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Re: Ext3 vs. Reiser?

Stephen C. Tweedie writes:


On Fri, Jan 18, 2002 at 01:23:11PM +0000, Zoiah wrote:

I see in your benchmark that EXT3 is actually performing better than EXT2. How is that possible? Because as far as I know EXT3 is just EXT2 + journalling which means more work for the HD.

It depends very much on the workload. ext3 can often avoid seeks that ext2 has to do, because it can flush data out sequentially to the journal rather than having to seek to all the bitmap and inode blocks when writing out a change to disk. This is especially noticeable with some synchronised-IO benchmarks, where ext2 has to seek all over the disk for every IO request, whereas ext3 can just append a bit more to the journal.

So, simply put, you can see the journal as a small on-disk cache in those circumstances because the head doesn't have to search all over the disk?


Erik Smit

P.S.: Pardon me if I sound newbieish, I'm new to all this. :)

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