Dubravko Markic wrote:
Hello again,
I just want to add to my previous mail and clarify a few things. I am
testing different filesystems on the linux machine (reiser, jfs, xfs,
ext2 etc....). What i have done is that i have created a large binary
file (2Gb) and i have written a program which reads through the file and
records each individual read in miliseconds. This is for the purpose of
trying to figure out which system is best suited for video-on-demand
task. Now i have done my homework on each filesystem, including xfs, and
i know that xfs is uniqe in that it has a real-time section for faster
data processing.
As i previously wrote to you in my first mail, i am wondering if this
real-time section can be put to the test in the linux environment. I
have already created and mounted xfs with a data and a real-time
section. But then what? I mean what can i do with the real-time section.
I read somewhere that files created/moved/copied in the real-time
section have to be done in some "complicated" and tedious way. But that
it is not possbile to do this in linux? Is that true? I am left with
only being able to test the data section of the xfs system? Thanks for
all your help in advance. I hope it's a bit easier to answer my
questions now that you have a bit more input from my side.
realtime should work on Linux.
In a nutshell, you must mark the file as realtime before the first write to it,
(actually, I think, anytime when it is of 0 length) and after that you must do
direct IO to/from the file (I believe that direct IO is still a requirement,
someone can correct me if I'm wrong...)
see the xfsctl man page; mark the file as realtime with XFS_IOC_FSSETXATTR and
set the xflag: XFS_XFLAG_REALTIME. See also XFS_XFLAG_RTINHERIT.
-Eric
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