I got a lot of ideas from this thread: http://www.linuxquestions.org/questi...ompare+distros

But my question seemed to me different enough to justify its own thread. Hope you will agree.

I may be going about this the very hard way.

My objective is to be able to compare a number of different distributions of Linux using common files for my everyday work. Example: I'll use the Opera browser in all distros; I want to be able to have the same bookmarks in whatever distro I happen to be using that day. If I add bookmarks to Opera in distro "A", I want them to show up when I open Opera in distro "B". Likewise for the emails I receive/send in kmail. That way I can work several days in distro "A", accumulating bookmarks and mails, and then move to distro "B" or "C" or "H" without losing the earlier bookmarks/mails, and I can compare each distro on even terms.

I created a "common" partition (hda5) and moved to it Opera's bookmarks file and kmail's mail folder. I also have all my text files and scripts there. Then in "A" distro, I replaced ~/.opera/opera6.adr with a symlink to the real bookmarks file in hda5/.opera. I did the similar thing for kmail's mail folder. Kate has no problem handling all my text files in the common partition. I've done the same for each distro installed. Ideally, any app would run in any distro without reconfiguring, and using the common data files.

But Opera will not accept its vlinks.dat (visited links) file through a symlink, and kmail will not accept some of the emails through a symlink. Other configuration and data files are not functioning properly through the symlinks. So my method of being able to compare distros isn't working out.

I keep reading about using a separate partition for /home. I wondered if I could mount that same partition in each distro. However, a friend told me you can't use one distro's /home for another distro so I'm afraid to try it.

Would mounting the same /home partition in each separate distro work? Or is there a simple way to be able to compare distros without losing the work I did in the last one when I move to the next one?

In faith, Dave
dave@christos.cjb.net
Viva Texas

Hello, Dave.

I'm pretty sure it's possible to share a home partition between two distributions simultaneously as long as you don't let either distribution replay the journaling logs for your home partition and try to "fix" discrepancies. Otherwise they'll constantly try to put back the home partition to how it remembered it being when the computer was last rebooted. That would cause all kinds of problems. Unless I'm mistaken, you should be able to simply disable file system checking on that partition in each distribution's /etc/fstab (the last two digits of each line are involved with this; I think changing them to "0 0" should do the trick.)

Also, I know for a fact that it's entirely possible to simply install your new distribution over your current one and not reformat your home partition. Just mount it at /home and you're ready to go. I've done this several times and it works like a charm.

I hope this helps.

--Dane

Hi Dane. Thanks for the response. I checked fstab and the last two entries everywhere are 0 0. I'm assuming I'd have to check that in each distro I installed.

I'm not going to be installing a new distro over an old one, at least not right away. Instead, I'll install a new distro on a new partition. I have Xandros 2 on hda1, Fedora 1 on hdb1, and Ubuntu on hdb2. That leaves 7 partitions free for experimentation. From the size of the /home directory on Xandros, 7.3MB, my 2GB common partition (hda5) will easily handle /home.

A question: I can use a new distro's installer to mount the common /home partition, but I'm not sure how to make my already-installed distros use that common /home. I'm assuming I can change fstab, but I'm not sure how. My current /etc/fstab is:

--------------------------------------------------------------------------------------------------------------------------------------------------------------

# /etc/fstab -- static file system information
# auto generation: on
# generated by: /sbin/etcdev2fstab
#
# NOTE: to make this file readable, it has been formatted for 132 columns
#
#<device> <mountpoint> <fstype> <options> <dbg> <pass>
/dev/ide/host0/bus0/target0/lun0/part1 / ext3 defaults 0 0
/dev/ide/host0/bus0/target0/lun0/part3 /disks/fedora ext3 defaults 0 0
/dev/ide/host0/bus0/target1/lun0/part1 /disks/fedora_2 ext3 defaults 0 0
/dev/ide/host0/bus0/target0/lun0/part5 /disks/hda5 ext3 defaults 0 0
/dev/ide/host0/bus0/target0/lun0/part7 /disks/hda7 ext3 defaults 0 0
/dev/ide/host0/bus0/target0/lun0/part8 /disks/hda8 ext3 defaults 0 0
/dev/ide/host0/bus0/target1/lun0/part3 /disks/hdb3 ext3 defaults 0 0
/dev/ide/host0/bus0/target1/lun0/part5 /disks/hdb5 ext3 defaults 0 0 <------
/dev/ide/host0/bus0/target1/lun0/part7 /disks/hdb7 ext3 defaults 0 0
/dev/ide/host0/bus0/target1/lun0/part8 /disks/hdb8 ext3 defaults 0 0
/dev/ide/host0/bus0/target1/lun0/part2 /disks/ubuntu ext3 defaults 0 0
/dev/ide/host0/bus0/target0/lun0/part2 /disks/welcome ext3 defaults 0 0
/dev/cdroms/cdrom0 /mnt/cdrom0 iso9660 ro,nosuid,nodev,exec,user,noauto,async,unhide 0 0
/dev/cdroms/cdrom1 /mnt/cdrom1 iso9660 ro,nosuid,nodev,exec,user,noauto,async,unhide 0 0
/dev/fd0 /mnt/fd0 auto rw,nosuid,nodev,exec,nouser,noauto,async 0 0
proc /proc proc rw 0 0
usbdevfs /proc/bus/usb usbdevfs rw,devmode=0666 0 0
/dev/ide/host0/bus0/target0/lun0/part6 none swap sw 0 0
/dev/ide/host0/bus0/target1/lun0/part6 none swap sw 0 0

