RE: 4 Primary partitions limitations

From: Bort, Guillermo <>
Date: Fri, 21 Nov 2008 05:08:02 -0600
Message-ID: <>

If I understand this correctly, the luns will be presented a different 'disks' to Linux, such as /dev/sdb, /dev/sdc, etc. in such case, you can create up to four primary partitions in each of those 'disks'. As for ASM, since it uses raw devices on linux, you can create extended partitions and it works fine.

I have a RHEL4U6 with Oracle10g ( Database is completely in ASM (except for a few testing datafiles) and disk configuration due to hardware restrictions is:

/dev/sda1		/boot
/dev/sda2		/
/dev/sda3		/var
/dev/sda4		extended

/dev/sda5 /usr
/dev/sda6 /var/lib/vmware(something)
/dev/sda7 /u01
/dev/sda8 raw
/dev/sda9 raw
/dev/sda10 swap

So, I guess this is all aimed to show that while you certainly *can* have extended partitions as ASM Diskgroups, it's not necessary to create extended partition on secondary disks.

HTH Guillermo Alan Bort
DBA / DBA Main Team

EDS, an HP company
Arias 1851
Ciudad Autonoma de Buenos Aires (C1429DXC) Argentina

Tel: +54 11 4704-3132

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so you can deliver on yours.

-----Original Message-----
From: [] On Behalf Of hrishy Sent: Friday, November 21, 2008 6:28 AM To:
Subject: 4 Primary partitions limitations


I am planning to use ASM and following diskgroups


I have 4 Usable Luns from the SAN that are presented to the host o/s which is rhel 5

I have already created 3 primary partitions on Linux


These partitions are under Linux LVM(Logical Volume Manager)

since BIOS supports only 4 primary partitions how can i use the 4 usable luns.

should i be creating a extended partitions on the LUNS that are presented to the host operating system



i0zX+n{+i^ Received on Fri Nov 21 2008 - 05:08:02 CST

Original text of this message