Ramdisk
 

Hi,

I am using opennms on a 64 bit centos5 machine, its postgres installed separate file system, when i start opennms and postgres its load avrage goes to abmormal and mechine responce is too slow. and its iostats show 100%

Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda2 0.00 153.40 244.40 106.40 3131.20 2001.60 14.63 119.35 323.82 2.85 100.02

To double check it have setup a 16 GB ram disk and move the database data on it but still its var shows 100%

Have some body any idea how ramdisk is work or i am missing any thing, following is the ram disk configuration

#mkfs -q /dev/ram1 15728640
#mount /dev/ram1 /mnt/rd

# pwd
/var/lib
#mv pgsql /mnt/rd/
#ln -s /mnt/rd/pgsql ./


Thanks
Mudasar

You are going to lose your pgsql db if you mv it to RAM.
I'm using much simplier "mount -t tmpfs" (man mount), but does your /dev/ram1 is 16GB? How much memory do you have on that system and how large is your DB? I'm curious how bad can it be configured so that such huge HW resources won't let it work ^_^
In fact I thought /dev/ram* is not for that purpose.

Thanks,

This machine has 32Gb memory, yes i know data will be lost if i reboot the machine..... but i use it as the last possibility.
DB is around about 200MB.
When postgres is stopped var i/o utilization is 0%, as i start the postgres its i/o utilization goes to 100%, I am surprised that even i have move the complete postgres directory to ramdisk why var i/o utilization is 100%.


Mudasar