From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1S1Nf1-00084D-RM for garchives@archives.gentoo.org; Sat, 25 Feb 2012 19:52:04 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 89D72E0C14; Sat, 25 Feb 2012 19:51:54 +0000 (UTC) Received: from svr-us4.tirtonadi.com (svr-us4.tirtonadi.com [69.65.43.212]) by pigeon.gentoo.org (Postfix) with ESMTP id 03C1BE0C14 for ; Sat, 25 Feb 2012 19:50:50 +0000 (UTC) Received: from mail-vw0-f53.google.com ([209.85.212.53]) by svr-us4.tirtonadi.com with esmtpsa (TLSv1:RC4-SHA:128) (Exim 4.69) (envelope-from ) id 1S1Ndt-002oNQ-EW for gentoo-user@lists.gentoo.org; Sun, 26 Feb 2012 02:50:53 +0700 Received: by vbbfc21 with SMTP id fc21so2625230vbb.40 for ; Sat, 25 Feb 2012 11:50:47 -0800 (PST) Received-SPF: pass (google.com: domain of pandu@poluan.info designates 10.220.155.196 as permitted sender) client-ip=10.220.155.196; Authentication-Results: mr.google.com; spf=pass (google.com: domain of pandu@poluan.info designates 10.220.155.196 as permitted sender) smtp.mail=pandu@poluan.info Received: from mr.google.com ([10.220.155.196]) by 10.220.155.196 with SMTP id t4mr4521066vcw.52.1330199447636 (num_hops = 1); Sat, 25 Feb 2012 11:50:47 -0800 (PST) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.220.155.196 with SMTP id t4mr3577631vcw.52.1330199447556; Sat, 25 Feb 2012 11:50:47 -0800 (PST) Received: by 10.220.119.85 with HTTP; Sat, 25 Feb 2012 11:50:46 -0800 (PST) Received: by 10.220.119.85 with HTTP; Sat, 25 Feb 2012 11:50:46 -0800 (PST) In-Reply-To: <20120225200305.2e9ae382@gmail.com> References: <20120225095751.7ad3d9d6@gmail.com> <20120225200305.2e9ae382@gmail.com> Date: Sun, 26 Feb 2012 02:50:46 +0700 Message-ID: Subject: Re: [gentoo-user] Re: Safe way to test a new kernel? From: Pandu Poluan To: gentoo-user@lists.gentoo.org Cc: emailgrant@gmail.com Content-Type: multipart/alternative; boundary=f46d043c7dbe8d540d04b9cf31f0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - svr-us4.tirtonadi.com X-AntiAbuse: Original Domain - lists.gentoo.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - poluan.info X-Archives-Salt: 24f2d3f2-22ab-4702-9216-4e992685fb7d X-Archives-Hash: 5a19d713b9fe3e77587d44a88632f89b --f46d043c7dbe8d540d04b9cf31f0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Feb 26, 2012 2:05 AM, "Robert David" wrote: > > V Sat, 25 Feb 2012 10:32:20 -0800 > Grant naps=C3=A1no: > > > >> >> I need to test a kernel config change on a remote system. Is > > >> >> there a safe way to do this? The fallback thing in grub has > > >> >> never worked for me. When does that ever work? > > >> > > > >> > > > >> > You can press ESC in the Grub screen and it will take you to > > >> > text-only mode. There, you select an entry, press "e" and edit > > >> > it. Press ENTER when you're finished, and then press "b" to boot > > >> > your modified entry. > > >> > > > >> > That way, you can boot whatever kernel you want if the current > > >> > one doesn't work. > > >> > > >> I can't do that remotely though. I'm probably asking for something > > >> that doesn't exist. > > >> > > >> - Grant > > >> > > > > > > Don't do that if you don't have some tool like KVM, or other remote > > > management of the server. Or if it is available in the data center, > > > just call them and order this service for the time you need to do > > > updates. > > > > > > This is why I don't use gentoo on servers any more, just because > > > I rather stay safe than sorry. > > > > How is another distro different in this situation? > > > > - Grant > > Just because when using distros like Centos/RHEL or Debian stable, you > have very little chance that the kernel released will fail. Due to > extensive testing, user base and update policy. And major kernel update > you done only once in few years and the transition is tested before > release done (though you are supposed to test yourself to be safe). > > This is not saying that gentoo is bad, I'm very big fan of gentoo. > But you have to concern where it use and where not. > > Robert. > Anecdotal, but... I once had an Ubuntu VM that can't shutdown after a kernel update. First boot after update went well, but when I rebooted it again, it pegged its vCPUs at 100% before I ordered the Xen hypervisor to put it out of its misery. The bug was apparently in the portion of the kernel running in the primary CPU that's responsible for shutting down the other CPUs before cutting the power. And IIRC, this bug affects all multi-processor configuration. So, as you can see, binary distros can still fuck up royal time. Not to mention that if you have an exotic configuration, support for your configuration might not be built into the kernel by the distro. Somehow I believe people deploying Gentoo servers will be much more careful... Rgds, --f46d043c7dbe8d540d04b9cf31f0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Feb 26, 2012 2:05 AM, "Robert David" <robert.david.public@gmail.com> wrote: >
> V Sat, 25 Feb 2012 10:32:20 -0800
> Grant <emailgrant@gmail.com= > naps=C3=A1no:
>
> > >> >> I need to test a kernel config change on a remo= te system. =C2=A0Is
> > >> >> there a safe way to do this? =C2=A0The fallback= thing in grub has
> > >> >> never worked for me. =C2=A0When does that ever = work?
> > >> >
> > >> >
> > >> > You can press ESC in the Grub screen and it will ta= ke you to
> > >> > text-only mode. There, you select an entry, press &= quot;e" and edit
> > >> > it. Press ENTER when you're finished, and then = press "b" to boot
> > >> > your modified entry.
> > >> >
> > >> > That way, you can boot whatever kernel you want if = the current
> > >> > one doesn't work.
> > >>
> > >> I can't do that remotely though. =C2=A0I'm proba= bly asking for something
> > >> that doesn't exist.
> > >>
> > >> - Grant
> > >>
> > >
> > > Don't do that if you don't have some tool like KVM, = or other remote
> > > management of the server. Or if it is available in the data = center,
> > > just call them and order this service for the time you need = to do
> > > updates.
> > >
> > > This is why I don't use gentoo on servers any more, just= because
> > > I rather stay safe than sorry.
> >
> > How is another distro different in this situation?
> >
> > - Grant
>
> Just because when using distros like Centos/RHEL or Debian stable, you=
> have very little chance that the kernel released will fail. Due to
> extensive testing, user base and update policy. And major kernel updat= e
> you done only once in few years and the transition is tested before > release done (though you are supposed to test yourself to be safe). >
> This is not saying that gentoo is bad, I'm very big fan of gentoo.=
> But you have to concern where it use and where not.
>
> Robert.
>

Anecdotal, but...

I once had an Ubuntu VM that can't shutdown after a kernel update. F= irst boot after update went well, but when I rebooted it again, it pegged i= ts vCPUs at 100% before I ordered the Xen hypervisor to put it out of its m= isery.

The bug was apparently in the portion of the kernel running in the prima= ry CPU that's responsible for shutting down the other CPUs before cutti= ng the power. And IIRC, this bug affects all multi-processor configuration.=

So, as you can see, binary distros can still fuck up royal time. Not to = mention that if you have an exotic configuration, support for your configur= ation might not be built into the kernel by the distro.

Somehow I believe people deploying Gentoo servers will be much more care= ful...

Rgds,

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