Messages in this thread | | | Date | Fri, 13 Jul 2001 08:36:01 -0700 (PDT) | From | "Jeffrey W. Baker" <> | Subject | Re: 2x Oracle slowdown from 2.2.16 to 2.4.4 |
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On Fri, 13 Jul 2001, Andrew Morton wrote:
> Andrew Morton wrote: > > > > Lance Larsh wrote: > > > > > > And while we're talking about comparing configurations, I'll mention that > > > I'm currently trying to compare raw and ext2 (no lvm in either case). > > > > It would be interesting to see some numbers for ext3 with full > > data journalling. > > > > Some preliminary testing by Neil Brown shows that ext3 is 1.5x faster > > than ext2 when used with knfsd, mounted synchronously. (This uses > > O_SYNC internally). > > I just did some testing with local filesystems - running `dbench 4' > on ext2-on-iDE and ext3-on-IDE, where dbench was altered to open > files O_SYNC. Journal size was 400 megs, mount options `data=journal' > > ext2: Throughput 2.71849 MB/sec (NB=3.39812 MB/sec 27.1849 MBit/sec) > ext3: Throughput 12.3623 MB/sec (NB=15.4529 MB/sec 123.623 MBit/sec) > > ext3 patches are at http://www.uow.edu.au/~andrewm/linux/ext3/ > > The difference will be less dramatic with large, individual writes.
This is a totally transient effect, right? The journal acts as a faster buffer, but if programs are writing a lot of data to the disk for a very long time, the throughput will eventually be throttled by writing the journal back into the filesystem.
For programs that write in bursts, it looks like a huge win!
-jwb
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