Return-Path: X-Original-To: apmail-helix-user-archive@minotaur.apache.org Delivered-To: apmail-helix-user-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id AB9BD11C40 for ; Wed, 30 Jul 2014 20:50:36 +0000 (UTC) Received: (qmail 69245 invoked by uid 500); 30 Jul 2014 20:50:36 -0000 Delivered-To: apmail-helix-user-archive@helix.apache.org Received: (qmail 69207 invoked by uid 500); 30 Jul 2014 20:50:36 -0000 Mailing-List: contact user-help@helix.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@helix.apache.org Delivered-To: mailing list user@helix.apache.org Received: (qmail 69193 invoked by uid 99); 30 Jul 2014 20:50:35 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 30 Jul 2014 20:50:35 +0000 X-ASF-Spam-Status: No, hits=3.2 required=5.0 tests=FREEMAIL_REPLY,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of kanak.b@hotmail.com designates 65.54.190.37 as permitted sender) Received: from [65.54.190.37] (HELO BAY004-OMC1S26.hotmail.com) (65.54.190.37) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 30 Jul 2014 20:50:31 +0000 Received: from BAY182-W71 ([65.54.190.60]) by BAY004-OMC1S26.hotmail.com with Microsoft SMTPSVC(7.5.7601.22712); Wed, 30 Jul 2014 13:50:11 -0700 X-TMN: [QZIdtsdy6XpCTB3wwIu2yCHqN6pAPwJn] X-Originating-Email: [kanak.b@hotmail.com] Message-ID: Content-Type: multipart/alternative; boundary="_94efbdc9-036f-4d24-8219-e01ec79cf6bf_" From: Kanak Biscuitwala To: "user@helix.apache.org" Subject: RE: Fencing Date: Wed, 30 Jul 2014 13:50:10 -0700 Importance: Normal In-Reply-To: <68430C61537EE145A87197B7AD79D21C0EB54D5B@SXGCM504.fg.rbc.com> References: <68430C61537EE145A87197B7AD79D21C0EB51D1B@SXGCM504.fg.rbc.com>,,<68430C61537EE145A87197B7AD79D21C0EB543FE@SXGCM504.fg.rbc.com>,<68430C61537EE145A87197B7AD79D21C0EB54D3D@SXGCM504.fg.rbc.com>,,<68430C61537EE145A87197B7AD79D21C0EB54D5B@SXGCM504.fg.rbc.com> MIME-Version: 1.0 X-OriginalArrivalTime: 30 Jul 2014 20:50:11.0024 (UTC) FILETIME=[DAC02D00:01CFAC37] X-Virus-Checked: Checked by ClamAV on apache.org --_94efbdc9-036f-4d24-8219-e01ec79cf6bf_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Great=2C so then yes=2C it should be able to do what you need. From: Venkata.Krishnamoorthy@rbccm.com To: user@helix.apache.org Subject: RE: Fencing Date: Wed=2C 30 Jul 2014 20:44:42 +0000 =0A= =0A= =0A= =0A= =0A= =0A= =0A= =0A= Hi kanak=2C=0A= =0A= Implementing a custom logic to restart the process was what I was implicitl= y refering to.=0A= =0A= Thanks=2C=0A= Venkat=0A= =0A= =0A= =0A= From: Kanak Biscuitwala [mailto:kanak.b@hotmail.com]=0A= =0A= Sent: 2014=2C July=2C 30 4:42 PM =0A= To: user@helix.apache.org =0A= Subject: RE: Fencing =0A= =0A= =0A= =0A= =0A= Hi Venkata=2C=0A= =0A= =0A= =0A= =0A= It can=2C but you should know that disabling an instance simply triggers a = transition to the initial state in your state model. Within that transition= callback=2C you need to release locks or anything else that you would need= to do in your system. This doesn't=0A= force a restart of your process or anything like that unless you explicitl= y implement that logic in your callback.