Ulf, Have you considered using systemtap? There is a recipe here that could be used to find out whats going on;
http://sourceware.org/systemtap/wiki/WSDeviceMonitor?highlight=%28% 28WarStories%29%29 I'm not sure how well that would work with ocfs2. Unlike dtrace, systemtap can be more "uneven" in coverage. Its also something that requires a bit of fiddling (installing debuginfo packages). The recipe above traps vfs_read and vfs_write so should work as a first stab at identifying the process id thats causing the I/O. I'd also advise some thought if its to be used on a production environment. Having said that, I've used it on a production oracle RAC database server and found it very valuable. I don't recall you mentioning the distribution, but RH, CentOS, and oracle's version of CentOS should all work. As always, read the instructions on the label, etc... Andy On Mon, 2008-02-18 at 23:14 -0800, Ulf Zimmermann wrote: > Forgot to mention, this remote server is just Oracle. It has one standby > database and one local database, the local one is suppose to be idle, > i.e. nothing connecting to it, besides once in a while for available > check. > > While the primary database of the standby was down, I saw less disk read > access, but every 5 minutes for about 60 seconds I would see > 50-60MB/sec. After the primary came back up, read access is as high as > 160MB/sec. > > We are only seeing it on this single node of the remote standby. The > local standby (on EXT3) is not doing the same thing. > > > -----Original Message----- > > From: Sunil Mushran [mailto:[EMAIL PROTECTED] > > Sent: Monday, February 18, 2008 19:28 > > To: Ulf Zimmermann > > Cc: [email protected] > > Subject: Re: [Ocfs2-users] Anyone have an idea how to find file i/o > > throughput? > > > > If a userspace process is behind the io surge, then strace should > help. > > But determining the process may require a bit of trial and error. > > > > Ulf Zimmermann wrote: > > > We got a remote Oracle 10g R2 standby running on OCFS2. Initial when > we > > > started the standby, read I/O was < 5MB/sec on average. Since then > it > > > has grown to over 40MB/sec (longer average, it peaks much higher). > Here > > > is a graph showing this: > > > > > > http://www.alameda.net/~ulf/dbphx01.png > > > > > > We also have a local standby running (on EXT3) which is not showing > the > > > same symptom. I am trying to find where all these reads are > happening. > > > Anyone have an idea how to figure that out on Linux? > > > > > > Ulf. > > > > > > > > > _______________________________________________ > > > Ocfs2-users mailing list > > > [email protected] > > > http://oss.oracle.com/mailman/listinfo/ocfs2-users > > > > > > _______________________________________________ > Ocfs2-users mailing list > [email protected] > http://oss.oracle.com/mailman/listinfo/ocfs2-users ________________________________________________________________________ In order to protect our email recipients, Betfair Group use SkyScan from MessageLabs to scan all Incoming and Outgoing mail for viruses. ________________________________________________________________________ _______________________________________________ Ocfs2-users mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-users
