experimenting with dmraid - disk status

Sandra Escandor sescandor at evertz.com
Fri Jun 10 14:32:31 UTC 2011 

I'll try the setup over again, just to make sure I've got the whole
thing setup correctly. What I did previously was to:
1. Create the dmraid RAID array.
2. Activate all dmraid volumes by issuing "dmraid -ay"
3. Start dmeventd.
4. Run "dm_dso_reg_tool -r" to register the devices.
5. Run "dm_dso_reg_tool -m" to show me that the devices have been
registered with dmeventd (using libdmraid-events.so).

Regards,
Sandra

-----Original Message-----
From: ataraid-list-bounces at redhat.com
[mailto:ataraid-list-bounces at redhat.com] On Behalf Of Heinz Mauelshagen
Sent: Friday, June 10, 2011 9:47 AM
To: ATARAID (eg, Promise Fasttrak, Highpoint 370) related discussions
Subject: RE: experimenting with dmraid - disk status

On Fri, 2011-06-10 at 09:11 -0400, Sandra Escandor wrote:
> Hello Heinz,
> 
> Thanks for your reply. I took a bit of a break from this experiment,
but
> now I'm back. The output of "dm_dso_reg_tool -m" shows that the
devices
> have indeed been registered. But the metadata is not changed when one
of
> the disks becomes "disabled" (according to dmsetup status). The
metadata
> on the disks should reflect this with some sort of change in the
> metadata, right? Or am I wrong?

dmsetup (a developer level test tool) only shows _incore_ state, not
disk state of the isw metadata.

Use dmraid to show on disk metadata state.

