Configuration steps for Mirroring 4-disks of external storage DS 2300

[rana786]

Hi all,

I need to configure mirror with four disks (4x146GB) of an external storage ds2300. The storage (disks) will be used by two rp3440 cluster systems. Can any body help me how can I do this?

Best regards,
Mostafa

[RAC_1]

How you will do allocation?? Two disks to one system and two to other?? How many controllers do yo have??

First, you need to have mirror disk software. Make sure disks are seen from OS-ioscan -fnCdisk command

lvextend -m 1 /dev/vgxx/lvolx /dev/dsk/cxtxdx

To extend lvol - /dev/vgxx/lvolx onto disk /dev/dsk/cxtxdx

[MarkSyder]

First of all make sure you have MirrorDisk.

If you're inexperienced with mirroring discs, you'll find it easiest if you use SAM. Mirroring in SAM is very user friendly.

SAM -> discs and filesystems -> logical volumes -> highlight one to mirror -> actions -> modify.

Make sure mirror on separate discs is checked.

Go back to actions -> change number of mirror copies. Select the number of mirror copies you want (probably 1).

Mark Syder (like the drink but spelt different)

[Mahesh Kumar Malik]

Hi Mostafa

1. ds2300 has to be setup in dual bus mode so that it can be connected to two servers

2. You need to have MirrorDisk/UX license on both the servers

3. If you plan to use two disks per server, they can be mirrored with each other.

4. For setting up the Cluster, you need to have External Shared storage, so same storgae area has to be presented to both servers. In ds2300 you need to create logical volume in shared mode

5. Finally you must have MC/Service Gaurd License on each server for Clustering

Regards
Mahesh

[rana786]

Hi there,

Both nodes will see all 4-disks. Actually I need half of the total (4-disks) space for application use and space should be seen from both cluster node. That is why I want to create mirror. Please provide me the docs, reference or details on it. I know it is different than doing internal disks mirroring. I have mirror disk s/w, dual controllers and disks are seen from both systems.

Best regards,
Mostafa

[rana786]

Hi RAC/Mark-Syder/Mahesh,

Please let me clear on it. Why do I need to assign two disks for each node and then it can be mirror on another node? I can not understand it. I want, all 4-disks will be used for one volume group that is cluster VG. Since I need half of the total space for cluster VG so I want to do mirror on it. I have all licences s/w, MCSG CDs. Please help, how can I do that.

Best regards,
Mostafa

[RAC_1]

You are missing something. What exactly you want?? Mirroring is for fault tolerence of on disk. If one disk goes bad you will still be working.

Is you need the lvol/vg that needs to accessible (still by one at any point of time) then install MCSG, create package and put lvol under that. So any given point of time, that will be owned by one node (it will be virtual ip, owned by one node) and if it fails, that package will be taken over by another node in cluster.

In this case vg will be cluster aware vg.
vgchage -c y vgxx and will be activated bt cluster in exclusive mode.

[rana786]

Hi RAC,

This is exactly what you said I want. I need a VG in external storage (ds2300) which will be controlled by cluster (MCSG). To have a fault tolerance in the storage disks, I want to do mirrors. I need help doing mirrors on the external 4-disks. Please give me details or any reference link to do it if possible. Thats it. I will be waiting for your help.

Best regards,
Mostafa

[RAC_1]

while it may be possile to do what you are thinking, you need to check if HPSG supports this hardware or not.

[rana786]

All H/W is supported by HP-UX.

[RAC_1]

check if MCSG supports DS2300 or not.

[Devender Khatana]

Hi,

Follow this for creating mirror between all four disks in a VG.

Suppose Device Files are.

/dev/dsk/c1t0d0
/dev/dsk/c1t0d1
/dev/dsk/c1t0d2
/dev/dsk/c1t0d3

Create VG on any one disk.


#pvcreate /dev/rdsk/c1t0d0
#pvcreate /dev/rdsk/c1t0d1
#pvcreate /dev/rdsk/c1t0d2
#pvcreate /dev/rdsk/c1t0d3

#mkdir /dev/vg01
#mknod /dev/vg01/group c 64 0x0?0000
(Where ? is the unique number confirm by "ll /dev/*/group)

#vgcreate -s 32 -e 10000 /dev/vg01 /dev/dsk/c1t0d0 /dev/dsk/c1t0d1 /dev/dsk/c1t0d2 /dev/dsk/c1t0d3

Now create required LV's with strict allocation policy so that two copies of same data are not kept on same disk. Also define the disk on which you want to keep first copy of this LV.

#lvcreate -L XXXX -s y /dev/vg01/lvol1 /dev/dsk/c1t0d0


Where XXXX is the size in MB. Repeat same for more than one LV's . Define seperate disk when space from first disk has been fully utilized.

Now create LV's mirrors onto second disk.

#lvextend -m 1 /dev/vg01/lvol1 /dev/dsk/c1t0d2

Repeat for all other LV's. Also define fourth disk for extending those LV's where you defined second disk while creating.

Like this all your LV's will be mirroed that too onto two seperate disks.

Confirm the same by
#vgdisplay -v /dev/vg01 |more

A better option will be to have a hardware level mirroring through some raid controller if you have one.

HTH,
Devender

[rana786]

Hi Devender,

Thanks. As you know I am going to configure external disks for cluster package configuration. I am confused on since its been seen same disk with different device-name from different node (node1 & node2) so do I need anything else to do on node1 to follow your procedure or just can follow your procedure. Please let me clear on it.

Best regards,
Mostafa

[Thayanidhi]

Hi Mostafa,

You can have different device names from different nodes for same physical device. During the initial setup, use the coresponding device names while importing the VGs. Make sure the VG name/VG id is same across the node for MCSG VG.
If you are not happy with above you can alter the kernel i/o structure with /etc/ioconfig using ioinit command.
See man page more details.

Regds
TT

[Devender Khatana]

Hi,

Attached is the Kernel config guide which also describes the procedure for changing disk device file on one node so that they are similar on both nodes. Once done with this you can go ahead for mirroring.

See page 7-9 of the attachment and use any one procedure.

HTH,
Devender

[rana786]

Its ok.