[Linux-cluster] Clustered VGs with many PVs slow to activate

[Janne Peltonen]

On Fri, Jun 29, 2007 at 12:49:07AM +0300, Janne Peltonen wrote:
> On Thu, Jun 28, 2007 at 11:49:11PM +0300, Janne Peltonen wrote:
> > that's it. They are all probably trying to activate the VG with 47 PV's,
> > and it seems to take ages.  It started an three-quarters of an hour ago,
> > and now I'm going to sleep (it's midnight here) and see if it'll be up
> > by tomorrow morning...
> 
> So I didn't go to sleep. The VG took /one and a half hours/ to activate.
> And operations such as pvdisplay /dev/sdau1 take ages (minutes and
> minutes), and the pvdisplay appears to hog cpu. Meanwhile:

Some data to give you the feel of things:

[jmmpelto at pcn1 ~]$ time sudo service clvmd restart
Deactivating VG mappi-primary:   0 logical volume(s) in volume group "mappi-primary" now active
                                                           [  OK  ]
Stopping clvm:                                             [  OK  ]
Starting clvmd:                                            [  OK  ]
Activating VGs:   2 logical volume(s) in volume group "main" now active
  78 logical volume(s) in volume group "mappi-primary" now active
                                                           [  OK  ]

real    4m40.448s
user    0m0.662s
sys     0m0.299s
[jmmpelto at pcn1 ~]$ time sudo vgextend mappi-primary $(for LETTER in {i..r}; do echo /dev/sd${LETTER}1; done)
Password:
  Volume group "mappi-primary" successfully extended

real    0m7.534s
user    0m0.197s
sys     0m0.112s
[jmmpelto at pcn1 ~]$ time sudo service clvmd restart
Deactivating VG mappi-primary:   0 logical volume(s) in volume group "mappi-primary" now active
                                                           [  OK  ]
Stopping clvm:                                             [  OK  ]
Starting clvmd:                                            [  OK  ]
Activating VGs:   2 logical volume(s) in volume group "main" now active
  78 logical volume(s) in volume group "mappi-primary" now active
                                                           [  OK  ]

real    43m17.340s
user    0m2.473s
sys     0m0.528s

Adding ten PV's increased the deactivation-activation-cycle time tenfold.
Whatever might be the reason for this.



--Janne
-- 
Janne Peltonen <janne.peltonen at helsinki.fi>