urilabob
14th October 2005, 04:54 AM
(sorry about the long header, I want to make sure other users with this problem can google it relatively easily; what's also why I have reposted it, rather than just append it to my original request for help)
Firstly, if you are planning on installing FC4, consider very seriously whether you want to use the default ("automatic") partitioning scheme. if you do use it, it will be extremely difficult at a later stage to tailor it. If you think you might later need to restructure the partitioning, you should read the documentation on logical volumes, noting that they are easy to extend but very difficult to shrink. You may wish to consider creating a partitioning scheme with relatively small logical volumes, for later extension.
If you do get caught in this way, as I was, you may find my experiences useful. But first, let me emphasise just how disastrous this default is. I've been using various unix systems for almost 30 years. I'm not a sysadmin, but I am a reasonably experienced user, and know my way around unix systems. It has taken me a week's solid work to find a solution to the problems created by the FC4 automatic partitioning scheme. That _doesn't_ seem to me a user-friendly default.
Please note that all I am reporting is that this solution worked for me. If you decide to do something similar, please understand I am _not_ an lvm expert. You should evaluate for yourself whether it might work for you, and make sure that you fully understand the risks. Especially, make sure you have backed up your system fully first. I would not have attempted this before I discovered dar (http://dar.linux.free.fr/), and was certain I had the system fully backed up.
A. I ran Knoppix
1. Downloaded Knoppix and burned to CD (http://www.knoppix.net/)
2. Booted Knoppix on the computer
B. Got LVM Running on Knoppix (from http://www.knoppix.net/wiki/LVM2)
1. configured internet connection under Knoppix
2. modprobe dm-mod
3. apt-get update
4. apt-get install lvm-common lvm2
5. lndir /lib/lvm-200/ /usr/sbin/
C. Resized the volume (based on http://www.linuxquestions.org/questions/showthread.php?s=&threadid=337823&highlight=resize+lvm)
The volume I was resizing was /dev/VolGroup00/LogVol00
I was resizing to 58G
It's _crucial_ that the parameters in resize2fs and in lvreduce match
Otherwise you will probably destroy your filesystem.
I would strongly recommend not using resize2fs or lvreduce until you have read
_and understood_ their man pages. If you don't understand what you are doing
here, and especially the differences between filesystems and partitions, you
don't know enough to do this safely.
It's also crucial that you allow enough space for the files already there, as again
you may well destroy your filesystem if it's too small (My files used only
about 10G, so I wasn't worried, there was plenty of room. I'm not certain how
to check the exact size, though I would guess the sizes reported by df are
probably accurate - I know the sizes reported by du may be too large; anyone
expert enough to give an accurate opinion? But in any case, you need to allow a
margin, probably at least 20%, so it doesn't matter too much.)
1. vgscan
2. vgchange -a y?3. e2fsck /dev/VolGroup00/LogVol00?4. resize2fs -p /dev/VolGroup00/LogVol00 58G?5. lvreduce -L58G /dev/VolGroup00/LogVol00
I strongly recommend including the -p parameter in resize2fs. My resize took a couple of hours, and (because I omitted this), I had no way of confirming that it was actually proceeding rather than just hung. Fortunately, I resisted the temptation to reboot... Unlike the post mentioned above, I did not find it necessary to use the -f options. I would strongly recommend _not_ using the -f option in any of these commands until you are certain why the command is failing, and that forcing it will not cause a problem.
I then exited Knoppix and rebooted Fedora. The filesystem and partition had been shrunk as I had hoped and prayed (believe me, I was sweating as I did the final check). I was able to use the Logical Volume Manager to create additional logical volumes in the freed space. The system appears to be working fine.
Firstly, if you are planning on installing FC4, consider very seriously whether you want to use the default ("automatic") partitioning scheme. if you do use it, it will be extremely difficult at a later stage to tailor it. If you think you might later need to restructure the partitioning, you should read the documentation on logical volumes, noting that they are easy to extend but very difficult to shrink. You may wish to consider creating a partitioning scheme with relatively small logical volumes, for later extension.
If you do get caught in this way, as I was, you may find my experiences useful. But first, let me emphasise just how disastrous this default is. I've been using various unix systems for almost 30 years. I'm not a sysadmin, but I am a reasonably experienced user, and know my way around unix systems. It has taken me a week's solid work to find a solution to the problems created by the FC4 automatic partitioning scheme. That _doesn't_ seem to me a user-friendly default.
Please note that all I am reporting is that this solution worked for me. If you decide to do something similar, please understand I am _not_ an lvm expert. You should evaluate for yourself whether it might work for you, and make sure that you fully understand the risks. Especially, make sure you have backed up your system fully first. I would not have attempted this before I discovered dar (http://dar.linux.free.fr/), and was certain I had the system fully backed up.
A. I ran Knoppix
1. Downloaded Knoppix and burned to CD (http://www.knoppix.net/)
2. Booted Knoppix on the computer
B. Got LVM Running on Knoppix (from http://www.knoppix.net/wiki/LVM2)
1. configured internet connection under Knoppix
2. modprobe dm-mod
3. apt-get update
4. apt-get install lvm-common lvm2
5. lndir /lib/lvm-200/ /usr/sbin/
C. Resized the volume (based on http://www.linuxquestions.org/questions/showthread.php?s=&threadid=337823&highlight=resize+lvm)
The volume I was resizing was /dev/VolGroup00/LogVol00
I was resizing to 58G
It's _crucial_ that the parameters in resize2fs and in lvreduce match
Otherwise you will probably destroy your filesystem.
I would strongly recommend not using resize2fs or lvreduce until you have read
_and understood_ their man pages. If you don't understand what you are doing
here, and especially the differences between filesystems and partitions, you
don't know enough to do this safely.
It's also crucial that you allow enough space for the files already there, as again
you may well destroy your filesystem if it's too small (My files used only
about 10G, so I wasn't worried, there was plenty of room. I'm not certain how
to check the exact size, though I would guess the sizes reported by df are
probably accurate - I know the sizes reported by du may be too large; anyone
expert enough to give an accurate opinion? But in any case, you need to allow a
margin, probably at least 20%, so it doesn't matter too much.)
1. vgscan
2. vgchange -a y?3. e2fsck /dev/VolGroup00/LogVol00?4. resize2fs -p /dev/VolGroup00/LogVol00 58G?5. lvreduce -L58G /dev/VolGroup00/LogVol00
I strongly recommend including the -p parameter in resize2fs. My resize took a couple of hours, and (because I omitted this), I had no way of confirming that it was actually proceeding rather than just hung. Fortunately, I resisted the temptation to reboot... Unlike the post mentioned above, I did not find it necessary to use the -f options. I would strongly recommend _not_ using the -f option in any of these commands until you are certain why the command is failing, and that forcing it will not cause a problem.
I then exited Knoppix and rebooted Fedora. The filesystem and partition had been shrunk as I had hoped and prayed (believe me, I was sweating as I did the final check). I was able to use the Logical Volume Manager to create additional logical volumes in the freed space. The system appears to be working fine.
