-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Scott Silva Sent: Friday, May 04, 2007 1:16 PM To: centos@centos.org Subject: [CentOS] Re: LVM Resizing Problem
Al Sparks spake the following on 5/2/2007 6:59 PM:
I'm new to lvm. I decided to decrease the space of a
logical volume.
So I did a: $ df -m Filesystem 1M-blocks Used Available Use%
Mounted on
/dev/mapper/VolGroup00-LogVol00 1953 251 1602 14% / /dev/sda2 494 21 448 5% /boot tmpfs 1014 0 1014 0% /dev/shm /dev/mapper/VolGroup00-LogVol05 48481 6685 39295 15% /home /dev/mapper/VolGroup00-LogVol03 961 18 894 2% /tmp /dev/mapper/VolGroup00-LogVol01 7781 2051 5329 28% /usr /dev/mapper/VolGroup00-LogVol02 5239 327 4642 7% /var
$ sudo lvm lvreduce -L -1000M /dev/VolGroup00/LogVol05 Rounding up size to full physical extent 992.00 MB WARNING: Reducing active and open logical volume to 47.91 GB THIS MAY DESTROY YOUR DATA (filesystem etc.)Do you really want to reduce LogVol05? [y/n]: y Reducing logical volume LogVol05 to 47.91 GB Logical volume LogVol05 successfully resized
LVM even warned you --IN CAPS-- "THIS MAY DESTROY YOUR DATA". I guess it was right. I haven't had much luck with reducing a volume below its initial size. I usually make a new LV and rsync or cp -a the data over to it. I try to leave some free space just for this. Or add a drive temporarily.
Were the LV calculations done in the VG's extent size unit?
Most people forget LVM rounds to the closest whole extent in it's calculations which I believe is 4MB by default, so care must be taken to make sure any file system fits comfortably in there first.
-Ross
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