---------------------------------------------------------------------------------------------------------------------------------------------------------------------

This entry:
/dev/ide/host0/bus0/target1/lun0/part5 /disks/hdb5 ext3 defaults 0 0

could it be changed to read:
/dev/ide/host0/bus0/target1/lun0/part5 /home ext3 defaults 0 0

????

In faith, Dave
dave@christos.cjb.net
Viva Texas

Hi, Dave.

I think you're on the right track. The following looks like it'll work well for whichever distro's fstab it came from:

Since most distros identify their drives differently in the fstab, I would suggest this on any others that don't seem to follow this format:

That last bit will work in Red Hat, Slackware, Mandrake, and probably most others.

A note of caution: be sure to back up everything that you think is important on your home partition, since I'm not 100% certain this is going to work...but by all my reasoning it should without problems.

Let me know when you try this; I'm interested in knowing how it turns out. (Private message me if you want.)

--Dane

Dane:

Again, thanks for the response. Yes, Xandros has their own way of naming the other partitions :^>. And, besides the common partition hda5 (to be mounted as /home), I also made a backup partition hdb5, same size; it will mirror hda5. My plan is to copy an entire /home partition to hda5, then change fstab to mount hda5 as /home. I'm assuming the mount will destroy the old info that distro's old /home. I'm also assumimg I'll have to do all that as root.

Question: will I be better off to add "user" after "defaults" in the hda5 line of fstab? I read that that will lessen read-write problems between distro partitions. ("defaults,user 0 0")

I'm going to first try changing fstab in Ubuntu (which I'm not all that fond of). If that works, I'll try installing FC3 and mounting hda5 there as /home. If they work together, fine; if not, it won't mess up Xandros2 or FC1 which I'll leave at least for the while as they are. They are both fairly well tamed and their essential files work together pretty well using symlinks

I see you have Slackware 10. I tried to install it from a CD attached to LinuxFormat Magazine but it's broken. Later on after I get this /home thing straightened out I may ask you some questions about it. In 3 years now, starting with Slack 7.1.1, I haven't been able to install Slackware. I'm trying for a good .deb, .rpm, .tgz, and .src distro to get experience with them all and decide which I like best. For the future, I'm looking at Slackware, DSL, Knoppix (to HD), and others like MEPIS. Plus the FC3 I'm going to install after working on Ubuntu.

Also, I will keep your offer of private message handy. Will it be better to do this by email rather than on this forum?

In faith, Dave
dave@christos.cjb.net
Viva Texas

Hi, Dave.

You shouldn't have to worry about anything deleting stuff on your /home partition (eg. while installing FC3). I've successfully transferred my /home directory from Mandrake to Slackware, to Slackware again, reformatting all other partitions but leaving /home intact. It should be a breaze; I just mention backing things up in case that something goes wrong, which never happens with Linux ;-) .

The changes you're looking to make in your fstab are correct. Adding "user" like that will allow users other than root to access that partition. Just for reference, here's my /etc/fstab:

Line 4 should be of most interest. I'm not sure why, but on my system it lets me get into /home without root access; I think it has to do with directory permissions.... Also of note are the sections for "Supermount" and "Captive-NTFS". Most Linux distributions (not Slackware) come with the Supermount kernel patch installed; I installed it from scratch. It allows you to use floppies, etc. without having to mount them first and unmount them later. Captive-NTFS is a program that allows read-write access to NTFS partitions on kernels 2.6.7 and older. (It's currently unmaintained.)

