Re: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
Hi Leena, Do you have a firewall between the two DCs? If yes, connection reset can be caused by Cassandra trying to use a TCP connection which is already closed by the firewall. Please make sure that you set high connection timeout at firewall. Also, make sure your servers are not overloaded. Please see https://developer.ibm.com/answers/questions/231996/why-do-we-get-the-error-connection-reset-by-peer-d.html for general causes of connection reset. Also, as I told earlier, Cassandra troubleshooting explains it well https://docs.datastax.com/en/cassandra/2.0/cassandra/troubleshooting/trblshootIdleFirewall.html . Make sure firewall and node tcp settings are in sync such that nodes close a tcp connection before firewall does that. With firewall timeout, we generally see merkle tree request/response failing between nodes in two DCs and then repair is hung for ever. Not sure how merkle tree creation which is node specific would get impacted by multi dc setup. Are repairs with -local options completing without problems? Thanks Anuj
Re: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
Thank you for the update. The repair fails with the Error 'Failed Creating merkle tree' but does not give any additional details. With -pr running on all DC nodes, we see a peer connection reset error, which then results in hanged repair process even though the TCP connection settings looks good on all nodes. From: Anuj Wadehra <anujw_2...@yahoo.co.in> Sent: Wednesday, October 12, 2016 2:41 PM To: user Subject: Re: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr Hi Leena, First thing you should be concerned about is : Why the repair -pr operation doesnt complete ? Second comes the question : Which repair option is best? One probable cause of stuck repairs is : if the firewall between DCs is closing TCP connections and Cassandra is trying to use such connections, repairs will hang. Please refer https://docs.datastax.com/en/cassandra/2.0/cassandra/troubleshooting/trblshootIdleFirewall.html . We faced that. Also make sure you comply with basic bandwidth requirement between DCs. Recommended is 1000 Mb/s (1 gigabit) or greater. Answers for specific questions: 1.As per my understanding, all replicas will not participate in dc local repairs and thus repair would be ineffective. You need to make sure that all replicas of a data in all dcs are in sync. 2. Every DC is not a ring. All DCs together form a token ring. So, I think yes you should run repair -pr on all nodes. 3. Yes. I dont have experience with incremental repairs. But you can run repair -pr on all nodes of all DCs. Regarding Best approach of repair, you should see some repair presentations of Cassandra Summit 2016. All are online now. I attended the summit and people using large clusters generally use sub range repairs to repair their clusters. But such large deployments are on older Cassandra versions and these deployments generally dont use vnodes. So people know easily which nodes hold which token range. Thanks Anuj From: Leena Ghatpande <lghatpa...@hotmail.com>; To: user@cassandra.apache.org <user@cassandra.apache.org>; Subject: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr Sent: Wed, Oct 12, 2016 2:15:51 PM Please advice. Cannot find any clear documentation on what is the best strategy for repairing nodes on a regular basis with multiple datacenters involved. We are running cassandra 3.7 in multi datacenter with 4 nodes in each data center. We are trying to run repairs every other night to keep the nodes in good state.We currently run repair with -pr option , but the repair process gets hung and does not complete gracefully. Dont see any errors in the logs either. What is the best way to perform repairs on multiple data centers on large tables. 1. Can we run Datacenter repair using -dc option for each data center? Do we need to run repair on each node in that case or will it repair all nodes within the datacenter? 2. Is running repair with -pr across all nodes required , if we perform the step 1 every night? 3. Is cross data center repair required and if so whats the best option? Thanks Leena
Re: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
