Re: Re: [linux-lvm] LVM & high system load

Re: Re: [linux-lvm] LVM & high system load

[S. Michael Denton]

Dominique.Larchey-Wendling@loria.fr wrote:
> Dominique LARCHEY-WENDLING wrote:
> 
> 
> > relatively poor IO perf. (my cpu is only PII 333) on LVM volumes. I
have
> > tested reiserfs and ext2fs and I only get about 2.5Mb/s with 100% CPU
> > load,
> > mostly system time.
> 
> More over, doing a CPU intensive task (like kernel comp.) (not involving
> LVM, the
> sources are not on a LV) cut the IO perf. of LVM fs by half.
> 
> So it seems that the LVM is eating a lot of CPU on my system and this is
> what is limiting fs perf.

I doubt it, I've got LVM0.9.1b7 on a 486 without any real load... even when
compiling the kernel.  I also have reiserfs on 2.2.19.	I noticed in your
previous post that you had 3 pv's on the same physical disk... that may be
contributing, depending on your PE layout on the PVs.  If not, it's
definitely silly :)

> DL
> 
> -- 
> Dominique Larchey
> LORIA, Nancy, France
> Tel. (Work) +33 (0) 3 83 59 20 13
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> 
> 

--------------------------------------------------------------------------
Scott Denton
smdenton@bellsouth.net
EFNet Handle: SteelWyng

Re: [linux-lvm] LVM & high system load

[Dominique LARCHEY-WENDLING]

> I doubt it, I've got LVM0.9.1b7 on a 486 without any real load... even when
> compiling the kernel.  I also have reiserfs on 2.2.19.  I noticed in your
> previous post that you had 3 pv's on the same physical disk... that may be
> contributing, depending on your PE layout on the PVs.  

The layout is linear ...

-----------------------------------------------------------------

[root@charlie larchey]# /usr/sbin/lvdisplay -v /dev/mmedia/music

--- Logical volume ---
LV Name                /dev/mmedia/music
VG Name                mmedia
LV Write Access        read/write
LV Status              available
LV #                   2
# open                 2
LV Size                9 GB
Current LE             2304
Allocated LE           2304
Allocation             next free
Read ahead sectors     120
Block device           58:1

   --- Distribution of logical volume on 1 physical volume  ---
   PV Name                  PE on PV     reads      writes
   /dev/hda5                2304         2129836    343926   

   --- logical volume i/o statistic ---
   2129836 reads  343926 writes

   --- Logical extents ---
   LE    PV                        PE     reads      writes
   00000 /dev/hda5                 00006  1025       1875     
   00001 /dev/hda5                 00007  1024       1024     
   00002 /dev/hda5                 00008  1024       1024     
   00003 /dev/hda5                 00009  1024       961      
   00004 /dev/hda5                 00010  1024       0        
.....   
   02298 /dev/hda5                 02304  2048       1024     
   02299 /dev/hda5                 02305  2048       1024     
   02300 /dev/hda5                 02306  2048       1024     
   02301 /dev/hda5                 02307  2048       1024     
   02302 /dev/hda5                 02308  2048       1024     
   02303 /dev/hda5                 02309  2048       1024     

--------------------------------------------------------

> If not, it's definitely silly :)

It is NOT SILLY ... see next post for performance issues

DL

-- 
Dominique Larchey
LORIA, Nancy, France
Tel. (Work) +33 (0) 3 83 59 20 13