Add ramdisk to AIX machines

[gdams]

Following issues with citgm being particularly slow, I am going to add a ramdisk to power8-aix-nodejs2.osuosl.org to see if this helps increase performance.

cc/ @mhdawson @gibfahn

[gibfahn]

So we're starting with power8-nodejs2.osuosl.org (a.k.a. test-osuosl-aix61-ppc64_be-2). If everything works okay we can try with the other test machine, power8-nodejs1.osuosl.org (a.k.a. test-osuosl-aix61-ppc64_be-3)

[gibfahn]

If we go ahead with this, we need to make sure we update the Ansible script (and temporarily the manual instructions).

[gdams]

okay so running citgm on the ramdisk was much quicker (less than 20 minutes)

[gdams]

Commands to add the ramdisk:

mkramdisk 4G
mkfs -V jfs2 /dev/ramdisk0 
mkdir -p /ramdisk0
mount -V jfs2 -o log=NULL /dev/ramdisk0 /ramdisk0
mkdir /ramdisk0/citgm
chown /ramdisk0/citgm iojs

[gdams]

From googling, this seems to be the easiest way to mount the ramdisk at startup: @edelsohn @mhdawson

echo 'ramdisk:2:once:/usr/local/bin/ramdisk/ramdisk.ksh >/dev/null 2>&1' \
  >/usr/local/bin/ramdisk/ramdisk.ksh

ramdisk.ksh

RAMDISK=`mkramdisk 5G`
mkdir /ramdisk0 >/dev/null 2>&1
DEVICE="/dev/ramdisk`echo $RAMDISK | awk -F'ramdisk' '{print $2}'`"
echo "yes" | mkfs -V jfs2 $DEVICE
mount -V jfs2 -o log=NULL $DEVICE /ramdisk0
mkdir /ramdisk0/citgm
chown iojs /ramdisk0/citgm

[mhdawson]

@gdams, ramdisk.ksh seems to say '5M" is that correct or should it be 5G ?

A pull request against the build repo, adding ramdisk.ksh and updates to the ansible scripts to make it run on startup would be the best way to review

[gdams]

Oh sorry, it looks like @gibfahn edited my comment, take the configuration from the above comment that mentions 4G

[gibfahn]

ramdisk.ksh seems to say '5M" is that correct or should it be 5G ?

I copied that verbatim from the linked website. I've changed that to 5G, but I have no idea if the rest of it is applicable.

[gdams]

I also added the same config to power8-aix-nodejs3.osuosl.org (a.k.a. test-osuosl-aix61-ppc64_be-1)