -kxn 2
  
Actual results:
Device:                   rkB_nor/s    wkB_nor/s    rkB_dir/s    wkB_dir/s    rkB_svr/s    wkB_svr/s    rops/s    wops/s
F3040:/vol/vol0                0.00         0.00         0.00         0.00         0.00         0.00   5627.00   5627.00
F3040:/vol/ed              20018.00         0.00         0.00         0.00     19920.00         0.00   5627.00   5627.00



Expected results:
Device:                   rkB_nor/s    wkB_nor/s    rkB_dir/s    wkB_dir/s    rkB_svr/s    wkB_svr/s      op/s    rops/s    wops/s
F3040:/vol/vol0                0.00         0.00         0.00         0.00         0.00         0.00   7594.00      0.00      0.00
F3040:/vol/ed              26986.00         0.00         0.00         0.00     26928.00         0.00   7594.00    841.50      0.00




Additional info:
Although my expected results came from a prototype version I had (where op/s was dropped in the production version), it seems like ops/s is being used instead of rops and wops; only a guess, though.

F3040 is a Netapp 3040
mount arguments:
rw,hard,nointrf,vers=3 rsize=32768,wsize=32768,proto=udp
Comment 1 Ivana Varekova 2009-04-15 04:46:46 EDT
Please could you attach here the output of:
cat /proc/self/mountstats  | grep xprt
for me it seems iostat is ok - but I need this data.
Comment 2 Jeffrey Needham 2009-06-24 13:49:45 EDT
So, I retested it with a simple copy from the mount to a local mount:

old version (a prototype I have; never released with 5.3)

Device:                   rkB_nor/s    wkB_nor/s    rkB_dir/s    wkB_dir/s    rkB_svr/s    wkB_svr/s      op/s    rops/s    wops/s
F960:/vol/vol0/home            0.00         0.00         0.00         0.00         0.00         0.00      0.00      0.00      0.00
F960:/vol/amd                  0.00         0.00         0.00         0.00         0.00         0.00      0.00      0.00      0.00
F3040:/vol/vol0                0.00         0.00         0.00         0.00         0.00         0.00   8005.50      0.00      0.00
F3040:/vol/ed              28482.00         0.00         0.00         0.00     28320.00         0.00   8005.50    885.00      0.00

RHEL5.3 production version
Device:                   rkB_nor/s    wkB_nor/s    rkB_dir/s    wkB_dir/s    rkB_svr/s    wkB_svr/s    rops/s    wops/s
F960:/vol/vol0/home            0.00         0.00         0.00         0.00         0.00         0.00      0.00      0.00
F960:/vol/amd                  0.00         0.00         0.00         0.00         0.00         0.00      0.00      0.00
F3040:/vol/vol0                0.00         0.00         0.00         0.00         0.00         0.00   9186.50   9186.50
F3040:/vol/ed              36682.00         0.00         0.00         0.00       482.00         0.00   9186.50   9186.50



        xprt:   tcp 1013 0 8 3 69 39 39 0 39 0
        xprt:   tcp 1013 0 8 3 69 39 39 0 39 0
        xprt:   tcp 891 0 8 3 43 192645 192645 0 325447 0
        xprt:   tcp 891 0 8 3 43 192645 192645 0 325447 0

During a copy only (i.e. no writes to the Netapp), there should be 0 wops and in this case, they are identical (implying that rops and wops are reading the same value and the wrong value). My guess is that rops and wops are being mapped to ops. If you had collapsed rops and ops together, then 91xx would be the right value.  However, wops should remain at zero. I would really like this fixed for 5.3 as some customers would like to use this feature (Yahoo, Shopzilla, Edmunds).
Comment 3 Ivana Varekova 2009-06-26 05:08:55 EDT
Hello, 
yes in this case there is used wrong value - this problem is fixed in the upstream version , here could be used the same fix.
Comment 4 RHEL Product and Program Management 2009-08-22 18:38:54 EDT
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
this request to be reviewed for the next minor release, ask your
support representative to set the next rhel-x.y flag to "?".
Comment 5 RHEL Product and Program Management 2009-11-06 14:27:15 EST
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
this request to be reviewed for the next minor release, ask your
support representative to set the next rhel-x.y flag to "?".
Comment 6 Greg Bradner 2009-12-01 18:45:35 EST
I really need this fixed now in version 5.3.  What is needed to make that happen?
Comment 17 Tomas Capek 2011-06-29 04:27:32 EDT
    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:
Previously, the "iostat -n" command used invalid data to create statistics for read and write operations. With this update, the data source for these statistics has been fixed, and the iostat utility now returns correct information.
Comment 18 errata-xmlrpc 2011-07-21 06:40:14 EDT
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

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