Fun fact about OpenVMS 7.3-2 multipathing

Discovered this week that OpenVMS 7.3-2 apparently doesn't turn on its multipathing brain unless it has a second HBA installed, in Fabric mode (via wwidmgr), and zoned over both HBAs.  I imagine it's just a side effect of the multipathing logic pre-dating SANs with multiple paths to a single HBA, but it sure caused quite a bit of consternation when I was prepping to do SP failure testing on an EMC VNX and couldn't get paths to show.

Random AIX 5.3 Notes - expanding a logical volume

I've spent the past few days working on getting a PowerPath issue resolved on an AIX 5.3 box.  I rarely touch these things so my familiarity is abysmal making this much more difficult than it probably needs to be.  So I thought I'd just scribble down a few random things that I've worked through in hopes that it'll help someone else.


Expanding a logical volume without adding disks for those of us still stuck in the 90s (assumes it has already been expanded at the SAN level):


# Unmount, varyoff and export the volume group
bash-2.05b# umount /mountpoint
bash-2.05b# cfgmgr
bash-2.05b# varyoffvg thisvg
bash-2.05b# exportvg thisvg


# Deal with pv weirdness
bash-2.05b# chdev -l hdiskdevice# -a pv=clear
hdiskdevice# changed
bash-2.05b# chdev -l hdiskdevice# -a pv=yes
hdiskdevice# changed


# Recreate the volume group | -Y NA means don’t automatically rename the logical volumes
bash-2.05b# recreatevg -Y NA -y thisvg hdiskdevice#
0516-1434 varyonvg: Following physical volumes appear to be grown in size.
        Run chvg command to activate the new space.
        hdiskdevice#
thisvg
0516-1434 varyonvg: Following physical volumes appear to be grown in size.
        Run chvg command to activate the new space.
        hdiskdevice#


# check and grow vg - hello free PPs!
bash-2.05b# chvg -g thisvg
0516-1164 chvg: Volume group thisvg changed.  With given characteristics thisvg
        can include upto 7 physical volumes with 4064 physical partitions each.
bash-2.05b# lsvg thisvg | grep "FREE PPs" 
MAX LVs:            256                      FREE PPs:       856 (54784 megabytes)


# Take care of the filesystem - /fs is automatically added to the mountpoint when it’s recreated
bash-2.05b# chfs -m /mountpoint /fs/mountpoint
bash-2.05b# mount /mountpoint


# if needed, increase allowed LPs in LV
bash-2.05b# chlv -x 4686 thislv 


# Grow the filesystem, confirm the change
bash-2.05b# chfs -a size=+54784M /mountpoint
Filesystem size changed to 419299328
bash-2.05b# df -k /mountpoint
Filesystem    1024-blocks      Free %Used    Iused %Iused Mounted on
/dev/thislv   209649664  74832836   65%      228     1% /mountpoint

App-V - Running apps in compatibility mode

Fun fact - you can add App-V virtual drive paths to the compatibility mode registry key and have your virtualized apps run in compatibility mode.  Normally, the shortcuts for App-V apps all point to sfttray.exe, so if you try to set compatibility on the generated App-V shortcut, you'll actually be setting it on sfttray.exe for all App-V apps.

Just head over to HKLM/Software/Microsoft/Windows NT/CurrentVersion/AppCompatFlags/Layers.  Create a new REG_SZ where the name of the item is the virtualized path (for example, Q:\MyApp.000\MyApp.exe and the value is the compatibility mode (WINXPSP3 for example).

The downside of this (at least so far) is that when I set this to WinXP something trips in the App-V stack to now require admin privs.  If I could make that magically go away, this would be a good day.