Don't do pr repairs when using incremental repair, you'll just end up with loads of anti-compactions. On 12 October 2016 at 19:11, Harikrishnan Pillai <hpil...@walmartlabs.com> wrote: > In my experience dc local repair node by node with > Pr and par options is best .full repair increased sstables > A lot and take days to compact it back or another > Easy option for repair is use a spark job ,read all data with > Consistency all and increase read repair chance to > 100 % or use Netflix tickler > > Sent from my iPhone > > On Oct 12, 2016, at 11:44 AM, Anuj Wadehra <anujw_2...@yahoo.co.in> wrote: > > Hi Leena, > > First thing you should be concerned about is : Why the repair -pr > operation doesnt complete ? > Second comes the question : Which repair option is best? > > > One probable cause of stuck repairs is : if the firewall between DCs is > closing TCP connections and Cassandra is trying to use such connections, > repairs will hang. Please refer https://docs.datastax.com/en/ > cassandra/2.0/cassandra/troubleshooting/trblshootIdleFirewall.html . We > faced that. > > Also make sure you comply with basic bandwidth requirement between DCs. > Recommended is 1000 Mb/s (1 gigabit) or greater. > > Answers for specific questions: > 1.As per my understanding, all replicas will not participate in dc local > repairs and thus repair would be ineffective. You need to make sure that > all replicas of a data in all dcs are in sync. > > 2. Every DC is not a ring. All DCs together form a token ring. So, I think > yes you should run repair -pr on all nodes. > > 3. Yes. I dont have experience with incremental repairs. But you can run > repair -pr on all nodes of all DCs. > > Regarding Best approach of repair, you should see some repair > presentations of Cassandra Summit 2016. All are online now. > > I attended the summit and people using large clusters generally use sub > range repairs to repair their clusters. But such large deployments are on > older Cassandra versions and these deployments generally dont use vnodes. > So people know easily which nodes hold which token range. > > > > Thanks > Anuj > > -------------- > *From: *Leena Ghatpande <lghatpa...@hotmail.com>; > *To: *user@cassandra.apache.org <user@cassandra.apache.org>; > *Subject: *Repair in Multi Datacenter - Should you use -dc Datacenter > repair or repair with -pr > *Sent: *Wed, Oct 12, 2016 2:15:51 PM > > Please advice. Cannot find any clear documentation on what is the best > strategy for repairing nodes on a regular basis with multiple datacenters > involved. > > > We are running cassandra 3.7 in multi datacenter with 4 nodes in each data > center. We are trying to run repairs every other night to keep the nodes in > good state.We currently run repair with -pr option , but the repair process > gets hung and does not complete gracefully. Dont see any errors in the logs > either. > > > What is the best way to perform repairs on multiple data centers on large > tables. > > 1. Can we run Datacenter repair using -dc option for each data center? Do > we need to run repair on each node in that case or will it repair all nodes > within the datacenter? > > 2. Is running repair with -pr across all nodes required , if we perform > the step 1 every night? > > 3. Is cross data center repair required and if so whats the best option? > > > Thanks > > > Leena > > > > -- Kurt Greaves k...@instaclustr.com www.instaclustr.com
Re: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
In my experience dc local repair node by node with Pr and par options is best .full repair increased sstables A lot and take days to compact it back or another Easy option for repair is use a spark job ,read all data with Consistency all and increase read repair chance to 100 % or use Netflix tickler Sent from my iPhone On Oct 12, 2016, at 11:44 AM, Anuj Wadehra <anujw_2...@yahoo.co.in<mailto:anujw_2...@yahoo.co.in>> wrote: Hi Leena, First thing you should be concerned about is : Why the repair -pr operation doesnt complete ? Second comes the question : Which repair option is best? One probable cause of stuck repairs is : if the firewall between DCs is closing TCP connections and Cassandra is trying to use such connections, repairs will hang. Please refer https://docs.datastax.com/en/cassandra/2.0/cassandra/troubleshooting/trblshootIdleFirewall.html . We faced that. Also make sure you comply with basic bandwidth requirement between DCs. Recommended is 1000 Mb/s (1 gigabit) or greater. Answers for specific questions: 1.As per my understanding, all replicas will not participate in dc local repairs and thus repair would be ineffective. You need to make sure that all replicas of a data in all dcs are in sync. 2. Every DC is not a ring. All DCs together form a token ring. So, I think yes you should run repair -pr on all nodes. 