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Re: [K12OSN] /var is full!

We have done some testing with decreasing lvol and filesystem sizes on various HP systems, "just for fun", to see the results, and it worked without incident about 80% of the time. But with the other 20%, we got file corruption. So, we don't do decreases where the data integrity matters, and instead we just create a new lvol and move the data to it first. But even that's rare, less than once a year I'd say; our users just don't come to us saying "That partition you gave us is just too big and we'd like to give some of it back". ;-)

Now back to our regularly schedules topic (k12ltsp)...


Julius Szelagiewicz wrote:
On Thu, 23 Oct 2003, Petre Scheie wrote:

I, too, work in an HP-UX shop, and HP's lvm is nice.  RH8 and 9 both
have support for LVM, and I've run it on both without any problems, but
not really in production use, just testing.  It may be worth noting that
RH originally provided support for lvm in its Advanced Server 2.1 series
(its 'corporate' version) but pulled it because of stability concerns, I
think.  However, AS version 3.0 is now out (according to their website)
and one of the things promised in 3.0 is lvm, which we will be getting
shortly.  But, as I said, it's always been available in RH 8 & 9, and
I've had no trouble with it on those versions.  I *do* have a couple of
criticisms, however, directed at RH: one, there's no built-in gui tool
for managing disks and lvs; why?  This should have been added years ago.
 Fortunately, webmin has a pretty good module for managing lvs, and is
what I use.  Two, why doesn't RH use lvm by default?  Even with just a
single-disk system, it should put that into a volume group, and then
create logical volumes from that for the various mount points.  Why?
Because that way, when you install Linux onto, say, an 80GB disk, it
doesn't just put the OS and stuff onto a 4GB root partition, and waste
the other 76GB by putting it all into /home, where you may or may not
need it.  Rather, it would put 4GB into various system partitions, plus,
say, 4GB for /home, and leave the rest unallocated, but which can be
added to existing lvs as necessary or used to create new lvs.  The whole
point of lvm is it allows you to dynamically increase the lvs on the
fly.  (In theory, decreasing lvs should be possible, and even HP
provides tools for doing so, but I don't trust it to not trash the data
on the lv, nor does anyone else I know--but there's not much need for
it, so it's no big deal.)  LVM also makes adding additional disks
easier: In Richard's case, he could add a second disk to the volume
group, and then use however much space he wants to add to /var without
having to fool around with creating additional partitions and figuring
out which subdirectory in /var to use as its mount point.

I encourage everyone to explore the lvm module in webmin.  Once you get
the hang of it, you'll never go back.

	LVM is just great, and on HP, with OnlineJFS the increase and
*decrease* of the lvols and filsystems works on the fly just fine. I used
it in production environment with no detrimental effects - on active
filesystems. HP uses Veritas Journaling File System, which essentially is
the core of ext3. You are right that LVM should be the default at disk
setup time. julius

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