Messages in this thread | | | Date | Mon, 2 May 2005 15:23:57 +0200 (CEST) | From | Grzegorz Kulewski <> | Subject | How to flush data to disk reliably? |
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Hi,
I am writing an app that has log files. These log files must be reliably and permanently flushed to disk on some points. These log files can be: a. normal files on some (local) filesytem, b. some block device (disk/partition).
I am asking how to flush the data from these logs to disk. I know of several methods: 1. open with O_SYNC, 2. sync(2), 3. fsync, 4. fdatasync, 5. msync (if they are mmaped).
Which of these are best and most reliable for (a/b) and for (IDE/SCSI)? What are differences between them? Maybe some other method? Are there any other precautions that I should be aware of? What about write caches? Are write barriers implemented (on IDE and SATA/SCSI) or should I turn caches off?
I am using Linux 2.6. (But I will be glad to hear about differences between 2.4 and 2.6 in this aspect if there are any.)
Thanks in advance,
Grzegorz Kulewski - 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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