lvmkd

[Lai Nee Shyang_1]

Hi there,

May I know what does lvmkd does in a HP-UX 11.0 environment. Recently, my SAP on Oracle 8.0 is slowing down to a crawl. From some basic analysis, I found that one of the logical device is showing high response time (in terms of 1,000 ms) even though the lv is stripe 64K across 4 devices. I'm looking for all posibilities to improved the situation and one of them is decrasing the lvmkd nice value, but I'm not certain if it will help at all.

Thanks, I welcome any advice.

Lai
SIngapore Power Ltd.

[eran maor]

Hi

The lvmkd's are daemon processes that watch a queue. When a job
arrives in the queue an lvmkd launches the job as a process,
which is now managed by the kernel and is subject to the normal
priority and CPU constraints as other processes.

The following are the routines that call lvmkd:

* NAME: lv_check_pf_pvs
*
* FUNCTION:
* Look at all disks belonging to any volume group, if the device is
readable.
* assume it has come back to life and restart any I/O waiting for it.

* NAME: lv_startpv
*
* FUNCTION: Initiate all I/O pending for a given physical volume.
* Must not be called from within an interrupt
* service routine (biodone) to prevent recursion
* and reentry of the physical disk driver.

* NAME: lv_reschedule
*
* FUNCTION:
* Schedule pended logical operations. This function is called
when ever physical buffers have been released and there are
logical buffers waiting for physical buffers. This will
schedule as many pended logical buffers as possible given the
number of available physical buffers.
*
* NAME: lv_begin
*
* FUNCTION:
* Begin physical I/O operations.
* NAME: lv_initiate
* FUNCTION: Initiate all ready logical requests for a logical
volume.
*
* lv_resync_pfpv:
*
* For every PV in every VG, check for the LVM_PVNEEDSYNC flag
* and resync those PVs.