Messages in this thread | | | Date | Tue, 18 May 1999 20:47:37 +0200 (CEST) | From | Andrea Arcangeli <> | Subject | Re: ext2 question |
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On Mon, 17 May 1999, Theodore Y. Ts'o wrote:
>I should point out there have been some projects underway in that space, >including a (I believe defunct) logging filesystem project, and the
The logging filesystem it's not died in my mind. But the more I think at it, the more I am worried about the amound of extra work the backing storage has to do when the fs reach the wrap. Sometime in the future I think I'll sure try it to see how a logfs will scale, maybe a mimimal lazy implementation just to produce some number during reads and during writes while the log is wrapping.
Right now I think a journaled fs can blame a logging fs in global performances (I am not talking about write performances while the log is not wrapping around).
I planned to have a kernel daemon that will defrag data and move the start of the log far from the end of the log while the HD is idle but the point is that it's an huge amount of extra work for the system anyway... and if the write is faster than the defragger we'll have to wait the defrag-kernel-daemon to complete I/O to continue writing.
The good point is that a loggingfs will automagically preserve also data coherency,
Andrea Arcangeli
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