Re: are we able to decommission multi nodes at one time?
It means that may be some replicas will be stay in under replica state? 2013/4/3 Azuryy Yu azury...@gmail.com bq. then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. sorry for typo. Correct for it: then namenode start to copy block replicates on DN-1 to another DN, supposed DN-2. On Wed, Apr 3, 2013 at 9:51 AM, Azuryy Yu azury...@gmail.com wrote: It's different. If you just want to stop DN-1 a short time, just kill the DataNode process on DN-1. then do what you want. during this time, Namenode cannot receive the heart beat from DN-1, then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. But when you start DN-1 again, Namenode receive the DN-1 registration, then namenode stop to copy the DN-1's block replicates even if NN doesn't finish coping. Am I explain clearly? On Wed, Apr 3, 2013 at 9:43 AM, Henry Junyoung Kim henry.jy...@gmail.com wrote: @Harsh What's the reasons to make big gaps for removing nodes between decommission and just down nodes? In my understanding, both are necessary to copy un-replicated blocks to another alive nodes. If main costs of them are this one, total elapsed time couldn't be big different. Could you share some articles or documents to understand about decommissioning procedures? - explaining is always thanks ;) 2013. 4. 2., 오후 5:37, Harsh J ha...@cloudera.com 작성: Yes, you can do the downtime work in steps of 2 DNs at a time, especially since you mentioned the total work would be only ~30mins at most. On Tue, Apr 2, 2013 at 1:46 PM, Henry Junyoung Kim henry.jy...@gmail.com wrote: the rest of nodes to be alive has enough size to store. for this one that you've mentioned. its easier to do so in a rolling manner without need of a decommission. to check my understanding, just shutting down 2 of them and then 2 more and then 2 more without decommissions. is this correct? 2013. 4. 2., 오후 4:54, Harsh J ha...@cloudera.com 작성: Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J -- Harsh J
Re: are we able to decommission multi nodes at one time?
not at all. so don't worry about that. On Wed, Apr 3, 2013 at 2:04 PM, Yanbo Liang yanboha...@gmail.com wrote: It means that may be some replicas will be stay in under replica state? 2013/4/3 Azuryy Yu azury...@gmail.com bq. then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. sorry for typo. Correct for it: then namenode start to copy block replicates on DN-1 to another DN, supposed DN-2. On Wed, Apr 3, 2013 at 9:51 AM, Azuryy Yu azury...@gmail.com wrote: It's different. If you just want to stop DN-1 a short time, just kill the DataNode process on DN-1. then do what you want. during this time, Namenode cannot receive the heart beat from DN-1, then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. But when you start DN-1 again, Namenode receive the DN-1 registration, then namenode stop to copy the DN-1's block replicates even if NN doesn't finish coping. Am I explain clearly? On Wed, Apr 3, 2013 at 9:43 AM, Henry Junyoung Kim henry.jy...@gmail.com wrote: @Harsh What's the reasons to make big gaps for removing nodes between decommission and just down nodes? In my understanding, both are necessary to copy un-replicated blocks to another alive nodes. If main costs of them are this one, total elapsed time couldn't be big different. Could you share some articles or documents to understand about decommissioning procedures? - explaining is always thanks ;) 2013. 4. 2., 오후 5:37, Harsh J ha...@cloudera.com 작성: Yes, you can do the downtime work in steps of 2 DNs at a time, especially since you mentioned the total work would be only ~30mins at most. On Tue, Apr 2, 2013 at 1:46 PM, Henry Junyoung Kim henry.jy...@gmail.com wrote: the rest of nodes to be alive has enough size to store. for this one that you've mentioned. its easier to do so in a rolling manner without need of a decommission. to check my understanding, just shutting down 2 of them and then 2 more and then 2 more without decommissions. is this correct? 2013. 4. 2., 오후 4:54, Harsh J ha...@cloudera.com 작성: Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J -- Harsh J
Re: are we able to decommission multi nodes at one time?
