Messages in this thread | | | Subject | Re: [RFC] extents support for EXT3 | From | Alex Tomas <> | Date | Fri, 29 Aug 2003 20:10:29 +0400 |
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>>>>> Ed Sweetman (ES) writes:
ES> in the kernels that would boot (for some reason test4's videodev ES> driver is borked so i used the mm patchset) passed the serio drivers, ES> init was unable to be found, no matter what even though it mounted the ES> root fs and the root fs is not as far as i can tell when booting on ES> older kernels, corrupted. I'm writing now in mozilla from the very ES> system but with extents turned off. I'm somewhat afraid though that ES> even though i didn't mount the partitions with the extents option, ES> that the patch may still be having an adverse effect. Right now ES> things seem pretty stable but last night apt was hanging while ES> generating locales reproducably causing the entire kernel to lose the ES> ability to do anything to the fs. This was all being tested on ES> test3-mm1. I am aware that mm does have some patches to ext3 that ES> aren't in the main kernel i believe. perhaps the xattr stuff is ES> conflicting in some way? I really have no way of testing the linus ES> tree directly because the drivers i use wont compile.
first of all, once fs gets mounted with extents support any newly created files/dirs will be stored in extents-format. thus, if you remount that fs w/o extents support you won't be able to access those files/dirs.
I really propose you don't use extents on a partitions you care about for a while.
ES> All in all though, when it was enabled, i saw really no difference ES> from when it was not enabled. dbench 16 gave me ~140MB/sec either ES> way. md5summing large files resulted in equal performance as well. I ES> got nothing even close to the kind of performance increases you showed ES> in the first mail.
quite interesting result. could you help me to investigate that? it would be great to go through following steps: 1) create fresh ext3 fs 2) mount it w/o extents option 3) run dbench 16 for few times (say, 4) make sure it performs on that filesystem (cd <mntpoint>; dbench -c ... 16) 4) unmount fs 5) recreate that fs 6) mount it with extents option 'EXT3-fs: file extents enabled' should be printed in logs 7) run dbench 16 for few times 8) unmount that fs and take a look in logs, you should see stats info about extents usage
thank you!
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