Re: linux distro for better pg performance

>I am searching for best pg distro to run pg (7.4.1).
>  
>
This is generally based upon opinion.  Honestly though, your kernel 
version is more important for performance than the distro.  Personally I 
use gentoo, love gentoo, and would recommend very few other distros 
(Slackware) for servers.  RedHat and others seem to include 
kitchensinkd, when it's not needed.

>At the moment I am using RedHat AS 3.0, but I think it have some
>performance problems (I am not sure).
>My configuration:
>P4 2.8 GHz
>1 GB RAM
>120 GB IDE 7200 disk.
>  
>
Your IDE drive is the biggest hardward bottleneck here.  RPM's and bus 
transfers are slower than SCSI or SATA.

>Kernel version 2.4.21-4.EL (it is the installation vesrion for rh 3.0) .
>  
>
Jump to 2.6, it's much better for performance related issues, in my 
experience.

>My problems:
>
>If I run some query with many reads, I see a massive disk transfer :
>procs                      memory      swap          io
>system         cpu
> r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy
>id wa
> 0  0      0 261724   3252 670748    0    0     0     4  105    19  0  0
>100  0
> 0  0      0 261724   3252 670748    0    0     0     0  101    11  0  0
>100  0
> 0  0      0 261724   3260 670748    0    0     0     4  104    19  0  0
>100  0
> 0  1      0 259684   3268 674112    0    0   964     7  131    57  0  0
>95  4
> 1  0      0 119408   3288 808540    0    0 27960     0  572   630 13 14
>24 49
> 1  1      0  15896   3292 914436    0    0  7984 44744  531   275 11 18
>24 47
> 0  2      0  16292   3296 924996    0    0  4145  6413  384   176  2
>5  0 92
> 0  1      0  19928   3316 928844    0    0 11805 13335  497   388  5
>9  5 81
> 0  3      0  19124   3296 924452    0    0  3153 19164  287   295  5 11
>16 68
> 0  1      0  15956   3304 932984    0    0   536  6812  366   123  4
>6  3 87
> 0  2      0  24956   3300 921416    0    0  1931 22936
>
>And if I run top, I see a big iowait % (some times 70-80) and very low
>user % (10-15).
>  
>
again, this is your harddrive, and the kernel can play into that.

>I readet many docs about this problem, but do not find any solution.
>
>My question:
>
>If some one is using RH 3.0, pls post some result or suggestions for it
>performance with pg .
>
>What is the best linux distro for pg?
>  
>
There's no best, just personal preference.

>Can I get better performance by using 15K SCSI disk ?
>  
>
Absolutely

>Or it will be better to have more RAM (2 or 3 GB) ?
>  
>
Better to have a fast drive, but more ram can be helpful.

>regards,
>ivan.
>
>  
>
HTH,

Gavin