3. Yes. I dont have experience with incremental repairs. But you can run repair -pr on all nodes of all DCs. Regarding Best approach of repair, you should see some repair presentations of Cassandra Summit 2016. All are online now. I attended the summit and people using large clusters generally use sub range repairs to repair their clusters. But such large deployments are on older Cassandra versions and these deployments generally dont use vnodes. So people know easily which nodes hold which token range. Thanks Anuj From: Leena Ghatpande <lghatpa...@hotmail.com<mailto:lghatpa...@hotmail.com>>; To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> <user@cassandra.apache.org<mailto:user@cassandra.apache.org>>; Subject: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr Sent: Wed, Oct 12, 2016 2:15:51 PM Please advice. Cannot find any clear documentation on what is the best strategy for repairing nodes on a regular basis with multiple datacenters involved. We are running cassandra 3.7 in multi datacenter with 4 nodes in each data center. We are trying to run repairs every other night to keep the nodes in good state.We currently run repair with -pr option , but the repair process gets hung and does not complete gracefully. Dont see any errors in the logs either. What is the best way to perform repairs on multiple data centers on large tables. 1. Can we run Datacenter repair using -dc option for each data center? Do we need to run repair on each node in that case or will it repair all nodes within the datacenter? 2. Is running repair with -pr across all nodes required , if we perform the step 1 every night? 3. Is cross data center repair required and if so whats the best option? Thanks Leena
Re: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
Hi Leena, First thing you should be concerned about is : Why the repair -pr operation doesnt complete ? Second comes the question : Which repair option is best? One probable cause of stuck repairs is : if the firewall between DCs is closing TCP connections and Cassandra is trying to use such connections, repairs will hang. Please refer https://docs.datastax.com/en/cassandra/2.0/cassandra/troubleshooting/trblshootIdleFirewall.html . We faced that. Also make sure you comply with basic bandwidth requirement between DCs. Recommended is 1000 Mb/s (1 gigabit) or greater. Answers for specific questions: 1.As per my understanding, all replicas will not participate in dc local repairs and thus repair would be ineffective. You need to make sure that all replicas of a data in all dcs are in sync. 2. Every DC is not a ring. All DCs together form a token ring. So, I think yes you should run repair -pr on all nodes. 3. Yes. I dont have experience with incremental repairs. But you can run repair -pr on all nodes of all DCs. Regarding Best approach of repair, you should see some repair presentations of Cassandra Summit 2016. All are online now. I attended the summit and people using large clusters generally use sub range repairs to repair their clusters. But such large deployments are on older Cassandra versions and these deployments generally dont use vnodes. So people know easily which nodes hold which token range. Thanks Anuj
RE: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
Agree. However, if we go from a world where repairs don’t run (or run very unreliably so C* can’t mark the SSTables as repaired anyways) to a world where repairs run more reliably (Spark / Tickler approach) – the impact on tombstone removal doesn’t become any worse (because SS Tables aren’t marked either ways). From: Jeff Jirsa [mailto:jeff.ji...@crowdstrike.com] Sent: Wednesday, October 12, 2016 9:25 AM To: user@cassandra.apache.org Subject: Re: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr Note that the tickle approach doesn’t mark sstables as repaired (it’s a simpler version of mutation based repair in a sense), so Cassandra has no way to prove that the data has been repaired. With tickets like https://issues.apache.org/jira/browse/CASSANDRA-6434, this has implications on tombstone removal. From: Anubhav Kale <anubhav.k...@microsoft.com<mailto:anubhav.k...@microsoft.com>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Date: Wednesday, October 12, 2016 at 9:17 AM To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Subject: RE: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr The default repair process doesn’t usually work at scale, unfortunately. Depending on your data size, you have the following options. Netflix Tickler: https://github.com/ckalantzis/cassTickler<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_ckalantzis_cassTickler=DQMFAg=08AGY6txKsvMOP6lYkHQpPMRA1U6kqhAwGa8-0QCg3M=yfYEBHVkX6l0zImlOIBID0gmhluYPD5Jje-3CtaT3ow=2YcSoi47BW6-V4BVz980x1Jr7cFbVwc8arJP3Qs4M-0=SIf2vucsd5X4ox-awetoQaxhIO5n3U3b4XzCTiCHT1g=> (Read at CL.ALL via CQL continuously :: Python) Spotify