How to prevent varyonvg command to an already used VG

How to prevent varyonvg command to an already used VG

Post by shar » Sat, 07 Dec 2002 05:52:27



Hello to you all.
My problem is this.
I'm using 2 pSeries640 B80 with Clarion5300 FB storage machine.
I created 3 volume groups on the Clarion.
The first VG is for server 1 use only.
The second VG is for server 2 only.
the third is for both but not at the same time.
I'm not using HACMP (yet).
The problem is that I can't prevent both computers from issuing at the
same time the varyonvg command on the third VG.
The VG is not opened at boot time.
I have a script that runs at boot time and detremind which server is the
first to come up ,Then it issue the varyonvg command.
I noticed that if I run the varyonvg command from the second computer
when the VG is already in varyon state from the first server I can do
this with no problem.
Is there a way to issue a warning or somthing ?
is there a way to prevent this ?
Does the AIX knows how to protect the VG from been varyon at the same
time from 2 different computers ?

Thanks in advance
Lior

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How to prevent varyonvg command to an already used VG

Post by shar » Sat, 07 Dec 2002 05:56:13


!

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How to prevent varyonvg command to an already used VG

Post by Simon Marches » Sat, 07 Dec 2002 19:14:04



> Hello to you all.
> My problem is this.
> I'm using 2 pSeries640 B80 with Clarion5300 FB storage machine.
> I created 3 volume groups on the Clarion.
> The first VG is for server 1 use only.
> The second VG is for server 2 only.
> the third is for both but not at the same time.
> I'm not using HACMP (yet).
> The problem is that I can't prevent both computers from issuing at the
> same time the varyonvg command on the third VG.
> The VG is not opened at boot time.
> I have a script that runs at boot time and detremind which server is the
> first to come up ,Then it issue the varyonvg command.
> I noticed that if I run the varyonvg command from the second computer
> when the VG is already in varyon state from the first server I can do
> this with no problem.

It should not be possible to do this as AIX varyonvg command sets SCSI
reserves on the disks it accesses. So, if it can be done, what are the
disks? Clariion - do they support SCSI reserve? Best ask EMC.

- Show quoted text -

Quote:> Is there a way to issue a warning or somthing ?
> is there a way to prevent this ?
> Does the AIX knows how to protect the VG from been varyon at the same
> time from 2 different computers ?

 
 
 

How to prevent varyonvg command to an already used VG

Post by shar » Sat, 07 Dec 2002 22:18:23


Hi ,
The Clarion 5300 using fiber chanell technology to transport the data.
The physical disks resides in this particular machine are using SCSI
Ultra 160 technology.
I will call EMC first thing Monday morning and ask them about this but
it is really strange that you mentioned the SCSI reserve since I already
spoke to IBM tech support and they said that there is nothing to do
about this
there is no AIX protection to this issue.
Does it sound reasonable to you ?
Does IBM counting on the SCSI devices that I'm using ?
can you point me to some article about this SCSI disk reservation ?
Thanks in Advance
Lior

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How to prevent varyonvg command to an already used VG

Post by Simon Marches » Sun, 08 Dec 2002 21:25:02



> Hi ,
> The Clarion 5300 using fiber chanell technology to transport the data.

Yes, but the protocol used over the fibre is part of the SCSI-3 standard.

Quote:> The physical disks resides in this particular machine are using SCSI
> Ultra 160 technology.
> I will call EMC first thing Monday morning and ask them about this but
> it is really strange that you mentioned the SCSI reserve since I already
> spoke to IBM tech support and they said that there is nothing to do
> about this there is no AIX protection to this issue.

That is a strange response. I can confirm that varyonvg sets SCSI
reserve on hdisks. Lookup "varyonvg" on google and you will find the
varyonvg man page which describes reserves.

Quote:> Does it sound reasonable to you ?
> Does IBM counting on the SCSI devices that I'm using ?
> can you point me to some article about this SCSI disk reservation ?

One extra point may be if you are using some kind of multipath software
like EMC PowerPath with these disks. If so, can you do the test without it?
 
 
 

How to prevent varyonvg command to an already used VG

Post by shar » Sun, 08 Dec 2002 22:52:12


which responsible to "move" the disks on the EMC from
one service processor to another if there is a problem with one
of the SP's.
/dev/atf0 is the SP0 and SP1 parent device.
the hdiskX are managed by the Sp's so it might be the problem.
I will uninstall the ATF and check it out.
Thanks

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1. hacmp 4.4.1 and manual varyonvg of shared vg

hi all
Environemt:
AIX 4.3.3
HACMP/ES 4.4.1
Mutual takeover
Activity:Application/DB upgrade
I have struck in one situation where my public wants to do the
activity:
1.just down hacmp gracefully on one node(nodeA).HACMP will be up and
running on other node node(B).My question is that  whether the other
node nodeB will try to take over RG of node A or not.I think that not
as we have gracefully down HACMP on nodeA......what are ur
ideas.....am i right????
2.Then manually varyon shared vg belonging to RG of nodeA.Perform the
application upgrade activity.
3.In the mean time assign service ip of nodeA on another Risc server
which is not HACMP cluster.Allow the users to do thier live work on
that node.
4.When upgrade acivity is completed just take off the Live service IP
address from non hacmp node and then start HACMP on nodeA.

Any thing wrong in that procedure....any thing wrong with respect to
ARP cache!!!Note that no HWAT in env.

SASA

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