Greetings, I am aware that mounting filesystems with noatime option greatly increases speed. I have tried to follow discussion on the pros and cons of using noatime. I have however not been able to mount with the option relatime in centos 5.2. But in a production db server, which is backed up by HP DP, is it advisable to mount with noatime? Anybody care to share their experience on it? Regards Rajagopal
On Wed, Feb 3, 2010 at 2:20 AM, Rajagopal Swaminathan <raju.rajsand at gmail.com> wrote:> I am aware that mounting filesystems with noatime option greatly > increases speed. > > I have tried to follow discussion on the pros and cons of using noatime. > > I have however not been able to mount with the option relatime in centos 5.2.The relatime option seems to have some issue at this moment: http://lists.centos.org/pipermail/centos/2009-July/079698.html The patch was offered by a forum user and it was proposed to be included in the centosplus kernel. However, that did not work out. All the details are here: http://bugs.centos.org/view.php?id=3956 Akemi
On 3 February 2010 10:20, Rajagopal Swaminathan <raju.rajsand at gmail.com> wrote:> Greetings, > > I am aware that mounting filesystems with noatime option greatly > increases speed. > > I have tried to follow discussion on the pros and cons of using noatime. > > I have however not been able to mount with the option relatime in centos 5.2. > > But in a production db server, which is backed up by HP DP, is it > advisable to mount with noatime? > > Anybody care to share their experience on it? > > Regards > > Rajagopal > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >All of my DB systems and more importantly integration and functional testing systems are noatime and there is a marked difference in performance - literally cutting testing time by at least half... There is a lot of disk I/O in that... RHEL doesn't have a reltime enabled kernel so centos doesn't either by default. I believe that there is a kernel in plus that is reltime enabled but due to potentially breaking ABI compatibility with RHEL I don't make use of it. James
Rajagopal Swaminathan wrote:> But in a production db server, which is backed up by HP DP, is it > advisable to mount with noatime?noatime typically helps when dealing with lots of files, most DB servers have a small number of files that are large in size, so noatime is likely not to provide any noticeable improvement I think. nate
On 2/3/2010 2:45 PM, nate wrote:> Rajagopal Swaminathan wrote: > >> But in a production db server, which is backed up by HP DP, is it >> advisable to mount with noatime? > > noatime typically helps when dealing with lots of files, most DB servers > have a small number of files that are large in size, so noatime is > likely not to provide any noticeable improvement I think.On the other hand you are unlikely to miss it on most filesystems, especially any that you back up with a file-oriented mechanism like tar or rsync. The only time it matters is for rare apps like a mail client that might try to notify you when your mailbox has been written more recently than the last read. -- Les Mikesell lesmikesell at gmail.com