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Date: | Wed, 11 Dec 2013 14:55:09 +0100 |
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On 10. des. 2013 20:43, Jeff Siddall wrote:
> On 12/09/2013 11:20 PM, ToddAndMargo wrote:
>>> then you absolutely want to be running
>>> them against a snapshot rather than a live FS and LVM makes this easy.
>>
>> Never really cared for LVM. Always used the direct partition approach.
>
> Well, perhaps I can try to convince you some more.
>
> Take another example of upgrading to a bigger disk. Huge PITA if you
> use direct partitions. Shut the system down and use a live OS or
> something while you move over all the data -- which could take hours or
> days depending on what you need to move. If you are really obsessive
> you probably want to make sure nothing got lost in the move so there is
> a whole compare exercise after it finishes.
>
> If you have LVM you simply install your new drive (assuming you can
> hotswap you don't even have to shutdown for that) run pvcreate, vgextend
> and then pvmove. Some hours (or days) later it finishes and your data
> is magically on the new disk without even a moment of downtime.
>
> A lvextend and a resize2fs (or whatever utility resizes the FS you use)
> and you can start using the extra space, still with no downtime.
>
> That is pure sysadmin gold!
>
> BTW: I also use LVM on my offsite backup disks. I just use the same
> volume group/volume name on all the disks. Works with LUKS also.
I'll even recomend fsadm, which makes resizing live filesystems even
easier and safer. I've even done resize of / on a running system
without any issues. The fsadm utility will do much of the filesystem
tasks for you, in a safe an controlled manner.
# fsadm -v -l resize /dev/vg.../lv... $NEWSIZE
If you're more cautious, you can add -n (--dry-run) and even do a 'fsadm
check' first. This takes care of resizing all the needed pieces. But
'fsadm check' can only be done on an unmounted volume, iirc.
I have not tried fsadm on a direct partition, though. It might also
work there.
These LVM features can also be very useful if you're using virtual
machines with LVM, as adding and removing virtual drives on-the-fly is
very easy in such environments.
kind regards,
David Sommerseth
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