=0A= =0A= =0A= =0A= =0A= Kanak =0A= =0A= =0A= From: Venkata.Krishnamoorthy@rbccm.com =0A= To: user@helix.apache.org =0A= Subject: RE: Fencing =0A= Date: Wed=2C 30 Jul 2014 20:37:22 +0000 =0A= =0A= I think your response in this mail thread works for this use case:=0A= =0A= http://mail-archives.apache.org/mod_mbox/helix-user/201308.mbox/browser=0A= =0A= Thanks=2C=0A= Venkat=0A= =0A= =0A= =0A= From: Krishnamoorthy=2C Venkata=20 =0A= Sent: 2014=2C July=2C 29 4:34 PM =0A= To: user@helix.apache.org =0A= Subject: RE: Fencing =0A= =0A= =0A= =0A= Hi Kishore=2C=0A= =0A= Sorry abt the late response. The usecase is as follows:=0A= =0A= If multiple replicas of a partition has access to a common resource such as= coherence cache or a databaseassuming that some kind of locking is require= d=0A= at the application level to do write update=2C if one of the replicas beco= mes offline from the point of Helix=2C then the particular replica needs to= be forcibly restarted to avoid starvation for other replicas.=0A= =0A= =0A= I was wondering if this requirement can be achieved through Fencing concept= using Helix.=0A= =0A= Thanks=2C=0A= Venkat=0A= =0A= =0A= =0A= From: kishore g [mailto:g.kishore@gmail.com]=0A= =0A= Sent: 2014=2C July=2C 24 3:24 PM =0A= To: user@helix.apache.org =0A= Subject: Re: Fencing =0A= =0A= =0A= =0A= =0A= =0A= Hi Venkat=2C =0A= =0A= =0A= We don't have explicit support for fencing. We provide some callbacks that = can be used to deal with such scenarios. Can you give us more info on the s= cenario. What state model are you using=2C what is the shared resource and = when you say unresponsive what could=0A= be the likely cause(e.g. GC). =0A= =0A= =0A= thanks=2C =0A= Kishore G =0A= =0A= =0A= =0A= On Thu=2C Jul 24=2C 2014 at 9:57 AM=2C Krishnamoorthy=2C Venkata=0A= =0A= wrote: =0A= =0A= =0A= Is there support for Fencing ( =0A= http://en.wikipedia.org/wiki/Fencing_(computing) ) in Helix? If not=2C how = do I implement this feature to make sure that a participant that is not res= ponsive is actually shutdown in order to avoid wrongful access to shared=0A= resources and race conditions? Please let me know.=0A= =0A= Thanks=2C=0A= Venkat=0A= =0A= =0A= =0A= ________________________________________ =0A= This E-Mail (including any attachments) may contain privileged or confident= ial information. It is intended only for the addressee(s) indicated above. =0A= The sender does not waive any of its rights=2C privileges or other protecti= ons respecting this information. =0A= =0A= Any distribution=2C copying or other use of this E-Mail or the information = it contains=2C by other than an intended recipient=2C is not sanctioned and= is prohibited. =0A= If you received this E-Mail in error=2C please delete it and advise the sen= der (by return E-Mail or otherwise) immediately.=0A= =0A= This E-Mail (including any attachments) has been scanned for viruses.=20 =0A= It is believed to be free of any virus or other defect that might affect an= y computer system into which it is received and opened.=0A= =0A= However=2C it is the responsibility of the recipient to ensure that it is v= irus free.=0A= =0A= The sender accepts no responsibility for any loss or damage arising in any = way from its use. =0A= E-Mail received by or sent from RBC Capital Markets is subject to review by= Supervisory personnel.=0A= =0A= Such communications are retained and may be produced to regulatory authorit= ies or others with legal rights to the information. =0A= IRS CIRCULAR 230 NOTICE: TO COMPLY WITH U.S. TREASURY REGULATIONS=2C WE AD= VISE YOU THAT ANY U.S. FEDERAL TAX ADVICE INCLUDED IN THIS COMMUNICATION IS= NOT INTENDED OR WRITTEN TO BE USED=2C AND CANNOT BE USED=2C TO AVOID ANY U= .S. FEDERAL TAX PENALTIES OR TO PROMOTE=2C=0A= MARKET=2C OR RECOMMEND TO ANOTHER PARTY ANY TRANSACTION OR MATTER. =0A= =0A= =0A= =0A= =0A= =0A= =0A= =0A= = --_94efbdc9-036f-4d24-8219-e01ec79cf6bf_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Great=2C so then yes=2C it shoul= d be able to do what you need.

