[linux-lvm] Re: Daemon or Thread with 5 minute interval

[linux-lvm] Re: Daemon or Thread with 5 minute interval

[Bill Mair]

Howard Rifkin wrote:
>  So, my question is does anyone know of a
> kernel thread or daemon in the 2.4 kernel that wakes up every 5 minutes?

[kupdated] can cause massive CPU load if your kernel does not have the IDE 
chipset support for your system. I think it flushed any data in the HD
buffers to disk and if the chipset support isn't there, then the main CPU has
to do this using PIO.

--
Bill

Re: [linux-lvm] Re: Daemon or Thread with 5 minute interval

[Howard Rifkin]

We do have the right kernel support for our didsks. But, you do not need 
a lot of CPU activity to generate noise. Just enough to disrupt the 
cashe. Does kupdated run every 5 minutes? If so it could still be the 
culprit.

Thanks

Howard


Bill Mair wrote:
> Howard Rifkin wrote:
> 
>>  So, my question is does anyone know of a
>> kernel thread or daemon in the 2.4 kernel that wakes up every 5 minutes?
> 
> 
> [kupdated] can cause massive CPU load if your kernel does not have the 
> IDE chipset support for your system. I think it flushed any data in the HD
> buffers to disk and if the chipset support isn't there, then the main 
> CPU has
> to do this using PIO.
> 
> -- 
> Bill
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

[linux-lvm] Re: Daemon or Thread with 5 minute interval

[bill.mair]

Howard Rifkin wrote:

 >> So, my question is does anyone know of a
 >> kernel thread or daemon in the 2.4 kernel that wakes up every 5 minutes?
 >
 >[kupdated] can cause massive CPU load if your kernel does not have the IDE 
 >chipset support for your system. I think it flushed any data in the HD
 >buffers to disk and if the chipset support isn't there, then the main CPU has
 >to do this using PIO.
 >
 >--
 >Bill


** In addition to my post I might add that kswapd and bdflushd also deal with
IDE drives.

**  Correcting my initial reply, kupdated deals with "journal" flushing to the
HD, which may also be relevant on your cluster.

--
Bill

[linux-lvm] Re: Daemon or Thread with 5 minute interval

[Bill Mair]

Howard Rifkin wrote:
> 
> We do have the right kernel support for our didsks. But, you do not need 
> a lot of CPU activity to generate noise. Just enough to disrupt the 
> cashe. Does kupdated run every 5 minutes? If so it could still be the 
> culprit.

kupdated - journal update
kswapd - swapper
bdflush - flush IO

All/any of them could cause problems fir what you are doing, but I don't think
LVM is your problem.

--
Bill