thanks for all. my strategies for removing from 15 DN to 8 DN. 1. kill two DNs at same time. : NN will detect nodes' down and he will try to retain replication factors of lost blocks. 2. check your NN web UI. there is an info to let you know counts of under-replicated blocks. 3. if it is returned to 0 again, you can do remove other 2 DNs again. let's start from first again. this scenario is what I did. my cluster is working well. ;) thanks for all. 2013. 4. 3., 오후 5:18, Azuryy Yu azury...@gmail.com 작성: not at all. so don't worry about that. On Wed, Apr 3, 2013 at 2:04 PM, Yanbo Liang yanboha...@gmail.com wrote: It means that may be some replicas will be stay in under replica state? 2013/4/3 Azuryy Yu azury...@gmail.com bq. then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. sorry for typo. Correct for it: then namenode start to copy block replicates on DN-1 to another DN, supposed DN-2. On Wed, Apr 3, 2013 at 9:51 AM, Azuryy Yu azury...@gmail.com wrote: It's different. If you just want to stop DN-1 a short time, just kill the DataNode process on DN-1. then do what you want. during this time, Namenode cannot receive the heart beat from DN-1, then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. But when you start DN-1 again, Namenode receive the DN-1 registration, then namenode stop to copy the DN-1's block replicates even if NN doesn't finish coping. Am I explain clearly? On Wed, Apr 3, 2013 at 9:43 AM, Henry Junyoung Kim henry.jy...@gmail.com wrote: @Harsh What's the reasons to make big gaps for removing nodes between decommission and just down nodes? In my understanding, both are necessary to copy un-replicated blocks to another alive nodes. If main costs of them are this one, total elapsed time couldn't be big different. Could you share some articles or documents to understand about decommissioning procedures? - explaining is always thanks ;) 2013. 4. 2., 오후 5:37, Harsh J ha...@cloudera.com 작성: Yes, you can do the downtime work in steps of 2 DNs at a time, especially since you mentioned the total work would be only ~30mins at most. On Tue, Apr 2, 2013 at 1:46 PM, Henry Junyoung Kim henry.jy...@gmail.com wrote: the rest of nodes to be alive has enough size to store. for this one that you've mentioned. its easier to do so in a rolling manner without need of a decommission. to check my understanding, just shutting down 2 of them and then 2 more and then 2 more without decommissions. is this correct? 2013. 4. 2., 오후 4:54, Harsh J ha...@cloudera.com 작성: Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J -- Harsh J
Re: are we able to decommission multi nodes at one time?
Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J
Re: are we able to decommission multi nodes at one time?
the rest of nodes to be alive has enough size to store. for this one that you've mentioned. its easier to do so in a rolling manner without need of a decommission. to check my understanding, just shutting down 2 of them and then 2 more and then 2 more without decommissions. is this correct? 2013. 4. 2., 오후 4:54, Harsh J ha...@cloudera.com 작성: Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J
Re: are we able to decommission multi nodes at one time?
Yes, you can do the downtime work in steps of 2 DNs at a time, especially since you mentioned the total work would be only ~30mins at most. On Tue, Apr 2, 2013 at 1:46 PM, Henry Junyoung Kim henry.jy...@gmail.com wrote: the rest of nodes to be alive has enough size to store. for this one that you've mentioned. its easier to do so in a rolling manner without need of a decommission. to check my understanding, just shutting down 2 of them and then 2 more and then 2 more without decommissions. is this correct? 2013. 4. 2., 오후 4:54, Harsh J ha...@cloudera.com 작성: Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J -- Harsh J
Re: are we able to decommission multi nodes at one time?
@Harsh What's the reasons to make big gaps for removing nodes between decommission and just down nodes? In my understanding, both are necessary to copy un-replicated blocks to another alive nodes. If main costs of them are this one, total elapsed time couldn't be big different. Could you share some articles or documents to understand about decommissioning procedures? - explaining is always thanks ;) 2013. 4. 2., 오후 5:37, Harsh J ha...@cloudera.com 작성: Yes, you can do the downtime work in steps of 2 DNs at a time, especially since you mentioned the total work would be only ~30mins at most. On Tue, Apr 2, 2013 at 1:46 PM, Henry Junyoung Kim henry.jy...@gmail.com wrote: the rest of nodes to be alive has enough size to store. for this one that you've mentioned. its easier to do so in a rolling manner without need of a decommission. to check my understanding, just shutting down 2 of them and then 2 more and then 2 more without decommissions. is this correct? 2013. 4. 2., 오후 4:54, Harsh J ha...@cloudera.com 작성: Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J -- Harsh J
Re: are we able to decommission multi nodes at one time?
It's different. If you just want to stop DN-1 a short time, just kill the DataNode process on DN-1. then do what you want. during this time, Namenode cannot receive the heart beat from DN-1, then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. But when you start DN-1 again, Namenode receive the DN-1 registration, then namenode stop to copy the DN-1's block replicates even if NN doesn't finish coping. Am I explain clearly? On Wed, Apr 3, 2013 at 9:43 AM, Henry Junyoung Kim henry.jy...@gmail.comwrote: @Harsh What's the reasons to make big gaps for removing nodes between decommission and just down nodes? In my understanding, both are necessary to copy un-replicated blocks to another alive nodes. If main costs of them are this one, total elapsed time couldn't be big different. Could you share some articles or documents to understand about decommissioning procedures? - explaining is always thanks ;) 2013. 4. 2., 오후 5:37, Harsh J ha...@cloudera.com 작성: Yes, you can do the downtime work in steps of 2 DNs at a time, especially since you mentioned the total work would be only ~30mins at most. On Tue, Apr 2, 2013 at 1:46 PM, Henry Junyoung Kim henry.jy...@gmail.com wrote: the rest of nodes to be alive has enough size to store. for this one that you've mentioned. its easier to do so in a rolling manner without need of a decommission. to check my understanding, just shutting down 2 of them and then 2 more and then 2 more without decommissions. is this correct? 2013. 4. 2., 오후 4:54, Harsh J ha...@cloudera.com 작성: Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J -- Harsh J
Re: are we able to decommission multi nodes at one time?
