Bug 22909

Summary: Vinum RAID5 degraded write not consistency
Product: Base System Reporter: rexluo <rexluo>
Component: kernAssignee: Greg Lehey <grog>
Status: Closed FIXED    
Severity: Affects Only Me    
Priority: Normal    
Version: Unspecified   
Hardware: Any   
OS: Any   

Description rexluo 2000-11-17 07:40:10 UTC

  If you copy one file(over 10Mb is better) to several copies at the 
same time(over 10 is better) on vinum raid5 drive in degraded mode(my 
configuration is 4 disks orignally, now degraded mode is 3 disks), them 
compare each copies with the original file. You will find some files are
different, and differences are not only one or two bytes. If you format
drive, and repeat again, number of wrong files and places are different.
That means the symptom are random case.

  If you copy and compare sequentially, everything is fine. If you do
the test during normal condition(4 disks from configuration), everything
is ok too. 


  My machine is Celeron 500 with 64M ram, my test script is like

#!/bin/sh
exec cp $1 1&
exec cp $1 2&
..
..
..

then you can compare the original file with 1, 2, 3, ....
(cmp file 1)

How-To-Repeat: 
Run the vinum raid5 less 1 disk than your configuration.
for example: configuration is 4 disk, you stop one sd,

write a script like
#!/bin/sh
exec cp $1 1&
exec cp $1 2&
...
...

copy more than 10 copies is better, and file size more than 10 Mb
is easier to hit.

cmp $1 1
cmp $1 2
..
..
..


the symptom is 
different file xxxx pace xxxxx
Comment 1 Søren Schmidt freebsd_committer freebsd_triage 2001-05-30 09:23:46 UTC
Responsible Changed
From-To: freebsd-bugs->grog

Vinum is groggy's baby.
Comment 2 Greg Lehey freebsd_committer freebsd_triage 2001-05-30 10:08:01 UTC
State Changed
From-To: open->closed

Problem has been fixed.