Bug 143390

Summary: iostat is unable to display device-mapper devices
Product: Red Hat Enterprise Linux 4 Reporter: Milan Kerslager <milan.kerslager>
Component: kernelAssignee: Alasdair Kergon <agk>
Status: CLOSED DUPLICATE QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.0CC: davej, jturner
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OS: Linux   
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Last Closed: 2005-11-16 16:28:52 UTC Type: ---
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Description Flags
/proc/diskstats none

Description Milan Kerslager 2004-12-20 10:42:20 UTC 
I have RAID-1 and datastorage on LVM2 (converted from LVM1 format). When using
"iostat", I'm able to see IO statistic for md0, md1, every hd[a-z] but not whole
LVM evn there is active and mounted LV on it. When trying to monitor only LVM
device, there is zero activity even there is /sys/block/dm-0 (with zeroes).

I'm able to see strange values for md0 and md1 too. md0 has only 2/3 of hda and
hdc (even they are dedicated for RAID-1 [md0 and md1]):

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda               1,33         0,00        15,95          0         48
hdc               1,33         0,00        15,95          0         48
md0               1,33         0,00        10,63          0         32
md1               0,00         0,00         0,00          0          0

Expected result: Ability to monitor IO in systemon all devices (RHEL4b2).
Comment 1 Charlie Bennett 2004-12-20 18:01:14 UTC 
hi - can you attach a copy of your /proc/diskstats?

Thanks
ccb
Comment 2 Milan Kerslager 2004-12-20 18:14:37 UTC 
Created attachment 108913 [details]
/proc/diskstats
Comment 3 Jay Turner 2005-01-14 14:37:32 UTC 
Back to assigned.
Comment 4 Charlie Bennett 2005-02-01 20:45:56 UTC 
The kernel does not report partition information for lvm devices in
/proc/diskstats.  Sysstat cannot report information it doesn't have.

I'll push this to the attention of the kernel group.
Comment 5 Alasdair Kergon 2005-11-16 16:28:52 UTC 

*** This bug has been marked as a duplicate of 168483 ***