View internal disks and Setup mirroring after OS install

[Hasan Saiyid]

Hi All,
I have a HP Proliant with RHEL 5.2 installed. I have been told that it has 4 internal disks, 2 72GB and 2 146GB. I need to setup oracle filesystems on the 2 146GB drives with mirroring. (The 72GB drive that contains the OS should also be mirrored once I know how to)

The first problem is that fdisk -l only shows 2 disks ..?? instead of 4, I thought maybe software RAID mirroring was setup but that is not the case, plus mdadm -Q shows those devices are not md devices. Here's the output:
==============================================
(fdisk -l output, omitting the SAN devices)
Disk /dev/cciss/c0d0: 73.3 GB, 73372631040 bytes
255 heads, 32 sectors/track, 17562 cylinders
Units = cylinders of 8160 * 512 = 4177920 bytes

Device Boot Start End Blocks Id System
/dev/cciss/c0d0p1 * 1 25 101984 83 Linux
/dev/cciss/c0d0p2 26 2535 10240800 83 Linux
/dev/cciss/c0d0p3 2536 4041 6144480 83 Linux
/dev/cciss/c0d0p4 4042 17562 55165680 5 Extended
/dev/cciss/c0d0p5 4042 5045 4096304 83 Linux
/dev/cciss/c0d0p6 5046 5798 3072224 82 Linux swap / Solaris
/dev/cciss/c0d0p7 5799 6049 1024064 83 Linux
/dev/cciss/c0d0p8 6050 17447 46503824 83 Linux
/dev/cciss/c0d0p9 17448 17562 469184 8e Linux LVM

Disk /dev/cciss/c0d1: 146.7 GB, 146778685440 bytes
255 heads, 63 sectors/track, 17844 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/cciss/c0d1p1 * 1 17844 143331898+ 8e Linux LVM

root@host# cat /proc/partitions
major minor #blocks name

104 0 71652960 cciss/c0d0
104 1 101984 cciss/c0d0p1
104 2 10240800 cciss/c0d0p2
104 3 6144480 cciss/c0d0p3
104 4 1 cciss/c0d0p4
104 5 4096304 cciss/c0d0p5
104 6 3072224 cciss/c0d0p6
104 7 1024064 cciss/c0d0p7
104 8 46503824 cciss/c0d0p8
104 9 469184 cciss/c0d0p9
104 16 143338560 cciss/c0d1
104 17 143331898 cciss/c0d1p1
(omitted SAN disks)

root@host# mdadm -Q /dev/cciss/c0d0
/dev/cciss/c0d0: is not an md array
/dev/cciss/c0d0: No md super block found, not an md component.
root@host# mdadm -Q /dev/cciss/c0d1
/dev/cciss/c0d1: is not an md array
/dev/cciss/c0d1: No md super block found, not an md component.

root@host# cat /etc/issue
Red Hat Enterprise Linux Server release 5.2 (Tikanga)
Kernel \r on an \m

root@host# uname -a
Linux host 2.6.18-92.el5 #1 SMP Tue Apr 29 13:16:12 EDT 2008 i686 i686 i386 GNU/Linux
root@host#

==============================================
So the first question is, how can I see the 4 internal disks?
Secondly, can I setup mirroring on the OS as well as the oracle filesystems which need to be created? DO I still need to do RAID mirroring (quite cryptic from what I have read/researched) or can I do LVM mirroring like in HPUX or Solaris??

Unfortunately as we all know, this is urgent (isn't it always) I would really really appreciate all help and advice.

Thanks very much
Hasan

[Steven E. Protter]

Shalom,

Probably the system was set up with hardware raid 1 configuration before OS install.

When hardware raid is used, the OS does not see the individual disks, it only sees the disks presented to it by the hardware.

Typically, in your setup the system will see two disks, 1 73 GB, 1 146 GB, which is what the system has made available to it.

SEP

[Hasan Saiyid]

Hi Steve,

Thanks for the reply. Can you please let me know how I can verify that there is infact a hardware RAID setup?, the system is in build stage so I can shutdown or boot in single user that is no problem.
Secondly, if hardware RAID is setup and the OS can't even see the disks, then I guess the OS mirror is out of the question right?
Thanks

[Marco Wessel]

The '/dev/cciss/' device nodes will tell you the hardware being used is a SmartArray, which is a hardware RAID card. (And a pretty good one, at that.)

To verify you are indeed using RAID 1 volumes and your disks are OK, you can get the hpacucli (HP Array Configuration Utility Command Line Interface) from HP.

http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareDescription.jsp?lang=en&cc=us&swItem=MTX-673eb0ec605b4a2bac35ebb18c&jumpid=reg_R1002_USEN

You might use it as follows:
root@dbsrv:~# hpacucli ctrl slot=0 ld all show
Smart Array 6i in Slot 0

array A
logicaldrive 1 (558 GB, 5, OK)

array B
logicaldrive 2 (279 GB, 1+0, OK)

root@dbsrv:~# hpacucli ctrl slot=0 pd all show
Smart Array 6i in Slot 0

array A
physicaldrive 2:0 (port 2:id 0 , Parallel SCSI, 300 GB, OK)
physicaldrive 2:1 (port 2:id 1 , Parallel SCSI, 300 GB, OK)
physicaldrive 2:2 (port 2:id 2 , Parallel SCSI, 300 GB, OK)
physicaldrive 2:3 (port 2:id 3 , Parallel SCSI, 300 GB, OK, spare)

array B
physicaldrive 2:3 (port 2:id 3 , Parallel SCSI, 300 GB, OK, spare)
physicaldrive 2:4 (port 2:id 4 , Parallel SCSI, 300 GB, OK)
physicaldrive 2:5 (port 2:id 5 , Parallel SCSI, 300 GB, OK)

[Hasan Saiyid]

Marco... thanks soooo much. I was able to verify that the disks are in fact in hardware raid 1+0. What I don;t understand is how it got done, because the onsite admin claims he just went through a regular CD install on the console and never configured any raid ?? what do you think?

Lastly... I don't want to constantly bug you guys but for my clarification, can you please tell me if a hardware raid is present, is there any reason to setup OS mirroring as well via LVM, and is that even possible since the OS cannot see 2 devices, it just sees one device ??

Thanks once again Steve and Marco.

[Marco Wessel]

Well, I tend to do this manually so I'm not completely sure but I believe installing with certain automatic ways tends to autocreate arrays in certain ways, depending on the number of identical disks inserted. So that may be how they were created.

I consider hardware raid to be much, much better than any form of software raid. So you're essentially set on the mirroring part.

LVM is not raid, it is a volume manager. With it, you could combine the two mirrored volumes to be a larger volume. Sort-of like a RAID 1+0 (LVM would do striping) except it doesn't require an even number of identically sized disks for maximum efficiency. If you intended for the two volumes to be combined into one, you'd need LVM. Otherwise just leave it where it is now.

[Steven E. Protter]

Shalom Hasan,

Boot the box at console.

You will see a smart array utility you can invoke to see hardware RAID configuration.

This will enable you to see the setup.

It also is possible if you install the HP insight CD that shipped with your box that you can enter via a browser and see system raid configuration.

SEP

[Hasan Saiyid]

Thank you guys for the wonderful responses, my issue is resolved.
Marco, thanks again for the detailed steps.
Shalom Steve ! (will checkout your blog)