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From: Jeff Garzik <jeff@garzik.org>
Cc: linux-raid@vger.kernel.org
Subject: Re: Converting system to raid
Date: Sun, 12 Apr 2009 13:18:44 -0400	[thread overview]
Message-ID: <49E22274.9000404@garzik.org> (raw)
In-Reply-To: <49E21A1A.4020004@hp.com>

jim owens wrote:
> To continue the pointless (but maybe entertaining) argument :)
> 
> Jeff Garzik wrote:
>> jim owens wrote:
>>> The filesystem mod-time might have nanoseconds in it, but
>>> that does not mean 2 writes 100 nanoseconds apart will have
>>> different mod-times.
>>
>> Modern Linux filesystems absolutely do do metadata updates at that 
>> level of granularity.
> 
> In filesystems it only counts if it makes it to disk.
> 
> 10,000,000 write-to-disk metadata updates per second?  I think not.

Does every write (mtime update) trigger a write to disk?  I think not :) 
  You can write (== update inode mtime) 10,000,000 times, without ever 
touching disk.  Yet you fstat() still returns a nanosecond-granularity 
mtime.

	Jeff



  reply	other threads:[~2009-04-12 17:18 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-09 23:44 Converting system to raid Timothy D. Lenz
2009-04-10  9:10 ` KwangErn Liew
2009-04-10  9:55   ` CoolCold
2009-04-10 19:43     ` Timothy D. Lenz
2009-04-10 19:53   ` Robin Hill
2009-04-10 20:45     ` Timothy D. Lenz
2009-04-10 20:59       ` Robin Hill
2009-04-10 21:26         ` Timothy D. Lenz
2009-04-10 21:51           ` Robin Hill
2009-04-11  5:29             ` Timothy D. Lenz
2009-04-11 14:29               ` CoolCold
2009-04-11 18:47                 ` Timothy D. Lenz
2009-04-12  0:53                   ` Timothy D. Lenz
2009-04-12 11:11                     ` Robin Hill
2009-04-12 19:55                       ` Timothy D. Lenz
2009-04-14  9:30                         ` Robin Hill
2009-04-17  0:47                           ` Timothy D. Lenz
2009-04-17  7:49                             ` Robin Hill
2009-04-11 14:36               ` Robin Hill
2009-04-11 15:04                 ` jim owens
2009-04-11 15:44                   ` Jeff Garzik
2009-04-11 17:40                     ` jim owens
2009-04-12 11:11                       ` Jeff Garzik
2009-04-12 16:43                         ` jim owens
2009-04-12 17:18                           ` Jeff Garzik [this message]
2009-04-10 13:22 ` Robin Hill
2009-04-10 19:22   ` Timothy D. Lenz
2009-04-10 19:50     ` Robin Hill
2009-04-11  4:40       ` Jon Lewis
2009-04-11  7:48         ` Jan Ceuleers
2009-04-11  8:50         ` Goswin von Brederlow

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