Reaper: https://github.com/spotify/cassandra-reaper<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_spotify_cassandra-2Dreaper=DQMFAg=08AGY6txKsvMOP6lYkHQpPMRA1U6kqhAwGa8-0QCg3M=yfYEBHVkX6l0zImlOIBID0gmhluYPD5Jje-3CtaT3ow=2YcSoi47BW6-V4BVz980x1Jr7cFbVwc8arJP3Qs4M-0=PMkQdggR0dnPHGJ8d7mY-vxxyitPWSlgSdFiLVOm8lA=> (Subrange repair, provides a REST endpoint and calls APIs through JMX :: Java) List subranges: https://github.com/pauloricardomg/cassandra-list-subranges<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_pauloricardomg_cassandra-2Dlist-2Dsubranges=DQMFAg=08AGY6txKsvMOP6lYkHQpPMRA1U6kqhAwGa8-0QCg3M=yfYEBHVkX6l0zImlOIBID0gmhluYPD5Jje-3CtaT3ow=2YcSoi47BW6-V4BVz980x1Jr7cFbVwc8arJP3Qs4M-0=f7n9PVE3EeDZMk2I2LhX9MnpPWV7yTGUfPKwImjIxZU=> (Tool to get subranges for a given node. :: Java) Subrange Repair: https://github.com/BrianGallew/cassandra_range_repair<https://urldefense.proofpoint.com/v2/url?u=https-3A__na01.safelinks.protection.outlook.com_-3Furl-3Dhttps-253A-252F-252Fgithub.com-252FBrianGallew-252Fcassandra-5Frange-5Frepair-26data-3D01-257C01-257CAnubhav.Kale-2540microsoft.com-257Cd8ed7c743f3a42ebac1808d3e94a97e4-257C72f988bf86f141af91ab2d7cd011db47-257C1-26sdata-3DrnOdSYfxRuV0RiXnI9HcLB220StFRDXSCMdoOQKcfvE-253D-26reserved-3D0=DQMFAg=08AGY6txKsvMOP6lYkHQpPMRA1U6kqhAwGa8-0QCg3M=yfYEBHVkX6l0zImlOIBID0gmhluYPD5Jje-3CtaT3ow=2YcSoi47BW6-V4BVz980x1Jr7cFbVwc8arJP3Qs4M-0=9pPoqSUhM0LtWSO_nhHuqqtY9kvhMaoPIcg4PfFLGx0=> (Tool to subrange repair :: Python) Mutation Based Repair (Not ready yet): https://issues.apache.org/jira/browse/CASSANDRA-8911<https://urldefense.proofpoint.com/v2/url?u=https-3A__issues.apache.org_jira_browse_CASSANDRA-2D8911=DQMFAg=08AGY6txKsvMOP6lYkHQpPMRA1U6kqhAwGa8-0QCg3M=yfYEBHVkX6l0zImlOIBID0gmhluYPD5Jje-3CtaT3ow=2YcSoi47BW6-V4BVz980x1Jr7cFbVwc8arJP3Qs4M-0=sodsKAWrUPXZ3YUR_rx2DKzeq6N6grWEhbr-JknNU0Y=> (C* is thinking of doing this - hot off the press) If you have Spark in your system, you could use that to do what Netflix Tickler does. We’re experimenting with it and seems to be the best fit for our datasets over all the other options. From: Leena Ghatpande [mailto:lghatpa...@hotmail.com] Sent: Wednesday, October 12, 2016 7:16 AM To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> Subject: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr Please advice. Cannot find any clear documentation on what is the best strategy for repairing nodes on a regular basis with multiple datacenters involved. We are running cassandra 3.7 in multi datacenter with 4 nodes in each data center. We are trying to run repairs every other night to keep the nodes in good state.We currently run repair with -pr option , but the repair process gets hung and does not complete gracefully. Dont see any errors in the logs either. What is the best way to perform repairs on multiple data centers on large tables. 1. Can we run Datacenter repair using -dc option for
Re: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
Note that the tickle approach doesn’t mark sstables as repaired (it’s a simpler version of mutation based repair in a sense), so Cassandra has no way to prove that the data has been repaired. With tickets like https://issues.apache.org/jira/browse/CASSANDRA-6434, this has implications on tombstone removal. From: Anubhav Kale <anubhav.k...@microsoft.com> Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org> Date: Wednesday, October 12, 2016 at 9:17 AM To: "user@cassandra.apache.org" <user@cassandra.apache.org> Subject: RE: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr The default repair process doesn’t usually work at scale, unfortunately. Depending on your data size, you have the following options. Netflix Tickler: https://github.com/ckalantzis/cassTickler (Read at CL.ALL via CQL continuously :: Python) Spotify Reaper: https://github.com/spotify/cassandra-reaper (Subrange repair, provides a REST endpoint and calls APIs through JMX :: Java) List subranges: https://github.com/pauloricardomg/cassandra-list-subranges (Tool to get subranges for a given node. :: Java) Subrange Repair: https://github.com/BrianGallew/cassandra_range_repair (Tool to subrange repair :: Python) Mutation Based Repair (Not ready yet): https://issues.apache.org/jira/browse/CASSANDRA-8911 (C* is thinking of doing this - hot off the press) If you have Spark in your system, you could use that to do what Netflix Tickler does. We’re experimenting with it and seems to be the best fit for our datasets over all the other options. From: Leena Ghatpande [mailto:lghatpa...