Is it possible to control whether or not mongodb preallocates journal files? I'm just running some tests to get some performance benchmarks of journaling, and the first time I started mongodb with --journal it didn't preallocate the journal files, subsequent times it has preallocated them.
To be more specific, I have 2 drives: Drive 1 = SAS drive Drive 2 = SATA drive mongo data is on drive 2. When I run with the journal directory on drive 2, the journal files are never preallocated. When I set up a junction to map the journal directory on to drive 1 instead, it always preallocates the journal files there. So when performance testing the difference of having the journals on the same or separate disks, I can't seem to get a common baseline to start from. On Mar 18, 8:27 am, AdaTheDev <adathe...@...> wrote: > Is it possible to control whether or not mongodb preallocates journal > files? > > I'm just running some tests to get some performance benchmarks of > journaling, and the first time I started mongodb with --journal it > didn't preallocate the journal files, subsequent times it has > preallocated them. -- -- You received this message because you are subscribed to the Google Groups "mongodb-user" group. To post to this group, send email to mongodb-user@... To unsubscribe from this group, send email to mongodb-user+unsubscribe <at> googlegroups.com. For more options, visit this group at http://groups.google.com/group/mongodb-user?hl=en.
Yes, it does a little testing to see if there is an advantage to preallocating the files or not. http://www.mongodb.org/display/DOCS/Journaling You can manually pre-allocate the files so the tests have a common starting point. http://www.mongodb.org/display/DOCS/Journaling+Administration+Notes On Fri, Mar 18, 2011 at 8:39 AM, AdaTheDev <adathedev@...> wrote: > To be more specific, I have 2 drives: > Drive 1 = SAS drive > Drive 2 = SATA drive > > mongo data is on drive 2. When I run with the journal directory on > drive 2, the journal files are never preallocated. When I set up a > junction to map the journal directory on to drive 1 instead, it always > preallocates the journal files there. So when performance testing the > difference of having the journals on the same or separate disks, I > can't seem to get a common baseline to start from. > > > On Mar 18, 8:27 am, AdaTheDev <adathe...@...> wrote: >> Is it possible to control whether or not mongodb preallocates journal >> files? >> >> I'm just running some tests to get some performance benchmarks of >> journaling, and the first time I started mongodb with --journal it >> didn't preallocate the journal files, subsequent times it has >> preallocated them. >(Continue reading)
Thanks Scott - I ended up manually pre-allocating the files for the time when it didn't automatically. The only scenario I couldn't test was NOT having preallocation done on the faster SAS drive - as it doesn't look like you can stop it automatically preallocating (and after it's done it, you cant drop the files while mongod is running) On Mar 18, 12:15 pm, Scott Hernandez <scotthernan...@...> wrote: > Yes, it does a little testing to see if there is an advantage to > preallocating the files or not.http://www.mongodb.org/display/DOCS/Journaling > > You can manually pre-allocate the files so the tests have a common > starting point.http://www.mongodb.org/display/DOCS/Journaling+Administration+Notes > > > > > > > > On Fri, Mar 18, 2011 at 8:39 AM, AdaTheDev <adathe...@...> wrote: > > To be more specific, I have 2 drives: > > Drive 1 = SAS drive > > Drive 2 = SATA drive > > > mongo data is on drive 2. When I run with the journal directory on > > drive 2, the journal files are never preallocated. When I set up a > > junction to map the journal directory on to drive 1 instead, it always > > preallocates the journal files there. So when performance testing the > > difference of having the journals on the same or separate disks, I(Continue reading)
No, you should not remove the journal files while mongodb is running. Are you running on windows? On Fri, Mar 18, 2011 at 12:43 PM, AdaTheDev <adathedev@...> wrote: > Thanks Scott - I ended up manually pre-allocating the files for the > time when it didn't automatically. > The only scenario I couldn't test was NOT having preallocation done on > the faster SAS drive - as it doesn't look like you can stop it > automatically preallocating (and after it's done it, you cant drop the > files while mongod is running) > > On Mar 18, 12:15 pm, Scott Hernandez <scotthernan...@...> wrote: >> Yes, it does a little testing to see if there is an advantage to >> preallocating the files or not.http://www.mongodb.org/display/DOCS/Journaling >> >> You can manually pre-allocate the files so the tests have a common >> starting point.http://www.mongodb.org/display/DOCS/Journaling+Administration+Notes >> >> >> >> >> >> >> >> On Fri, Mar 18, 2011 at 8:39 AM, AdaTheDev <adathe...@...> wrote: >> > To be more specific, I have 2 drives: >> > Drive 1 = SAS drive >> > Drive 2 = SATA drive >>(Continue reading)
Yes, Win 7 64Bit. I have no production requirement to prevent preallocation, it's purely for some testing on my local machine. Very much a "nice-to-have" to complete a set of performance tests I've been running On Mar 18, 12:47 pm, Scott Hernandez <scotthernan...@...> wrote: > No, you should not remove the journal files while mongodb is running. > > Are you running on windows? > > > > > > > > On Fri, Mar 18, 2011 at 12:43 PM, AdaTheDev <adathe...@...> wrote: > > Thanks Scott - I ended up manually pre-allocating the files for the > > time when it didn't automatically. > > The only scenario I couldn't test was NOT having preallocation done on > > the faster SAS drive - as it doesn't look like you can stop it > > automatically preallocating (and after it's done it, you cant drop the > > files while mongod is running) > > > On Mar 18, 12:15 pm, Scott Hernandez <scotthernan...@...> wrote: > >> Yes, it does a little testing to see if there is an advantage to > >> preallocating the files or not.http://www.mongodb.org/display/DOCS/Journaling > > >> You can manually pre-allocate the files so the tests have a common > >> starting point.http://www.mongodb.org/display/DOCS/Journaling+Administration+Notes(Continue reading)
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