bq. then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. sorry for typo. Correct for it: then namenode start to copy block replicates on DN-1 to another DN, supposed DN-2. On Wed, Apr 3, 2013 at 9:51 AM, Azuryy Yu azury...@gmail.com wrote: It's different. If you just want to stop DN-1 a short time, just kill the DataNode process on DN-1. then do what you want. during this time, Namenode cannot receive the heart beat from DN-1, then namenode start to copy block replicates on DN-2 to another DN, supposed DN-2. But when you start DN-1 again, Namenode receive the DN-1 registration, then namenode stop to copy the DN-1's block replicates even if NN doesn't finish coping. Am I explain clearly? On Wed, Apr 3, 2013 at 9:43 AM, Henry Junyoung Kim henry.jy...@gmail.comwrote: @Harsh What's the reasons to make big gaps for removing nodes between decommission and just down nodes? In my understanding, both are necessary to copy un-replicated blocks to another alive nodes. If main costs of them are this one, total elapsed time couldn't be big different. Could you share some articles or documents to understand about decommissioning procedures? - explaining is always thanks ;) 2013. 4. 2., 오후 5:37, Harsh J ha...@cloudera.com 작성: Yes, you can do the downtime work in steps of 2 DNs at a time, especially since you mentioned the total work would be only ~30mins at most. On Tue, Apr 2, 2013 at 1:46 PM, Henry Junyoung Kim henry.jy...@gmail.com wrote: the rest of nodes to be alive has enough size to store. for this one that you've mentioned. its easier to do so in a rolling manner without need of a decommission. to check my understanding, just shutting down 2 of them and then 2 more and then 2 more without decommissions. is this correct? 2013. 4. 2., 오후 4:54, Harsh J ha...@cloudera.com 작성: Note though that its only possible to decommission 7 nodes at the same time and expect it to finish iff the remaining 8 nodes have adequate free space for the excess replicas. If you're just going to take them down for a short while (few mins each), its easier to do so in a rolling manner without need of a decommission. You can take upto two down at a time on a replication average of 3 or 3+, and put it back in later without too much data movement impact. On Tue, Apr 2, 2013 at 1:06 PM, Yanbo Liang yanboha...@gmail.com wrote: It's reasonable to decommission 7 nodes at the same time. But may be it also takes long time to finish it. Because all the replicas in these 7 nodes need to be copied to remaining 8 nodes. The size of transfer from these nodes to the remaining nodes is equal. 2013/4/2 Henry Junyoung Kim henry.jy...@gmail.com :) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it. -- Harsh J -- Harsh J
Re: are we able to decommission multi nodes at one time?
How many nodes do you have and replication factor for it.
Re: are we able to decommission multi nodes at one time?
It's alowable to decommission multi nodes at the same time. Just write the all the hostnames which will be decommissioned to the exclude file and run bin/hadoop dfsadmin -refreshNodes. However you need to ensure the decommissioned DataNodes are minority of all the DataNodes in the cluster and the block replica can be guaranteed after decommission. For example, default replication level mapred.submit.replication=10. So if you have less than 10 DataNodes after decommissioned, the decommision process will hang. 2013/4/1 varun kumar varun@gmail.com How many nodes do you have and replication factor for it.
Re: are we able to decommission multi nodes at one time?
15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it.
Re: are we able to decommission multi nodes at one time?
You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it.
Re: are we able to decommission multi nodes at one time?
I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it.
Re: are we able to decommission multi nodes at one time?
:) currently, I have 15 data nodes. for some tests, I am trying to decommission until 8 nodes. Now, the total dfs used size is 52 TB which is including all replicated blocks. from 15 to 8, total spent time is almost 4 days long. ;( someone mentioned that I don't need to decommission node by node. for this case, is there no problems if I decommissioned 7 nodes at the same time? 2013. 4. 2., 오후 12:14, Azuryy Yu azury...@gmail.com 작성: I can translate it to native English: how many nodes you want to decommission? On Tue, Apr 2, 2013 at 11:01 AM, Yanbo Liang yanboha...@gmail.com wrote: You want to decommission how many nodes? 2013/4/2 Henry JunYoung KIM henry.jy...@gmail.com 15 for datanodes and 3 for replication factor. 2013. 4. 1., 오후 3:23, varun kumar varun@gmail.com 작성: How many nodes do you have and replication factor for it.