From: Ve= nkata.Krishnamoorthy@rbccm.com
To: user@helix.apache.org
Subject: RE:= Fencing
Date: Wed=2C 30 Jul 2014 20:44:42 +0000

=0A= =0A= =0A= =0A= =0A= =0A= =0A= =0A=
Hi kanak=2C=0A=
 =3B
= =0A=
Implementing a custom logic to= restart the process was what I was implicitly refering to.=0A=
 =3B
= =0A=
Thanks=2C
= =0A=
Venkat
=0A=
=0A=
=0A=
=0A= From: Kanak Biscuitwala [mailto:kan= ak.b@hotmail.com]=0A=
=0A= Sent: 2014=2C July=2C 30 4:42 PM
=0A= To: user@helix.apache.org
=0A= Subject: RE: Fencing
=0A=
=0A=
=0A=
=0A=

=0A= Hi Venkata=2C=0A=

=0A=
=0A=

=0A=
=0A=
It can=2C but you should know that disabling an instance simply trigge= rs a transition to the initial state in your state model. Within that trans= ition callback=2C you need to release locks or anything else that you would= need to do in your system. This doesn't=0A= force a restart of your process or anything like that unless you explicitl= y implement that logic in your callback.
=0A=

=0A=
=0A=

=0A=
=0A=
Kanak
=0A=
=0A=
=0A= From: Venkata.Krishnamoorthy@rbccm.com
=0A= To: user@helix.apache.org
=0A= Subject: RE: Fencing
=0A= Date: Wed=2C 30 Jul 2014 20:37:22 +0000
=0A=
=0A=
I think your response in this = mail thread works for this use case:
=0A=
 =3B
= =0A= =0A=
 =3B
= =0A=
Thanks=2C
= =0A=
Venkat
=0A=
=0A=
=0A=
=0A= From: Krishnamoorthy=2C Venkata =0A= Sent: 2014=2C July=2C 29 4:34 PM
=0A= To: user@helix.apache.org
=0A= Subject: RE: Fencing
=0A=
=0A=
=0A=
=0A=
Hi Kishore=2C=0A=
 =3B
= =0A=
Sorry abt the late response. T= he usecase is as follows:
=0A=
 =3B
= =0A=
If multiple replicas of a part= ition has access to a common resource such as coherence cache or a database= assuming that some kind of locking is required=0A= at the application level to do write update=2C if one of the replicas beco= mes offline from the point of Helix=2C then the particular replica needs to= be forcibly restarted to avoid starvation for other replicas.=0A=
=0A=
 =3B
= =0A=
I was wondering if this requir= ement can be achieved through Fencing concept using Helix.=0A=
 =3B
= =0A=
Thanks=2C
= =0A=
Venkat
=0A=
=0A=
=0A=
=0A=
From: kishore g [mailto:g.kishore@gmail.com]=0A=
=0A= Sent: 2014=2C July=2C 24 3:24 PM
=0A= To: user@helix.apache.org
=0A= Subject: Re: Fencing
=0A=
=0A=
=0A=
=0A=
=0A=
=0A=
Hi Venkat=2C
=0A=
=0A=
=0A= We don't have explicit support for fencing. We provide some callbacks that = can be used to deal with such scenarios. Can you give us more info on the s= cenario. What state model are you using=2C what is the shared resource and = when you say unresponsive what could=0A= be the likely cause(e.g. GC).
=0A=
=0A=
=0A= thanks=2C
=0A= Kishore G
=0A=
=0A=

=0A=
=0A=
On Thu=2C Jul 24=2C 2014 at 9:57 AM=2C Krishn= amoorthy=2C Venkata=0A= <=3B= Venkata.Krishnamoorthy@rbccm.com>=3B=0A= wrote:
=0A=
=0A=
=0A=
Is there support for Fencing ( =0A= http://en.wikipedia.org/wiki/Fencing_(computing) ) in Helix? If not=2C how do I implement this feature to make = sure that a participant that is not responsive is actually shutdown in orde= r to avoid wrongful access to shared=0A= resources and race conditions? Please let me know.
=0A=
 =3B
=0A=
Thanks=2C
=0A=
Venkat
=0A=
 =3B
=0A=
 =3B
=0A=
 =3B
=0A= ________________________________________
=0A= This E-Mail (including any attachments) may contain privileged or confident= ial information. =3B It is intended only for the addressee(s) indicated= above.
=0A= The sender does not waive any of its rights=2C privileges or other protecti= ons respecting this information. =3B=0A=
=0A= Any distribution=2C copying or other use of this E-Mail or the information = it contains=2C by other than an intended recipient=2C is not sanctioned and= is prohibited.
=0A= If you received this E-Mail in error=2C please delete it and advise the sen= der (by return E-Mail or otherwise) immediately.=0A=
=0A= This E-Mail (including any attachments) has been scanned for viruses.
= =0A= It is believed to be free of any virus or other defect that might affect an= y computer system into which it is received and opened.=0A=
=0A= However=2C it is the responsibility of the recipient to ensure that it is v= irus free.=0A=
=0A= The sender accepts no responsibility for any loss or damage arising in any = way from its use.
=0A= E-Mail received by or sent from RBC Capital Markets is subject to review by= Supervisory personnel.=0A=
=0A= Such communications are retained and may be produced to regulatory authorit= ies or others with legal rights to the information.
=0A= IRS CIRCULAR 230 NOTICE: =3B TO COMPLY WITH U.S. TREASURY REGULATIONS= =2C WE ADVISE YOU THAT ANY U.S. FEDERAL TAX ADVICE INCLUDED IN THIS COMMUNI= CATION IS NOT INTENDED OR WRITTEN TO BE USED=2C AND CANNOT BE USED=2C TO AV= OID ANY U.S. FEDERAL TAX PENALTIES OR TO PROMOTE=2C=0A= MARKET=2C OR RECOMMEND TO ANOTHER PARTY ANY TRANSACTION OR MATTER.
=0A=
=0A=
=0A=
=0A=
=0A=
=0A=
=0A=
=0A=
= --_94efbdc9-036f-4d24-8219-e01ec79cf6bf_--