topic Using Memory to store Data in Operating System - HP-UX

Using Memory to store Data

George Nikoloudis_1 — Mon, 17 Dec 2001 19:08:53 GMT

Hello
I would like to ask:
in old days there was a function called RAMDRIVE where it was able to create a virtual drive in memory and access it.
Now I have an oracle with and I runn queries that they are using the TEMP tablespace/datafile. Is it possible to create a RAMDRIVE and mount the TEMP there?

Re: Using Memory to store Data

Sridhar Bhaskarla — Mon, 17 Dec 2001 20:05:42 GMT

Hi George,

I never tried but have been looking at this website since long time to see if I can try it instead of unsupported RAM disk by HP.

http://www.jtlltd.com/ramdsk.html

They sell a product to store data to RAM instead to hard disk drive.

If you have OnlineJFS you can also configure a file system with these options to make it like a RAMDisk.

mount /dev/vgxx/lvxx -o tmplog,mincache=tmpcache,convosync=delay
/mount_point

There is an unsupported way of adding a ramdisk. You need to add "ram" driver to your system file.

#/usr/lbin/sysadm/system_prep -s /stand/system
#kmsystem -c y -S system ram
#mk_kernel -o /stand/vmunix
#kmupdate
#shutdown -r now

Once the system is back up you need to create char and block devices for the ram disk.

mknod /dev/rRAM c 9 minor_number
mknod /dev/RAM b 9 minor_number
newfs -F vxfs /dev/rRAM
mkdir -p /RAMDISK
mount /dev/RAM /RAMDISK

Check out /usr/conf/sio/ram.h for more information on formatting the minor number.

-Sri

Re: Using Memory to store Data

George Nikoloudis_1 — Mon, 17 Dec 2001 20:26:47 GMT

Thanks a lot
One thing the unsupported verion of RAM Drive is it "recommended"?

Re: Using Memory to store Data

Sridhar Bhaskarla — Mon, 17 Dec 2001 20:40:13 GMT

Recommended?. It depends. The question comes from the fact that they are not to be used as stable storage as the data will not be preserved after reboot. They are best used for temporary file systems. I used it for oracle redo logs before but not using anymore now.And there are good "solid state" disks that can play like Ramdisks.

-Sri

Re: Using Memory to store Data

Patrick Wallek — Mon, 17 Dec 2001 20:43:04 GMT

Also, be aware that if you do use HP's "unsupported" method for creating a RAM drive, and something happens that kills your system and you need support, you more than likely won't get it.

"Unsupported" is use at your own risk, we're not responsible if you kill your system.

Re: Using Memory to store Data

John Scheller — Tue, 13 Feb 2007 21:48:58 GMT

The link posted above that contains the jtlltd.com domain is a dead link.
Here is the updated link.

http://www.ramdisc.com/ramdsk.html

Best Regards,
John