Hi,
I have created the lun of 15gb and assigned to aix,but now I want to expand the size of lun 15gb to 30gb,
I am having following queries.
1)wheather i have to umount that partition on aix side before increasing the size of lun on storage side or directly I can increase directly size of lun storage side
2)wheather i have use any other command along with extendvg
You can do so with certain SAN subsystems, but not all. IIRC DS8xxx models can do that but (older?) DS4xxx models can't.
No LUN is "mounted", because a LUN is neither a FS nor does it resemble one. A LUN is analogous to a (physical) disk. Physical disks (PVs) are merged into volume groups (VGs) on which logical volumes (LVs) are created on which in turn filesystems (FSs) could be created. Only these filesystems are mounted, not the other logical entities.
(Sorry for maybe being overly exact, i have seen people not being able to grasp the differences mentioned above and for that reason not being able to use LVM correctly.)
If you mean to "varyoff" the VG during the change: no, this is not necessary. Either the SAN subsystem can do dynamic changes of LUNs, then you can do it during uptimes or the SAN subsystem can't do that, then you will have to create a new (bigger) LUN, add it to the VG (extendvg) , move the LVs to the new LUN (migratepv), get the old LUN out of the VG (reducevg) and delete it. It might be sensible to do that during downtime because of performance degradation (depends on your system and what it does), but it is not necessary.
See above, that depends on what your subsystem supports and how a possible degradation of disk performance may interfere with the goals of your installation. Only you can take this decision, because you know your system best.
I hope this helps.
bakunin
I would like to add the if you have SVC (IBM SAN Volume Controller ) disks can actually be extended to a bigger size while the system is running.
cfgmgr
bootinfo -s hdiskxx ( this will now be bigger )
You can then just change the size of the PV for LVM by running
chvg -g yourvg
then
chfs -a size=+xxx /yourfilesystem