Re: To use RAW devices or not to use RAW devices.

There are other ways to gain performance before considering the use of Raw device. There are many operational drawbacks associated with Raw device. For example, the only backup command you can use to backup the raw device is dd. The Unix dd command is slow for backup and recovery. We have a 30 Gbytes database and the applications are using raw devices. The maintainence is nightmare and I am thinking to convert to use regular file system on the Raid 0+1 devices.

For mission critial critial system, please consider the following alternatives

1. Raid devices with stripe and mirror. Striping is for performance and mirror is for safety
2. Consider Cluster device with Oracle Parallel Server Option. Two or more machine can access your Oracle database to increase availablility.
3. Consider a disaster site with data replication.

Good Luck
MotoX wrote in message
<905412242.6318.0.nnrp-05.c2de712e_at_news.demon.co.uk>...
>1. Read the Oracle install docs for your platform. Most UNIX versions
>recommend raw in I/O intensive environments.
>
>2. Do some realistic stress testing on a system configured correctly for
>raw; ditto for filesystem. Get some real benchmarks for *your* system.
>
>3. Don't use raw devices unless you have good knowledge of your OS and how
>to configure/maintain raw devices on it. Ditto backup and recovery. Look at
>additional software to help you backup/resotre raw devices if you aren't
>familiar with 'dd'.
>
>4. Consider moving partitally to raw, if that suits your situation better.
>
>If it's any help, I mainly use raw devices (on AIX) on most of our large (>
>50G) Oracle databases and have found them quite easy to work with - no
>additional work messing around with filesystems every time you want to
>create/expand/move Oracle datafiles.
>
>Still, AIX has an excellent LVM and I've used UNIX for about 17 years, so
it
>wasn't like I was hitting this stuff for the first time. If you aren't
>comfortable with your OS, steer clear of raw or get some help.
>
>Oh, and make sure you skip LVM block headers on restore, and size your
>datafiles slightly smaller than the raw partitions. If you don't you'll hit
>problems. All this is explained in the Oracle install docs.
>
>MotoX.
>
>
>
>
>Greg C. wrote in message <01bddc21$d8c013a0$360baa0a_at_ictltgclark>...
>>Hi out there.
>>
>>I am working as the DBA on a new OLTP application. I need some help with
>>deciding whether we should use RAW devices. This is a 7X24 mission
>>critical app, running on some flavor of UNIX, using Oracle8. We
anticipate
>>a very high volume of transactions.
>>
>>How can I determine if RAW devices are the answer to improving
performance?
>> Are there any other paths I should consider before jumping to RAW
devices?
>>
>>Thank you for your help.
>
>
Received on Sun Sep 13 1998 - 21:43:01 CDT