Moving a filesystem to an seperate LV.

[Mitchell Gaddy]

I wanted to know the proper way to move data from an filesystem on /var to its on seperate LV. I guess I'm looking for the proper syntax for the tar or dd command.

[James R. Ferguson]

Hi Mitchell:

You could use 'cpio' or 'tar' easily:

# cd srcdir && find . -depth -print | cpio -pudlmv dstdir

# cd srcdir && tar cf - . | ( cd dstdir && tar xpf - )

Regards!

...JRF...

[Mark Nieuwboer]

Hi Mitchell,

Why not use cp.

grtz. Mark

[Robert-Jan Goossens]

Hi Mitchell,

Create a new logical volume and mount it on mnt

# cd /var/xxx
# find . | cpio -pcmudv /mnt
# rm -r /var/xxx
# mkdir /var/xxx
# umount /mnt
mount the new filesystem on the /var/xxx mount point and add this to the /etc/fstab.

You will have to be sure that there are no open files inside this /var/xxx directory.

Hope this helps,
Robert-Jan

[Sivakumar TS]

Dear Mitchell,

1. If the other filesystem (destination) is already UP then you can use "cp" itself.

1a. mount the new f/s in a temp_mountpint

1b. use #cp -R -p

( The -p option preserves the permissions

1c. umount both existing&temp_mnt and mount the new f/s in the reqd mountpoint or make necessary changes in /etc/fstab and reboot the server.

Otherwise

2. use #tar -cvf /dev/rmt/0m /

and use #tar -xvf to restore back in the new lv.

With Regards,

Siva.

[Chan 007]

Mitchell,

Use CP or CPIO for doing that.

Also note, /var has few mounted file systems like /var/adm/crash etc, so if you do a find use -nodepth option.

Finally note that /var is required by system, so ensure that it is also mirrored to resolve a Single point failure.

Chan

[Alzhy]

Likely you're running 11.0 and above, so - the cleanest would be:

vxdump 0f - /var|(cd /destfs;vxrestore rf -)

Others:

CPIO:

cd /var;find ./ -depth -print|cpio -pdvmu /destdir

DD: Fastest (assuming destination LV is sized exactly as source - do prefrably in single user mode):

dd if=/dev/vg00/rlvolX bs=4096 of=/dev/vgXX/rlvolX

(where rlvolX is the raw LVOL name of your /var if you use regular LV names, rvar if using named LVOLS. Destivation LVOL should not be mounted. Also, fsck the destination LVOL after the dd is done.)

HTH.

[Lolupee]

Mitchell,

/var is a system area and why do you want to move data to another file system instead of extending the file system online.

If you must, you may have to be on single user level for some directory. can we know the specific directory you plan to move.

[Ajitkumar Rane]

Mitchell,


Use tar in a pipeline to copy the entire file system hierarchy under fromdir to todir:

cd fromdir ; tar cf - . | ( cd todir ; tar xf - )

This works fine, from my personel experience.


Rgds,

Ajit

[A. Clay Stephenson]

The cp command is an extremely poor choice for this. The data will be moved w/o problem but the metadata (those little things like file mode, owner, group, Xtime) will not be fully preserved even with cp -p. Use tar, cpio, or fbackup to preserve the metadata.

Moreover, generally the entire /var filesystem is not moved but rather directories beneath var are given their own mountpoints (e.g. /var/spool, /var/mail, /var/tmp, /var/adm/sw, /var/opt/omni --- depending upon your applications and needs). It's so easy to fill up /var/spool that it is an extremely good candidate for its own filesystem. Fill up /var/spool is really no big deal -- lp may break but filling up /var can kill your entire system.

[Lolupee]

Mitchell,

brief steps if you must mv directory.
make new file systems and mount on junk

mkdir /tmp/junk_new
mount /dev/vg00/lvol?? /tmp/junk_new

Move to your source files

cd /var/junk_old

tar cvf - *|(cd /tmp/junk_new; tar xvf -)

above would tar the files from /var/junk_old and dump them on /tmp/junk_new

after confirming the files are the same, then follow the next step

Hopefully, the files system or files you plan to move are those that could be moved withput an outage.

If the directory is a file system, try to mount, if it does then you may be ok. If not you might need to be on single user level before you can do that or maintenance level.

If it is a dirctory, if it is in use it could be difficult to mount on.

Let us knowthe directory in question.