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Re: RAC with OCFS on Win2K - archive logs destination

From: Jesse <>
Date: 19 Jan 2005 07:54:52 -0800
Message-ID: <>

First, how big is your DB, and more importantly how large are redo's
(maximum and average size at log switch if you are manually switching,
otherwise, just maximum)? How often do your redo's get switched? This will tell us how much data you will be writing to archive logs (as for deleting, I do not know much about fragmentation issues on OCFS; if anyone else does, please speak up).

Our archive logs average 250 KB (switching every 15 minutes). The maximum redo size is 100 MB (again, we control switching externally via script). We do not have any issues with disk performance.

Just to get a performance comparison. We're using a Winchester Systems FlashDisk OpenSAN FX-400 with 15kRPM FC drives (73GB each) connected via QLogic FC Host Bus Adapters (2 GB).

Here are the basic specs:
Maximum I/O rate 80,000 I/Os per second
Maximum data thruput 700 MB per second
Maximum host data transfer rate 4 host ports at 200 MB/sec. per channel

...and a link to the product:

I'm not sure how our setup and requirements compare to yours, but this info should give you an idea what you'll be dealing with. If you go with the OCFS location, I would recommend putting archive logs on a different drive than the Oracle Home (actually, having an OCFS drive just for archive logs and other backup-related files would be best, but that might not be an option for you). The larger allocation unit size might be a problem though if you're generating smaller logs more often
(less efficient, potentially wasted space).

No matter what, you need a good scheme for cleaning up the drive once the logs are backed up. In our case, we use RMAN to delete archive logs older than 7 days once they have been backed up twice. Now, since RMAN actually backs up to the same OCFS drive as the logs are written to, we use scripts to copy the backups to the nodes (again, every 15 minutes). We have other scripts that delete RMAN backups from the OCFS drive (5 days for daily incrementals/fulls, 15 days for weekly fulls) and from the nodes (after so many days and backed up offsite via TSM).

...and don't worry, your English is just fine. You'll find that the folks in this group just want/need a lot of detail and specifics before answering any questions. That's kinda the nature of Oracle I guess. Jesse Received on Wed Jan 19 2005 - 09:54:52 CST

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