Disk Images Seems to be Automatically Unmounted?

this quite unusual case. quite simply; i'm using script mount disk-images @ start-up, triggered launchdaemon.

now, far can tell these images launch expected, when go looking them aren't mounted @ (they aren't attached) , can't life of me figure out why.

i'm going try extract relevant parts of shell script only, keep short i'll skipping of error-checks have i'm happy they're working expected anyway.

variable imagefile path disk-image (sparse bundles in case) , mountpoint folder want attach image to.

code:

# attach image-file  disks=`hdiutil attach -drivekey system-image=yes -nomount "$imagefile"`    # ad-hoc function lets disk identifier in spite of   # variable scoping issues due use of pipe  fngetdisk() {  	echo "$1" | while read identifier type name  	do  		if [ "apple_hfs" = "$type" ];  			echo $identifier  			break  		fi  	done  }    # find hfs volume mount  disk=$(fngetdisk "$disks")    # store permissions mount point  eval `stat -s "$mountpoint"`  owner="$st_uid:$st_gid"  perms="$st_mode"    # mount ram disk target mount point  mount -t hfs -o union,nobrowse,noatime $disk "$mountpoint"    # restore permissions mount point  chown $owner "$mountpoint"  chmod $perms "$mountpoint"

now, have error tests , echo statements every major part, appears working , console shows nothing success messages, yet 2 of 3 images i'm mounting aren't there after starting up. i've been unable determine why third image attached first 2 not.

in specific case i'm using disk images replace commonly accessed folders, in order avoid writing ssd (the disk images on volume). specific folders i'm switching out are:
/private/tmp (using ram disk)
/var/run (another ram disk)
/var/db (persistent disk image)
/var/folders (persistent disk image)
/var/log (persistent disk image)

now, 2 ram disks work fine, i've omitted part code. however, /var/db , /var/folders, despite appearing mount, unmounted time i've logged in.

particularly unusual /var/log getting disk identifier of disk14, despite appearing last in log, while /var/db , /var/folders getting disk15 , disk16 respectively. however, time i've finished logging in these 2 identifiers taken 2 core storage (encrypted) volumes. seems suggest /var/db , /var/folders somehow aren't mounting, yet not providing meaningful error (seems unlikely) or they're being unmounted on.

if run script manually mount expected, weird going on during startup.

 

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