I think this conversation would be best kept to LinuxQuestions.org so that other people can benefit from anything we figure out. I said you could message me because if it takes you a while to get around to making all these changes the thread may stop forwarding replies to my email account.

As for Slackware, I'd be glad to help; I've been meaning to write an FAQ for a little while now. When you do get around to installing Slackware start a new thread entitled something like "Slackware FAQ" in the Slackware forum and email me to let me know it's there.

Let's see how far this gets you... :-)

--Dane


P.S. Now that I've given it some more thought, I don't think it would hurt to let Linux check the /home partition on boot; the journal is kept on that partition, not in the various root partitions you have. Changing the last two numbers in the fstab to "1 2" will likely PREVENT, not cause data loss. Sorry for the error.

I may have done it wrong. Why does that not surprise me???

I mounted my hda5 as /home when I reinstalled Ubuntu (I managed to corrupt Ubuntu messing around :^>). I had copied Ubuntu's /home/dave to hda5, so I expected to get those files back and, in a way, I did. After the reinstall, they appeared in /home along with a directory for Dave which contained a new /home for Ubuntu. I think I could have moved the old /home into a directory hda5/dave and then reinstalled mounting that as /home so that the files would have appeared in /home/dave, but before I could try it I ran into a kind of "permissions hell". Having the user option in fstab didn't make any difference. All the files I wanted to share between distros had new owners... 1000 for some, 500 for some, staff for some, syslog for some, many different owners. I couldn't access any of my essential files. Eventually I rebooted as root and went in and manually adjusted the permissions for each individual file and directory (maybe 300 of them, took me almost two hours :^>). I'm afraid I said some unchristian words in the process, but it's all straight now.

The bad part is I have no idea why my permissions all went north on me. There was no consistent pattern that I could detect. It seemed like the owners, groups, and permissions had been randomly scrambled. So, at the moment, I'm back to sharing the essential files through symlinks -- which isn't ideal but does work well enough.

However, you were able to share your /home between slackware and mandrake, which is essentially what I'm trying to do between ubuntu and fedora (except I chickened out before I actually tried to install FC3 with ubuntu's /home/dave). Did you run into any permissions issues in one distro working with files you had created earlier in the other? Or with permissions/owners changing on you when you went from one distro to the other? Or conflicts in the config or program files for your various apps? What about running, for example, KDE in one distro and Gnome in the other? Were you running both distros alternately?

In my slackware install, all the files seem to be there (except for /boot/initrd.img) but it boots broken and won't recognize the password I made during the install. However, it may be some days before I get to it.

In faith, Dave
dave@christos.cjb.net
Viva Texas

Hi, Dave.

Just to clarify, I didn't ever have Mandrake and Slackware installed at the same time. I had Mandrake installed by its self, then decided to switch to Slackware without reformatting my /home directory. I then messed up Slackware and reinstalled it without touching home. It went smoothly and I didn't come upon any of the permissions problems that you experienced. I suspect that those problems are Ubuntu's fault; I see no reason why any distro would mess with the permissions of pre-existing directories unless it had some fancy feature it wanted to use that required it. Here are some commands that could help you avoid those sadly unchristian words in the future:

This will change the ownership of all the files in /home (recursively) to <user> and <group>. It will also recursively add read and write permissions for everybody to all files in /home. I would like to note, however, that any sane distribution should leave these as they are. I know Slackware does at least.

For Slackware, what version are you using? In the latest version no initrd is necessary (at least with my setup), so if it boots, don't worry about it. The password thing is a bit odd, but it's easily fixed. First just try logging in as root and just hit enter for the password. If that doesn't work, boot up one of your other distributions (or use a live CD, such as Slackware disk 2) and mount the partition with Slackware on it as read-write. Now open /etc/shadow on that partition and delete everything between the first and second colons on the line that starts with "root". Save the file and reboot. You will now be able to log in without entering a password. Once you're in just type "passwd" and make a new one. Voila!

It's perfectly fine to run one GUI in one distribution and another in a different distribution. Just make sure that each distribution has its GUI installed specifically for that partition, and not shared with another distro.

Keep plugging!

--Dane

If you just change the UID of your users (Standard users, NOT any service accounts, like syslog, root (Which always should be 0 anyway), cups, or whatever the distributions call them) to the same thing across all distributions, you should be well on your way to a shared /home.

Remember that you need to change the UID in both /etc/passwd and /etc/shadow...

Try it out on your Ubuntu dist, if you were going to remove that one anyway, and then change to the UID from one of the others... Remember to check if another account uses that UID.