Regards,
Heinz

> 
> Regards,
> Sandra
> 
> -----Original Message-----
> From: ataraid-list-bounces at redhat.com
> [mailto:ataraid-list-bounces at redhat.com] On Behalf Of Heinz
Mauelshagen
> Sent: Friday, May 13, 2011 11:35 AM
> To: ATARAID (eg, Promise Fasttrak, Highpoint 370) related discussions
> Subject: RE: experimenting with dmraid - disk status
> 
> 
> Hi Sandra,
> 
> your case described looks like the dmraid dmeventd isw plugin is not
> installed and if it is, the devies aren't being registered for event
> monitoring properly. Check with "dm_dso_reg_tool -m" if the devices
got
> registered properly which I assume is not the case.
> 
> Regards,
> Heinz
> 
> On Fri, 2011-05-13 at 09:00 -0400, Sandra Escandor wrote:
> > I'm not sure if my question was sent properly last time, so I'm
> > resending :) Is it true that if in the middle of a RAID i/o, one of
> the
> > disks fail, dmevent doesn't actually change the metadata at all? My
> > experiment procedure is listed below. Perhaps I did something wrong?
> > 
> > Thanks for clarifying,
> > Sandra
> > 
> > -----Original Message-----
> > From: Sandra Escandor 
> > Sent: Tuesday, May 03, 2011 1:46 PM
> > To: 'ATARAID (eg, Promise Fasttrak,Highpoint 370) related
discussions'
> > Subject: RE: experimenting with dmraid - disk status
> > 
> > Ok, I've set it up so that I transfer a large file onto the RAID,
and
> > then during the transfer, I pull out a member disk to simulate a
disk
> > failure. I would like to confirm if I should be seeing what I'm
> seeing:
> > 
> > -The output of "dmraid -n" shows disk[0].status: 0x53a for all of
the
> > disks, even the one pulled out. I expected dmeventd to change one of
> > them, since I'm doing I/O as you had mentioned. Is what I was
> expecting
> > incorrect?
> > -The output of "dmraid -n" shows
> isw_dev[0].vol.map[0].failed_disk_num:
> > 255. I expected this to be the number of the disk that I have
removed.
> > Is what I am expecting for this field incorrect?
> > 
> > I do see that dmsetup and dm_dso_reg_tool give the proper output (as
> > mentioned in the document "How to Guide: DMRAID Eventing - What To
> > Expect"), so that's good. So, does this mean that dmeventd doesn't
> > modify the metadata at all as what I had expected above?
> > 
> > Thanks,
> > Sandra
> > 
> > -----Original Message-----
> > From: ataraid-list-bounces at redhat.com
> > [mailto:ataraid-list-bounces at redhat.com] On Behalf Of Heinz
> Mauelshagen
> > Sent: Tuesday, May 03, 2011 8:46 AM
> > To: ATARAID (eg, Promise Fasttrak, Highpoint 370) related
discussions
> > Subject: RE: experimenting with dmraid - disk status
> > 
> > On Tue, 2011-05-03 at 07:58 -0400, Sandra Escandor wrote:
> > > So, if I understood what you have said correctly, then the
following
> > > would be true:
> > > 
> > > - When there is no I/O being performed on the RAID, and then one
of
> > the
> > > member disks becomes disconnected for some reason, then a dmeventd
> > event
> > > would not be generated.
> > 
> > Correct.
> > 
> > > - After a while, I/O does get performed on the RAID (with a member
> > disk
> > > disconnected), then that will be the time that a dmeventd event
gets
> > > generated.
> > 
> > Correct.
> > 
> > Any generated events are being based on io, not on _any_ other
events
> > such as unplugging a drive.
> > 
> > Heinz
> > 
> > > 
> > > Is that right?
> > > 
> > > -----Original Message-----
> > > From: ataraid-list-bounces at redhat.com
> > > [mailto:ataraid-list-bounces at redhat.com] On Behalf Of Heinz
> > Mauelshagen
> > > Sent: Monday, May 02, 2011 4:53 PM
> > > To: ATARAID (eg, Promise Fasttrak, Highpoint 370) related
> discussions
> > > Subject: RE: experimenting with dmraid - disk status
> > > 
> > > On Mon, 2011-05-02 at 15:19 -0400, Sandra Escandor wrote:
> > > > After I installed the dmeventd package, I notice the following:
> > > > (general setup: ICH10R controller, raid0+1, 4 member disks)
> > > > - When I pull out a drive, then run dm_dso_reg_tool -m, the
> section
> > > > "Error Events Recorded by Kernel" for the superset and two
subsets
> > are
> > > > still 0. Is this expected?
> > > 
> > > Unless you performed io on the set.
> > > 
> > > > - (Drive still physically disconnected) when I run dmraid -n,
the
> > > > metadata shows that the status of the disk that I pulled out
still
> > has
> > > > the same status as the other disks which are plugged in (i.e
> > > > disk[0].status: 0x53a is shown for all of the disks, even the
one
> > that
> > > > I pulled out).
> > > 
> > > Same as above.
> > > 
> > > Heinz
> > > 
> > > > 
> > > > The steps that I took to set up the device mapper raid event
> > > monitoring
> > > > are basically the same as the one found in: "How to Setup Device
> > > Mapper
> > > > Raid event Monitoring_0.74.pdf"
> > > > (http://sources.redhat.com/lvm2/wiki/DMRAID_Eventing)
> > > > EXCEPT: 
> > > > * I obtained the dmeventd package from the Ubuntu repository
> > > (Maverick)
> > > > * I didn't install the patch (since I'm using kernel 2.6.35)
> > > > * I changed the makefile of libdmraid-events so that it would
link
> > > with
> > > > the pthread library (i.e added -lpthread to the makefile).
> > > > 
> > > > Is there another package that I need to install, or have I not
set
> > > this
> > > > up properly?
> > > > 
> > > > Thanks for the clarifications,
> > > > Sandra
> > > > 
> > > > -----Original Message-----
> > > > From: Heinz Mauelshagen [mailto:heinzm at redhat.com] 
> > > > Sent: Friday, April 29, 2011 10:14 AM
> > > > To: Sandra Escandor
> > > > Subject: RE: experimenting with dmraid - disk status
> > > > 
> > > > On Fri, 2011-04-29 at 08:00 -0400, Sandra Escandor wrote:
> > > > > I forgot to mention my metadata type. Yes, I'm using Intel
> > software
> > > > raid
> > > > > (so it's in isw format). Where would I be able to get this
> plugin?
> > > > 
> > > > You should get them with any distros dmraid-events package.
> > > > 
> > > > Heinz
> > > > 
> > > > > 
> > > > > Thanks,
> > > > > Sandra
> > > > > 
> > > > > -----Original Message-----
> > > > > From: ataraid-list-bounces at redhat.com
> > > > > [mailto:ataraid-list-bounces at redhat.com] On Behalf Of Heinz
> > > > Mauelshagen
> > > > > Sent: Friday, April 29, 2011 3:58 AM
> > > > > To: ataraid-list at redhat.com
> > > > > Subject: Re: experimenting with dmraid - disk status
> > > > > 
> > > > > On Thu, 2011-04-28 at 09:30 -0400, Sandra Escandor wrote:
> > > > > > Hello,
> > > > > > 
> > > > > >  
> > > > > > 
> > > > > > I was doing a bit of experimenting with dmraid. What I have
> done
> > > is
> > > > to
> > > > > > create a raid0+1 array, and then physically pull one of the
> > disks
> > > > out.
> > > > > > I then use the command "dmraid -n" to look at the metadata
on
> > the
> > > > > > member disks. I notice that the member disk listed by the
> output
> > > > that
> > > > > > has the specific serial number of the disk that I pulled,
> whose
> > > > status
> > > > > > I expect to be different from the other disks listed, still
> has
> > > the
> > > > > > same status as the other still physically plugged in. (i.e
> > > > > > disk[0].status: 0x53a is shown for all of the disks, even
the
> > one
> > > > that
> > > > > > I pulled out). Is this normal?
> > > > > 
> > > > > Yes, unless it's isw format, where a plugin exists to update
the
> > > > > metadata.
> > > > > 
> > > > > Heinz
> > > > > 
> > > > > > 
> > > > > >  
> > > > > > 
> > > > > > The following is the output of "dmraid -V":
> > > > > > 
> > > > > > dmraid version: 1.0.0.rc16 (2009.09.16) shared
> > > > > > 
> > > > > > dmraid library version:  1.0.0.rc16 (2009.09.16) 
> > > > > > 
> > > > > > device-mapper version: 4.13.0
> > > > > > 
> > > > > >  
> > > > > > 
> > > > > > Thanks for clarifying,
> > > > > > 
> > > > > > Sandra 
> > > > > > 
> > > > > > 
> > > > > > _______________________________________________
> > > > > > Ataraid-list mailing list
> > > > > > Ataraid-list at redhat.com
> > > > > > https://www.redhat.com/mailman/listinfo/ataraid-list
> > > > > 
> > > > > 
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> > > > 
> > > > 
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