tag:blogger.com,1999:blog-1550840387946350137.post3829025552326998851..comments2022-04-03T00:39:35.304-07:00Comments on Performance Engineering and Capacity Planning: NFS and Oracle - Mount options - noac, actimeo, forcedirectio, et al.Unknownnoreply@blogger.comBlogger4125tag:blogger.com,1999:blog-1550840387946350137.post-39375141480499887922012-10-16T12:34:09.185-07:002012-10-16T12:34:09.185-07:00This is exactly what we have faced.We were getting...This is exactly what we have faced.We were getting huge performance impact with noac option and the 1GB files takes about 4-5 minutes over a 1Gb Network NFS mount. The resolution was to use mount options actimeo=0,tcp,vers=3,hard,nointr .Do not use noac, as the network traffic will he high and slow write performance. actimeo=0 do not cache anything on server which is equal to noac, but the performance was much better.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1550840387946350137.post-80915486018101380062010-08-30T10:45:38.736-07:002010-08-30T10:45:38.736-07:00You realize that if a second node extends a datafi...You realize that if a second node extends a datafile or something like that on your shared storage even though ORACLE knows the file is big enough, the file system will refuse sometimes to write to these new blocks if noac is not set? Results in an ugly error in a highly transactional environment.bryannoreply@blogger.comtag:blogger.com,1999:blog-1550840387946350137.post-56231255576486229702010-01-21T18:57:58.637-08:002010-01-21T18:57:58.637-08:00Hi Chris,
Thanks for dropping by.
Yes, I would e...Hi Chris,<br /><br />Thanks for dropping by.<br /><br />Yes, I would expect this to be the case. Without forcedirectio, the filesystem page cache mechanism would buffer the I/O thus giving the impression that it is fast.<br /><br />Regards<br />KrishnaSSKhttps://www.blogger.com/profile/01063233277470336458noreply@blogger.comtag:blogger.com,1999:blog-1550840387946350137.post-77442119549870016612010-01-21T13:43:21.390-08:002010-01-21T13:43:21.390-08:00Hi Krishna, this is vey ineresting. Did you ever c...Hi Krishna, this is vey ineresting. Did you ever compare a simple mkfile 1gig to an nfs share mounted with and without forcedirectio? In my tests with fdio or noac writing 1gig took about 1min to create, without it takes only 15secs.<br />Do you have the same effect?<br /><br />thanks chrisAnonymousnoreply@blogger.com