minor number of 2nd hosts in Oracle RAC cluster?

[John Jimenez]

I have a question in regards to clustering using Oracle RAC (I have before never used Oracle or clustering before).

Lets say I created the minor number 0x020000 for vg02 on host1. When I create the minor number in hosts2. Do I need to use a differnet minor number? or can I use 0x020000 again?

I have some Oracle documentation. When creating the volume group on host1, it mentions not to use the same minor number on the same cluster. But when it talks about the mknod on host2 it does not mention this point again.

I would think that the directions would mention this point when creating vg02 on host2, and that maybe it is a misprint and should have said not to create the same minor number on the host, instead of on the cluster.
Does it matter one way or the other?

[Chan 007]

John,

Minor number is uniuqe for each host.

I mean if you already have 0x020000 used by host2 for other vg, then you can't use 0x020000 for this vg.

Minor no is not a problem in a cluster of RAC, you can create any things as long as y r not crossing maxvgs parameter in kernel

Check
kmtune |grep maxvgs

Chan

[A. Clay Stephenson]

As long as the minor device number is unique on a per host basis, you are fine.

By convention, vg02/group gets 0x020000, vg03/groups gets 0x030000 but that is not necessary. vg05/group could use 0x020000 as long as that minor device number is not used antwhere else on that same system. It's just a little less confusing if you follow the convention. To be accurate I should actually say that the major/minor device tuple must be unique so that there can only be at most one major device 64, minor device 0x020000 node on a given host. The minor device 0x020000 might be found many times on the host but not when also paired with major device 64.

You are really taking a big step to get Oracle RAC up w/o Oracle experience. I would strongly urge you to tackle a simpler, single-host install first.

Oracle RAC normally requires the use of raw devices but if you are running 11.23, you have a new option, the Cluster File System which allows Oracle RAC under MC/SG to run on fully cooked filesystems. The filesystem looks like a conventional vxgs filesystem to each host in the cluster.

[John Jimenez]

Thanks Chan and Clay.

Yes it is free on hosts 2. That is great the I can 0x020000 on vg02 of both hosts. I would like to stick with the norm.

We just did a fresh reinstall to both of the RP7420's to 11.23 last week (Another first for me is 11 version2). The Application software Vendor that is coming in next week to install the RAC, said we did not Require MC serivce guard, so we did not purchase the MC service guard.

[John Jimenez]

Oh yeah I am not installing the RAC. But I was asked to set up the volume groups locally, and some shared between both of hosts, and also a couple of them "RAW" (another new term for me) shared between the hosts.

[A. Clay Stephenson]

I'll bet he hasn't used CFS but that would be my approach to OracleRAC. There's a lot to be said for being able to actually "see" your Oracle data. With RAW LVOL's, the only backup you are going to be able to use is RMAN (I refuse to even consider dd). One of the easist things to do with raw devices is to put down a brand-new filesystem on that "unused" disk space. Make sure you document, document, document or use CFS.

[John Jimenez]

Hi Clay,

Thanks for the info, rigt now I have no idea what either CFS or RMAN is. But I am going to find out. We have a new Oracle admin here too, and will discuss this with both of them when the Vendor comes in.

[Darrel Louis]

John,

RMAN explanation:
RMAN (Recover Manager) is a utility provided by Oracle to perform database backup and recoveries. RMAN can do off-line and on-line database backups. It integrated with 3rd-party vendors (like Veritas, Omiback, etc) to handle tape library management.

Darrel

[John Jimenez]

Thanks Darrel, We are using Data Protector 5.5, but we just have to buy the on-line extenstion licenses for Oracle.