Good luck!

1) Yes, I discovered that recursive feature in chown and chmod in doing some belated studying on permssions. Wish I had seen that before I changed them all manually :^>. I'll more than likely try using a common /home/dave again by creating a dave directory in the common partition, placing Ubuntu's /home/dave/ in there, and then mounting the common partition so that the home files wind up in /home/dave rather than in /home. That may be what I didn't do right earlier. I have noted the permissions don't open up until the dave directory in /home/.

2) The Slackware is v10 from the LinuxFormat Magazine CD. I'll try what you said about fixing the password thing and will let you know.

>>> Just make sure that each distribution has its GUI installed specifically for that partition, and not shared with another distro. <<<

How do I do that if I'm using a common /home/dave?

In faith, Dave
dave@christos.cjb.net
Viva Texas

Hi, everybody.

LosD: That's a good idea about making all the UIDs the same; I'm glad you mentioned it.

Dave: When you install a GUI (KDE, Gnome, whatever) it installs its files in several places: /usr, /opt, /lib, /home, etc. The only stuff it stores in /home is your settings for the desktop, K menu, etc. This means that the only thing that will be the same for two distributions will be your personal settings; the libraries and system files will be stored separately on the different "/" partitions. The only problem you're likely to face is having a bunch of "dead" links to programs that are installed in one distro and not another. This won't cause any real problems; it'll just be a bit irritating if anything.

As far as I know, those Slackware 10 CDs should be OK, so don't worry about bad media.

Good luck!

--Dane

Please forgive my delayed reply: My alternative non-linux life rared up and demanded attention. And I appreciate y'alls help but I'm going to have to give up on establishing a common /home for different distros. Seems whatever I've tried has caused problems and the fixes have caused more problems and I've missed a lot of time which could have been spent comparing :^>. It feels like I'm going around in circles biting my tail. My essential programs (Opera, kmail, and OpenOffice) don't want to run in different distros from a common /home, or they keep re-setting themselves to default and I have to re-configure from scratch each time I change distros or even reopen the program in the same distro. Even the -personaldir operand for Opera only worked partly; some things came back on reopening Opera and some things reset to defaults... and I had to keep agreeing to Opera's license widget each time I opened the thing.

Anyway, my essential files, Opera's bookmarks and kmail's stored emails, can be used through symlinks and the permissions/owners stay OK. Those plus my text files and OOo files are useable from distro to distro as-is, and I can configure the applications in each distro, and at least get back to comparing!! I have Fedora Core 3, Damn Small Linux 0.9.2, and Gentoo 2004.2, awaiting attention. Maybe later when I understand more about Linux I'll be able to return to trying a common /home.

Thank you.

Re Slackware, I'll try editing the /etc/shadow file from Xandros' root before I try reinstalling it.

In faith, Dave
dave@christos.cjb.net
Viva Texas

Hi everybody.

Too bad about the shared /home not working out. I do have a rather important detail about Slackware that seemed to slip my mind before: when you first install it, the root password is set to "toor" (if I remember correctly). Good luck!

--Dane

Linux... Ya' can't get there from here :^>. If ya' could last week you can't this week. (I think it may be compiled into the kernel).

Last week Slackware booted as far as wanting the root password, and then refused to recognize my password. This week it won't boot at all :^>. It gives me these new messages:

>>>
FAT: bogus logical sector size 0
UMSDOS: msdos_read_super failed, mount aborted
FAT: bogus logical sector size 0
FAT: bogus logical sector size 0
sh-2021: reiserfs_read_super: can not find reiserfs on ide0 (3,6)
Kernel panic: VFS: Unable to mount root fs on 03:06
<<<

The partition (hda2) is formatted ext3. The only thing I changed is that I put Slackware back into Grub's menu.lst:

>>>
title Slackware 10, kernel 2.4.26 (on hda2)
root (hd0,1)
kernel /boot/vmlinuz-ide-2.4.26
savedefault
boot
<<<

Reinstall? Or is there an easier way?

In faith, Dave
dave@christos.cjb.net
Viva Texas

Hmmm...I'm not sure about all those errors, but it seems that it's looking for a DOS or Windows partition where it should be looking for an ext3 partition. Things to try:

1. Make sure that you've got the right hard drive partition listed in GRUB.
2. Make sure you have the right filesystem type listed in Slackware's /etc/fstab
3. Look up a GRUB how-to and check over the entry (I'm not very familiar with GRUB; I'm a LILO kind of guy)

Good luck with that!

--Dane