RAM fs (like tmpfs) on hpux

[Eric Guerizec]

Hi

Can we use a memory based file system on HPUX like tmpfs on Solaris? I would like to test it on hpux 11.23.

Regards

[Simon Hargrave]

HPUX does not support the use of RAM disks, however there are a number of "hacks" you can do if you really must. See this thread for some references: -

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=35625

[Jdamian]

Hi Eric.

I think HP don't support RAM disks... but it is something I cannot understand because when booting HP-UX from Support CD-ROM for recovery tasks, an RAM disk is used as root file system.

[Eric Guerizec]

Thanks Simon & Oscar

yes, I remember that the feature was not supported but I was thinking it could be a new feature with 11.23 ;)

I'am going to read this discussion.

Eric

[Florian Heigl (new acc)]

There is a very well thought-out 3rd party product called ramdisk/ux.

I had a trial copy on 11.00, the performance was great and it even mirrors back to a physical lv.

in the comp.sys.hpux faq there is a procedure on how to generate a ramdisk:
DO NOT USE IT - it's for HP-UX 9.x :)
it works as far as creating a specified size disk in memory, but it does not de-allocate the RAM properly
at the newfs part You will wipe the OS out of memory, so You'll have a working ramdisk in memory but no more operation system to operate it.

;)

[Florian Heigl (new acc)]

To add up:

the closest You get with a stock HP-UX is the tmplog directive for mounting the filesystem (I think it requires OnlineJFS, though)

If You get a real requirement for this, You might want to look into real ram-based SSDs, the prices have dropped quite considerably over the last years, but of course they're still horribly expensive. :)

[Eric Guerizec]

I have just read the message. One thing to remember : it is not supported ;)

I just wanted to make a performance test.

Florian, you're right. There is a product called RamDisc Plus
http://www.jtlltd.com/dnlpls.html

The new release support Itanium/Itanium2 processors!

Regards

[Florian Heigl (new acc)]

Oups, yes I didn't think of looking if ia64 was supported, thanks for adding that.

[Ted Buis]

Check on limits on the size as there may be some for RAMDISK. The were working on removing some of those limits, but I don't know where they are with it. They have some real success with some customers.

[Geoff Wild]

Another tip:

Want /tmp to really be temporary?

Just vi /etc/rc.config.d/clean_tmps and set CLEAR_TMP=1

On next boot - /tmp will be empty!

# cat /etc/rc.config.d/clean_tmps
#!/sbin/sh
# @(#)B.11.11_LR
# List and/or clear temporary files
#
# LIST_TEMPS: Set to 1 to produce a listing of temporary files at startup.
#
# CLEAR_TMP: Set to 1 to remove all files from /tmp at startup.
#
LIST_TEMPS=1
CLEAR_TMP=0


Rgds...Geoff

[John Scheller]

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