RE: How to disable SCSI write cache on RHEL

From: Matthew Zito <>
Date: Wed, 30 Sep 2009 00:40:29 -0400
Message-ID: <>

Not worth the effort you're investing. You're more likely to hit a bug with regular I/O on a forced directio system than you are to have corruption due to a write on a regular filesystem for a non datafile.


-----Original Message-----

From: on behalf of Vishal Gupta Sent: Tue 9/29/2009 9:56 AM
Subject: How to disable SCSI write cache on RHEL  


Does anyone know how to disable filesystem cache at Linux (RHEL4) level? I know it can be disable using filesytemio_options=directio|setall init.ora parameters. But that does not protect the other non-database files in case of server crash. We already have SAN attached disks, so there is plenty of SAN cache to speed up the things. I want to avoid the risk of filesytem corruption on linux server crash due to filesystem buffering/caching.  

Someone on internet mentioned, one of the way is by executing following command, but which is the config file which needs to be updated to make things more persistent.  

echo 1 > /proc/scsi/sg/allow_dio  

Vishal Gupta

-- Received on Tue Sep 29 2009 - 23:40:29 CDT

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