topic performance in Operating System - HP-UX

performance

Yair Goldel — Mon, 26 May 2003 06:46:14 GMT

I run process from one file system and the logs are written in separate file system
could be that the performance are lower then situation that the process will write the logs in the same file system ?
Does it care ?

Re: performance

Michael Tully — Mon, 26 May 2003 06:52:33 GMT

It will depend entirely upon whether both of the filesystems are on the same disk, how big the writes to disk are, what type of disks you have .... generally speaking if they are on a separate physical disk, the performance should be better. You can check easily enough using:
e.g.
# lvdisplay -v /dev/myvg/mylvol (for each one, this will display the same or different disks.
More information would be needed to assist more, type of process, database etc.

Regards
Michael
"When I have trouble spelling, it's called fat finger syndrome"

Re: performance

steven Burgess_2 — Mon, 26 May 2003 07:01:26 GMT

Hi

Do your filesystems reside on the same disk ?

Check with

lvdisplay -v /dev/vg#/lvol# | more

Have a look at the I/O on the disks with

sar -d 2 10

This will give you

08:59:05 device %busy avque r+w/s blks/s avwait avserv
08:59:07 c1t2d0 13.86 0.50 18 170 5.13 11.23

Have a look at the man pages for sar for a further description

Also have a think abouth wether your disks are internal or external to the server. Are any of them fibre connected. Are your filesystems striped across disks. There are numerous things to think about

HTH

Steve

Re: performance

Sunil Sharma_1 — Mon, 26 May 2003 07:43:51 GMT

Infact it's depends on how your application dealing with logs but in most of the cases it increase performence by keeping executable and log destinataion in different disk
Sunil

Re: performance

T G Manikandan — Mon, 26 May 2003 07:50:15 GMT

It depends on the type of application.

But to categorize the reasons why the logs are written to seperate file system

1.Normally in unix /var takes care of all the auditing and accounting.
All the logs are kept here so that the administration becomes easier so that they are not distributed on all file systems.

2.It could also be due to performance like take an example of Oracle database.

You have the redo log files which can cause more I/O and performance bottleneck.
Thus by distributing files across different file systems the I/O is reduced and thus improvement in performance.

Revert

Re: performance

Leif Halvarsson_2 — Mon, 26 May 2003 07:52:26 GMT

Hi,
It should not decrase performance, if it increases performance depends on how I/O intensive the application is but an general rule with I/O intensive applications is (if possible) to distribute the I/O across several disks.