Messages in this thread | | | Date | Thu, 15 Nov 2001 17:24:29 +0000 | From | "Stephen C. Tweedie" <> | Subject | Re: Numbers: ext2/ext3/reiser Performance (ext3 is slow) |
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Hi,
On Sat, Nov 10, 2001 at 06:41:15PM +0100, Oktay Akbal wrote:
> The question is, when to use what mode. I would use data=journal on my > CVS-Archive, and maybe writeback on a news-server. > But what to use for an database like mysql ?
For a database, your application will be specifying the write ordering explicitly with fsync and/or O_SYNC. For the filesystem to try to sync its IO in addition to that is largely redundant. writeback is entirely appriopriate for databases.
Remember, the key condition that ordered mode guards against is finding stale blocks in the middle of recently-allocated files. With databases, that's not a huge concern. Except during table creation, most database writes are into existing allocated blocks; and the data in the database is normally accessed directly only by a specified database process, not by normal client processes, so any leaks that do occur if the database extends its file won't be visible to normal users.
Cheers, Stephen - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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