From: Roman Shaposhnik <rvs@sun.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] 9pfuse and O_APPEND
Date: Fri, 19 Dec 2008 12:10:10 -0800 [thread overview]
Message-ID: <998EB623-CFD3-4E15-BD85-D2111D8A896B@sun.com> (raw)
In-Reply-To: <a549cb998598f17f5cc92ed39aa6b7c3@quanstro.net>
On Dec 19, 2008, at 11:56 AM, erik quanstrom wrote:
>> Two questions:
>> 1. But before I ask this one: I don't deny that per-file append-
>> only
>> is *extremely* useful. My question is a different one: what is
>> the danger of N clients accesing the file X in append-only mode
>> and M clients accesing it in random access mode? Could you,
>> please, give a concrete scenario?
>
> credit geoff for bringing this up: upas mailboxes.
> suppose you have upas/deliver trying to deliver a message and at
> the same time you have upas/fs trying to rewrite the mailbox.
> (play along for a bit. ignore L.mbox and the temporary mbox
> tricks.)
It is difficult to answer your question without knowing what rewrite
actually does and how mailboxes are structured. But in an imaginary
world where a mailbox is a list of constant sized blocks (size<iounit)
a bunch of simultaneous appends and rewrites of existing blocks
would work perfectly well.
Thanks,
Roman.
next prev parent reply other threads:[~2008-12-19 20:10 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-18 23:34 Roman Shaposhnik
2008-12-18 23:57 ` Russ Cox
2008-12-19 0:03 ` ron minnich
2008-12-19 3:06 ` Roman Shaposhnik
2008-12-19 3:26 ` ron minnich
2008-12-19 3:59 ` Roman Shaposhnik
2008-12-19 16:44 ` ron minnich
2008-12-19 19:21 ` Anthony Sorace
2008-12-19 19:31 ` erik quanstrom
2008-12-19 19:41 ` ron minnich
2008-12-19 19:59 ` Roman Shaposhnik
2008-12-19 20:06 ` erik quanstrom
2008-12-19 20:18 ` Charles Forsyth
2008-12-21 5:08 ` Roman V. Shaposhnik
2008-12-19 3:03 ` Roman Shaposhnik
2008-12-19 3:43 ` erik quanstrom
2008-12-19 3:54 ` Roman Shaposhnik
2008-12-19 4:13 ` geoff
2008-12-19 8:23 ` Russ Cox
2008-12-19 19:49 ` Roman Shaposhnik
2008-12-19 19:56 ` erik quanstrom
2008-12-19 20:10 ` Roman Shaposhnik [this message]
2008-12-19 20:22 ` erik quanstrom
2008-12-19 20:02 ` ron minnich
2008-12-19 14:21 ` erik quanstrom
2008-12-19 21:00 ` ron minnich
2008-12-19 21:32 ` Charles Forsyth
2008-12-19 21:29 ` ron minnich
2008-12-21 5:05 ` Roman V. Shaposhnik
2008-12-21 14:45 ` erik quanstrom
2008-12-22 10:02 ` roger peppe
2008-12-25 6:04 ` Roman Shaposhnik
2008-12-25 6:33 ` erik quanstrom
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