Quote:
Originally Posted by
Phat
I copy here again. Note that below info is taken from another machine which has big VG and scalable VG.
Big VG it has 2 parameters: Max PPs per VG and Max PPs per PV
OK, now i understand what you mean - sorry, my bad.
Yes, big VGs have still a limitation of how many PPs can reside on a single PV AND they have a restriction of how many PVs can be in a VG, although these limits are higher than in a classic VG. The scalable VG only has one upper limit and that is the number of PPs overall, in the whole VG. There is no limit of how many PPs can be in a single PV any more. You can set the maximum number of PPs for the
whole VG at the creation of the VG and my suggestion is to set it to the maximum possible of ~2 million PPs as i told you already.
Quote:
Originally Posted by
Phat
Like you said, we can increase LUNs in size at storage by adding 1 or more disks to the LUN.
ahem, no. A "LUN" consists already of many disk snippets (that is done inside the storage box) but it is presented as a single homogenous disk device to the OS. You can make such LUNs bigger (at least with certain storage systems) and this will - to the OS - look like the hard disk it has attached just grew in size. You do not "add another disk" or something such. To make use of such a grown disk first run
cfgmgr to make the OS aware of the new size, then run
chvg -g to make the LVM aware.
Quote:
Originally Posted by
Phat
I have 1 concern here, currently, the max PP of PV is limited at 2032 PPs x 128 MB = 260 GB. Because of this limitation, I cannot add the 1 TB PV whose PPs are greater than 2032 PPs.
If we grow the LUN in size example 500GB in total, it will breach the limits of 2032 PPs. Still acceptable from VG side?
This is why i told you to recreate the VG: a PP size of 128MB is just ridiculous. Do yourself a favour and when you recreate the VG select a PP size of 1GB or even 2GB. I mean, is there any chance you may want to change (increase or shrink) a filesystem on that VG in steps smaller than 1GB? Certainly not, i'd reckon. Therefore there is no reason to have such a small PP size at all.
Such a recreation of the VG (and the filesystems it contains) will give you the opportunity to rectify the filesystems too: if you still have JFS filesystems recreate them with JFS2, if you still use external log volumes change the new FSes to use inline logs.
I hope this helps.
bakunin