delorie.com/archives/browse.cgi   search  
Mail Archives: cygwin/2015/07/10/22:50:57

X-Recipient: archive-cygwin AT delorie DOT com
DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
:list-unsubscribe:list-subscribe:list-archive:list-post
:list-help:sender:date:from:reply-to:message-id:to:subject
:in-reply-to:references:mime-version:content-type
:content-transfer-encoding; q=dns; s=default; b=IdZNUnFFQB8BTK4h
BO+waqwZlkTgRJsFSaBmGZjteuGPbYwuhrY9xUaMxSl6iYUeLf089aW0iZIj6CRM
KneLN50cikpOi4tS1MEQs9ZbTFzPcrkm1hV+bS+qXD9Z/agNZs8zo+B3I/csiu94
fcf+WhJ4JJOAoHMwp3ih4sFFvWY=
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
:list-unsubscribe:list-subscribe:list-archive:list-post
:list-help:sender:date:from:reply-to:message-id:to:subject
:in-reply-to:references:mime-version:content-type
:content-transfer-encoding; s=default; bh=n5knOawG3c26kdkxbC/1ZN
dNwio=; b=v7fRmqUVZ1oT6XspJM8Sn8F3yTEOWGGT6gWTKNCvGEu8Ofp7dudM5s
g3mvcyRXf5VLwkerioP6w7B1K6nyQduQg6IFOx57H9kAE8o15cLgHbJyL0tjcDW1
daWYhE5Q9rJL7ABv4bDPfc571LAdqr1h51zaf1r/ugyYGhU+b3ksQ=
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=4.8 required=5.0 tests=AWL,BAYES_50,FREEMAIL_FROM,KAM_THEBAT,MIME_BASE64_BLANKS,SPF_SOFTFAIL autolearn=no version=3.3.2
X-HELO: smtp.ht-systems.ru
Date: Sat, 11 Jul 2015 05:38:38 +0300
From: Andrey Repin <anrdaemon AT yandex DOT ru>
Reply-To: cygwin AT cygwin DOT com
Message-ID: <1023815842.20150711053838@yandex.ru>
To: Warren Young <wyml AT etr-usa DOT com>, cygwin AT cygwin DOT com
Subject: Re: Telnet / SSH connection timeout on LAN
In-Reply-To: <5C24455B-3D28-4C6D-A77B-70BB5D67F0AA@etr-usa.com>
References: <1436142936994-119480 DOT post AT n5 DOT nabble DOT com> <7931485F-EEA3-4C1B-8B2C-E495EF5ED1A9 AT etr-usa DOT com> <1283519593 DOT 20150709090453 AT yandex DOT ru> <5C24455B-3D28-4C6D-A77B-70BB5D67F0AA AT etr-usa DOT com>
MIME-Version: 1.0
X-IsSubscribed: yes
X-MIME-Autoconverted: from base64 to 8bit by delorie.com id t6B2opw0015480

Greetings, Warren Young!

> On Jul 9, 2015, at 12:04 AM, Andrey Repin <anrdaemon AT yandex DOT ru> wrote:
>> 
>>> rsync requires a pretty heavy network transaction to figure
>>> out if files have changed.
>> 
>> I'm rsync'ing about 15 gigabytes of my home directory with just a few megs of
>> network exchange.

> “Just?”

> That was my definition of “heavy”.

Sorry, but you can't sync data without sending data.
And these few megs is the actual data I generate daily.

> Consider all the disk I/O required.  In its default mode, rsync must do a
> full directory tree scan on the directory to be transferred, on *both* ends.
> For each file with a different mtime or size, it must then recompute all the
> hashes in that file, again on both sides.

Wrong. In default mode, rsync only care about timestamp and size.
It will not go on hashing crusade unless explicitly told to.

> Can you really handwave away megs of network I/O and potentially gigs of
> disk I/O?  Do you never use locate(1) instead of find(1)?  Same issue.

I normally know where my stuff is, so I don't need to `find` or waste space on
`locate` hash tables.

> On top of that, the OP wants to do this every time the machine becomes
> idle.  Even if it was idle a few seconds ago, did some work, and is idle
> again, the OP wants all this work to be done all over again.

> Horribly wasteful.

> I believe Dropbox and its major competitors avoid the need for this tree
> scan by hooking into the OS’s filesystem change notification API, so that
> they don’t do any network or disk I/O until one of the files it is responsible for changes.

> That’s the right way.

VSS would be the right way, but I still did not find time to research its
extents.


-- 
With best regards,
Andrey Repin
Saturday, July 11, 2015 05:35:21

Sorry for my terrible english...

- Raw text -


  webmaster     delorie software   privacy  
  Copyright 2019   by DJ Delorie     Updated Jul 2019