<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">13.07.2016 09:04, Pranith Kumar
Karampuri пишет:<br>
</div>
<blockquote
cite="mid:CAOgeEnYtpL93hW1MqsOYxKK5drksDzWmGMZUywWLsjE4Paw=Rw@mail.gmail.com"
type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Jul 13, 2016 at 10:29 AM,
Dmitry Melekhov <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:dm@belkam.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:dm@belkam.com">dm@belkam.com</a></a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>13.07.2016 08:56, Pranith Kumar Karampuri пишет:<br>
</div>
<div>
<div class="h5">
<blockquote type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Jul 13, 2016
at 10:23 AM, Dmitry Melekhov <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:dm@belkam.com"
target="_blank">dm@belkam.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>13.07.2016 08:46, Pranith Kumar
Karampuri пишет:<br>
</div>
<span>
<blockquote type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed,
Jul 13, 2016 at 10:10 AM,
Dmitry Melekhov <span
dir="ltr"><<a
moz-do-not-send="true"
href="mailto:dm@belkam.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:dm@belkam.com">dm@belkam.com</a></a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0 0 0
.8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#FFFFFF"
text="#000000">
<div>13.07.2016 08:36,
Pranith Kumar Karampuri
пишет:<br>
</div>
<span>
<blockquote type="cite">
<div dir="ltr"><br>
<div
class="gmail_extra"><br>
<div
class="gmail_quote">On
Wed, Jul 13,
2016 at 9:35 AM,
Dmitry Melekhov
<span dir="ltr"><<a
moz-do-not-send="true" href="mailto:dm@belkam.com" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:dm@belkam.com">dm@belkam.com</a></a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0
0 0
.8ex;border-left:1px
#ccc
solid;padding-left:1ex">13.07.2016
01:52,
Anuradha Talur
пишет:<span><br>
<blockquote
class="gmail_quote"
style="margin:0
0 0
.8ex;border-left:1px
#ccc
solid;padding-left:1ex">
<br>
----- Original
Message -----<br>
<blockquote
class="gmail_quote"
style="margin:0
0 0
.8ex;border-left:1px
#ccc
solid;padding-left:1ex">
From: "Dmitry
Melekhov" <<a
moz-do-not-send="true" href="mailto:dm@belkam.com" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:dm@belkam.com">dm@belkam.com</a></a>><br>
To: "Pranith
Kumar
Karampuri"
<<a
moz-do-not-send="true"
href="mailto:pkarampu@redhat.com" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:pkarampu@redhat.com">pkarampu@redhat.com</a></a>><br>
Cc:
"gluster-users"
<<a
moz-do-not-send="true"
href="mailto:gluster-users@gluster.org" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:gluster-users@gluster.org">gluster-users@gluster.org</a></a>><br>
Sent: Tuesday,
July 12, 2016
9:27:17 PM<br>
Subject: Re:
[Gluster-users]
3.7.13, index
healing
broken?<br>
<br>
<br>
<br>
12.07.2016
17:39, Pranith
Kumar
Karampuri
пишет:<br>
<br>
<br>
<br>
Wow, what are
the steps to
recreate the
problem?<br>
<br>
just set file
length to
zero, always
reproducible.<br>
<br>
</blockquote>
If you are
setting the
file length to
0 on one of
the bricks
(looks like<br>
that is the
case), it is
not a bug.<br>
<br>
Index heal
relies on
failures seen
from the mount
point(s)<br>
to identify
the files that
need heal. It
won't be able
to recognize
any file<br>
modification
done directly
on bricks.
Same goes for
heal info
command which<br>
is the reason
heal info also
shows 0
entries.<br>
</blockquote>
<br>
</span> Well,
this makes
self-heal
useless then-
if any file is
accidently
corrupted or
deleted (yes!
if file is
deleted
directly from
brick this is
no recognized
by idex heal
too), then it
will not be
self-healed,
because
self-heal uses
index heal.<span><br>
</span></blockquote>
<div><br>
</div>
<div>It is
better to look
into bit-rot
feature if you
want to guard
against these
kinds of
problems.<br>
</div>
</div>
</div>
</div>
</blockquote>
<br>
</span> Bit rot detects
bit problems, not missing
files or their wrong
length, i.e. this is
overhead for such simple
task.<br>
</div>
</blockquote>
<div><br>
</div>
<div>It detects wrong length.
Because checksum won't match
anymore.<br>
</div>
</div>
</div>
</div>
</blockquote>
<br>
</span> Yes, sure. I guess that it will
detect missed files too. But it needs
far more resources, then just comparing
directories in bricks?<span><br>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<div><br>
</div>
<div>What use-case you are
trying out is leading to
changing things directly on
the brick?<br>
</div>
</div>
</div>
</div>
</blockquote>
</span> I'm trying to test gluster
failure tolerance and right now I'm not
happy with it...<br>
</div>
</blockquote>
<div><br>
</div>
<div>Which cases of fault tolerance are you
not happy with? Making changes directly on
the brick or anything else as well?<br>
</div>
<br>
</div>
</div>
</div>
</blockquote>
</div>
</div>
I'll repeat:<span class=""><br>
As I already said- if I for some reason ( real case
can be only by accident ) will delete file this will
not be detected by self-heal daemon, and, thus, will
lead to lower replication level, i.e. lower failure
tolerance. <br>
</span></div>
</blockquote>
<div><br>
To prevent such accidents you need to set selinux policies
so that files under the brick are not modified by accident
by any user. At least that is the solution I remember when
this was discussed 3-4 years back.<br>
</div>
</div>
<br>
</div>
</div>
</blockquote>
So only supported platfrom is linux? Or, may be, it is better to
improve self-healing to detect missing or wrong length files, I
guess this is very low cost in terms of host resources operation.<br>
Just a suggestion, may be we need to look to alternatives in near
future....<br>
<br>
</body>
</html>