Creating RAW Filesystem Using Command

[Amit Dixit_2]

Hi,
How can I create raw filesystem through
command

Eg: I want to create filesystem mydb with
size 2 GB

What command will i give ?

Thanks
Amit

[Jeroen Peereboom]

Amit,

a RAW FILESYSTEM? I hope I'm not still sleeping, but isn't that a contradictio in terminis?
Can you explain a little more?

What program / application is going to have access to it? Does it have a utility to 'format' the LV?

In general: Create an LV (lvcreate).

JP.

[Michael Tully · Accepted solution]

There is no such thing as a raw filesystem. There is logical volume which is raw, but once a filesystem has been placed on it, and mounted it becomes a cooked filesystem.

To create what I think your after assuming you have a volume group with some space.

e.g.
# lvcreate -n mylvol /dev/myvg
# lvextend -L 2048 /dev/myvg/mylvol
# newfs -F vxfs -o largefiles /dev/myvg/rmylvol
# mkdir /myfs
# mount /dev/myvg/mylvol /myfs

You wish to have it automatically mounted at the next reboot, add an entry like this to the /etc/fstab file.

/dev/myvg/mylvol /myfs vxfs rw,suid,delaylog,datainlog,largefiles 0 2

If you don't want to create it as a filesystem dont do the steps after 'lvextend'

[Sยภเl Kย๓คг]

Can you tell what exactly you neede.
regrads
SK

[Amit Dixit_2]

HI,
Sorry for puting wrong question ..
I wanted to know how to create a LVM using
lvcreate and it is a raw with no fs want to
use it for INFORMIX database.

Thanks,
Amit

[Bharat Katkar]

HI Amit,
Attempt to explain what you want:

1. Normally we create VG's first. SO suppose you have three disk's c0t1d0,d1,d3.
2. You create a Vg using:
# vgcreate vgname c0t1d0 c0t1d1...so on
3. Then you create LV's into it using:
# lvcreate
Now when you do lvcreate it doesn't have filesystem by default for that you have to do newfs. Now that you are not interested in file system but need raw device then don't do newfs and use the raw device created by lvcreate.
4. lvcreate create two file one is character device and other one is block device.
for e.g. /dev/vgxx/lvol1 and /dev/vgxx/rlvol1
So at this stage simpy go ahead and use /dev/vgxx/rlvol1 device file which you can treat it as Raw File System for your Informix Database.

Hope that helps.
REgards,