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

[Christopher Barry]

On Fri, 2007-06-29 at 10:35 +0300, Janne Peltonen wrote:
> There seems to be great variation in the cycle time in different SAN
> load conditions:
> 
> On Fri, Jun 29, 2007 at 10:21:42AM +0300, Janne Peltonen wrote:
> > [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
> 
> (added and reduced 10 PV's) (and the activity on the SAN on other nodes
> decreased)
> 
> [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    1m54.891s
> user    0m0.672s
> sys     0m0.324s
> [jmmpelto at pcn1 ~]$ time sudo service clvmd restart
> Password:
> 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    2m3.736s
> user    0m0.660s
> sys     0m0.321s
> 
> 
> --Janne


What's interesting to me here is the huge difference in real vs. user or
sys time. It appears to spend most of the time waiting around.

Can you trace the process to see what it's doing and where it sits and
waits?



-- 
Regards,
-C