Oracle on Raw device informations

Hi Everybody,

I never worked before on Oracle on raw device. Unfortunately I have to do it in urgent basis fro tomorrow. :)-

I have few queries which I will highly appreciate if you please reply me back. I will be using Oracle 9.2.0.4.0

1. Is any changes required for DATABASE CREATION SCRIPT? Or same as usual.

2. Any changes in tablespace creation ( locally managed with uniform extent and auto segment clause)

3. Any changes in any other oracle operations?

4. Any changes taking export and import the same.

5. If I take normal export from a unix file system database, can I import the same in raw device oracle database?

6. Any changes or suggestions for setting up backup strategy?

7. Any suggestions of Recovery?

8. ANy issue on adding more devices in future and create files


Thanks a lot

I think you are in trouble :-)

raw devices can be a bit of a pain and if you have seriously no experience in them find someone who does or you will get lost

Sumit,

There is no problem with RAW Devices. The difference between filesystem and raw is: you have to precreate the raw device before it is used for a tablespace.

Absolutely no problem with RAW devices.

In fact I would suggest: Use Raid 1+0 or 0+1 along with RAW devices. The thrughput will always be good.

So far, no benchmark results outbeat RAW Devices.

Tamil

what OS? if windows or linux have you considered Oracle Clustered file system? Are you implementing rac/ops?

A little bit of learning curve with raw devices, also consider the following
> You better have your storage planning/forecasting nailed. No resizing of a raw device like a cooked file system datafile. I know in windows on rac and ops if you need to add a raw device on the fly
you have to reboot all nodes of the cluster for the raw device to be seen
> You can't backup directly to tape with raw devices unless you use rman or export. If you are strictly copying datafiles as part of B&R you need to copy from raw to formatted file system and then to disk.
I would suggest RMAN.

regards

steve

Good Points.

I don't use Windows with Oracle.

Tamil

Quote:

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Originally posted by tamilselvan
Good Points.

I don't use Windows with Oracle.

Tamil

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yeah I did not mean to discredit the whole concept as performance gains with raw devices can be appreciable as you have so noted, just adding a few gotcha's to watch out for

are you going to use logical volume manager? (if you are in linux or unix)

tamilselvan,
Do you have any doc. how to create and manage the Raw Devices on Unix. I tryed to implement the Raw devices but i could able to achive it. i would be appreciate, if you can send me any document on it.


Thanks.

Raw device creation and maintenance are entirely dependent on OS, disk arrays and volume manager. For example in HP, lvcreate command is used to create raw device.

Tamil

I really appreciate all of yours suggestions and feedback.

For you information I will be using Solaris 5.8. I will simply create a database. I won't use RAC or OPS. Raw device will be created by the vendor. I just want to know the followings from oracle database operation perpective.

1. I have a Server. Where Oracle is already installed and 2 instances are already in game on Unix File system. I would like to create raw devices (will be done by vendor) on few new disks and will create a new database instance on that.

Question:
Is that possible? I mean on an existing database, on unix file system, can I create another instance on Raw device?

2. Once the divoce will be ready, I would like to create a database running oracle 9i database creation script. ( create database ...)

Question: Is there any change required for those scripts?

3. I have to create few Locally managed tablespace on that new instance.

Question: Any changes to create those tablespaces?

4. I will take few exports for unix file system database and import the same to Raw device instance.

Question: Any issue on that?

5. I might add few more disks later.

Question: Any issue to add few more raw devices in future when database in oroduction.

Thanks and Regards in advance

Guys any informations please!!

Question:
Is that possible? I mean on an existing database, on unix file
system, can I create another instance on Raw device?

Ans: Yes, it is possible.

2. Once the divoce will be ready, I would like to create a database running oracle 9i database creation script. ( create database ...)

Question: Is there any change required for those scripts?

Ans: No change is required.

3. I have to create few Locally managed tablespace on that new instance.

Question: Any changes to create those tablespaces?
Ans: No change is needed.

4. I will take few exports for unix file system database and import the same to Raw device instance.

Question: Any issue on that?
Ans : No issue.

5. I might add few more disks later.

Question: Any issue to add few more raw devices in future when database in oroduction.

Ans: You are not going to add the disks, the vendor who supplied the disks is going to add new disks. Don't worry.

DO NOT WORRY ABOUT RAW DEVICES. The only diff is: raw device is precreated. You get the name before even you create tablespace. Just attach those names to tablespace.

Tamil

Tamil

I recently became a raw device newbie, and thought I'd add the following:

Quote:

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You better have your storage planning/forecasting nailed. No resizing of a raw device like a cooked file system datafile.

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I'm sure this is correct if you're not using a logical volume manager and this is what stmongo was talking about. But, if you are using an LVM you can probably resize a raw logical volume on the fly and then resize the datafile. I do this on HP-UX all the time. You might want to find out if this is possible in your set-up as it'll make life much easier. Appreciate you weren't asking about this, but thought it'd be useful to know if you weren't already aware of this.

Austin