making a new disk a "raw disk"

[Chet Woods]

Hi all,
Hope everyone is having a great Friday the 13th - no black cats, broken mirrors, etc...Anyway, here's my question - I am having a couple of disks put into one of my servers tonight, and I'll need to make them "raw" so my dba can use if for Informix. Is there anything that I need to do?? I think there is but, can't remember what it is.

Thanks,
Chet

[Lasse Knudsen · Accepted solution]

Nothing special to do - The device files are created automatically in /dev/rdsk/yadiyadi.

You need perhaps to change the permissions on the files so that 'informix' can acces them. (I am not quite sure if the perms are retained when you reboot - I think so though)

You could off course add some nice links with a more descriptive name.

/Allan

[Chet Woods]

Thanks, Allen

[Chet Woods]

Thanks, Allen
I really wont know if it works until later on tonight when I actually do this, but, I was doubting myself a little and wanted to make sure.

I appreciate it.

[A. Clay Stephenson]

Hi Chet:

Allan's answer is correct when you are talking about entire disks but you can also set up raw logical volumes to use part of a disk as raw or span multiple disks into one logical volume
or stripe across multilple disks for still better io.

The idea is you create a volume group and add your new disks to. Then you create logical volumes but do not install filesystems on them. This can all be done via sam or from the shell.

Your devices then becomes /dev/vg05/rlvol1, /dev/vg05/rlvol2, ...

This would be my way to do this as it gives you greater flexability for very little more effort. From a performance standpoint, the logical volumes could give you very slightly poorer performer in the worst case and markedly better performer in the best (and more typical case). Moreover, you could even use some of the disk space as a filesystem without taking a hit.

If this is your first time, I'd use sam otherwise man pvcreate,vgcreate,vgchange,lvcreate for details.


Regards, Clay

[MANOJ SRIVASTAVA]

Hi Chet

Since you would be adding and linking so you may also be intrested to know how to change permissions , ownerships of the links etc , man ln thats it. Otherwise just add the disk and u may be intrested to use SAM to cretae the raw partitions .

Manoj Srivastava