@hotmail.com] Sent: Wednesday, October 12, 2016 7:16 AM To: user@cassandra.apache.org Subject: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr Please advice. Cannot find any clear documentation on what is the best strategy for repairing nodes on a regular basis with multiple datacenters involved. We are running cassandra 3.7 in multi datacenter with 4 nodes in each data center. We are trying to run repairs every other night to keep the nodes in good state.We currently run repair with -pr option , but the repair process gets hung and does not complete gracefully. Dont see any errors in the logs either. What is the best way to perform repairs on multiple data centers on large tables. 1. Can we run Datacenter repair using -dc option for each data center? Do we need to run repair on each node in that case or will it repair all nodes within the datacenter? 2. Is running repair with -pr across all nodes required , if we perform the step 1 every night? 3. Is cross data center repair required and if so whats the best option? Thanks Leena CONFIDENTIALITY NOTE: This e-mail and any attachments are confidential and may be legally privileged. If you are not the intended recipient, do not disclose, copy, distribute, or use this email or any attachments. If you have received this in error please let the sender know and then delete the email and all attachments. smime.p7s Description: S/MIME cryptographic signature
RE: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
The default repair process doesn't usually work at scale, unfortunately. Depending on your data size, you have the following options. Netflix Tickler: https://github.com/ckalantzis/cassTickler (Read at CL.ALL via CQL continuously :: Python) Spotify Reaper: https://github.com/spotify/cassandra-reaper (Subrange repair, provides a REST endpoint and calls APIs through JMX :: Java) List subranges: https://github.com/pauloricardomg/cassandra-list-subranges (Tool to get subranges for a given node. :: Java) Subrange Repair: https://github.com/BrianGallew/cassandra_range_repair<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FBrianGallew%2Fcassandra_range_repair=01%7C01%7CAnubhav.Kale%40microsoft.com%7Cd8ed7c743f3a42ebac1808d3e94a97e4%7C72f988bf86f141af91ab2d7cd011db47%7C1=rnOdSYfxRuV0RiXnI9HcLB220StFRDXSCMdoOQKcfvE%3D=0> (Tool to subrange repair :: Python) Mutation Based Repair (Not ready yet): https://issues.apache.org/jira/browse/CASSANDRA-8911 (C* is thinking of doing this - hot off the press) If you have Spark in your system, you could use that to do what Netflix Tickler does. We're experimenting with it and seems to be the best fit for our datasets over all the other options. From: Leena Ghatpande [mailto:lghatpa...@hotmail.com] Sent: Wednesday, October 12, 2016 7:16 AM To: user@cassandra.apache.org Subject: Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr Please advice. Cannot find any clear documentation on what is the best strategy for repairing nodes on a regular basis with multiple datacenters involved. We are running cassandra 3.7 in multi datacenter with 4 nodes in each data center. We are trying to run repairs every other night to keep the nodes in good state.We currently run repair with -pr option , but the repair process gets hung and does not complete gracefully. Dont see any errors in the logs either. What is the best way to perform repairs on multiple data centers on large tables. 1. Can we run Datacenter repair using -dc option for each data center? Do we need to run repair on each node in that case or will it repair all nodes within the datacenter? 2. Is running repair with -pr across all nodes required , if we perform the step 1 every night? 3. Is cross data center repair required and if so whats the best option? Thanks Leena
Repair in Multi Datacenter - Should you use -dc Datacenter repair or repair with -pr
Please advice. Cannot find any clear documentation on what is the best strategy for repairing nodes on a regular basis with multiple datacenters involved. We are running cassandra 3.7 in multi datacenter with 4 nodes in each data center. We are trying to run repairs every other night to keep the nodes in good state.We currently run repair with -pr option , but the repair process gets hung and does not complete gracefully. Dont see any errors in the logs either. What is the best way to perform repairs on multiple data centers on large tables. 1. Can we run Datacenter repair using -dc option for each data center? Do we need to run repair on each node in that case or will it repair all nodes within the datacenter? 2. Is running repair with -pr across all nodes required , if we perform the step 1 every night? 3. Is cross data center repair required and if so whats the best option? Thanks Leena
