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Re: switch from file system to raw device

From: Igor <igor.news_at_merkudelete.org>
Date: Thu, 16 Sep 2004 08:32:34 +0200
Message-ID: <pan.2004.09.16.06.32.33.554923@merkudelete.org>


Thanks for your comments.

> If your environment is that susceptible to the disk performance, you might
> also get some benefit from the old (myth-age) style of separating
> tablespaces to separate disk drives & controllers, etc. However, other
> than for keeping someone busy, I would not recommend resurrecting those
> techniques!

We did so when there was something to separate on, when we had disks, which where seen/addressable individually. As we passed from single disk handling (IBM SSA 7133) to Raid5 (IBM FAStT SAN), there of course is not really much one can address individually. But in fact, we separated rbs from tmp, data from indexes and so on.

In all the contributes or documentation I read, people often say, that "it is not worth the effort" to go onto raw device instead of going to file system. Maybe I am blind or professionally deformed, but I find no particular effort in handling raw devices (maybe, because I started to do so about ten years ago; my first db was on file system and there was no performance issue to be investigated).
When you back up an open database, depending on workload and size of the db and backup destination/application, individual tablespace handling and backing up datafiles of single tablespaces must be done, so whether I am backing up /dev/lvXYZ_file or /home00/oracle/oradata/XYZ/file.dbf does not make any real difference for the backup procedure. Recreating a copy of an existing db also is not really an issue if you let the backup procedure make a snapshot of the environment (like lv create scripts). But, of course, we are individuals, different experiences as for hw or backup sw or OS, so individual preferences may apply. And I guess that's just it, personal preference.

By the way, we use raw devices on small Linux systems, too.

Thank your very much for all your comments. Have a nice day.
Best regards, Igor Received on Thu Sep 16 2004 - 01:32:34 CDT

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